Centessa Pharmaceuticals (CNTA) 424B5 Prospectus supplement for primary offering

Filed Pursuant to Rule 424(b)(5)
Registration No. 333-282032

The information in this preliminary prospectus supplement and the accompanying prospectus is not complete and may be changed. A registration statement relating to the securities has been declared effective by the Securities and Exchange Commission. This preliminary prospectus supplement and accompanying prospectus are not offers to sell these securities, and we are not soliciting offers to buy these securities in any state where such offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED SEPTEMBER 11, 2024

PRELIMINARY PROSPECTUS SUPPLEMENT

(to Prospectus dated September 11, 2024)

$150,000,000

Centessa Pharmaceuticals plc

American Depositary Shares Representing Ordinary Shares

We are offering $150,000,000 of American Depositary Shares (“ADSs”) each ADS representing one ordinary share, nominal value £0.002 per share.

ADSs representing our ordinary shares are listed on The Nasdaq Global Select Market under the symbol “CNTA”. On September 10, 2024, the last reported sale price of our ADSs was $14.58 per ADS.

For a description of the rights attached to the ordinary shares, please see “Description of Share Capital and Articles of Association” beginning on page 10 of the accompanying prospectus.

We are an emerging growth company as that term is used in the Jumpstart Our Business Startups Act of 2012 and a smaller reporting company as defined in Rule 12b-2 promulgated under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and, as such, are subject to certain reduced public company reporting requirements. See “Prospectus Supplement Summary — Implications of Being an Emerging Growth Company and a Smaller Reporting Company.”

Investing in our securities involves certain risks. These risks are described under the caption “Risk Factors” beginning on page S-8 of this prospectus supplement and in the documents incorporated by reference into this prospectus supplement and the accompanying prospectus.

	Per ADS		Total
Public offering price	$		$
Underwriting discounts and commissions(1)	$		$
Proceeds to us, before expenses	$		$

⁽¹⁾  See “Underwriters” for a description of compensation payable to the underwriters.

The underwriters may also purchase up to $22,500,000 of additional ADSs from us at the public offering price, less underwriting discounts and commissions, within 30 days from the date of the final prospectus supplement.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus supplement and the accompanying prospectus. Any representation to the contrary is a criminal offense.

Delivery of the ADSs in this offering is expected to be made on or about     , 2024.

Goldman Sachs & Co. LLC Leerink Partners Evercore ISI Guggenheim Securities BMO Capital Markets

The date of this prospectus supplement is     , 2024.

Table of Contents

PROSPECTUS SUPPLEMENT

	Page
ABOUT THIS PROSPECTUS		S-1
PROSPECTUS SUPPLEMENT SUMMARY		S-2
THE OFFERING		S-6
RISK FACTORS		S-8
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS		S-11
USE OF PROCEEDS		S-14
DILUTION		S-15
UNDERWRITING		S-17
CERTAIN MATERIAL INCOME TAX CONSIDERATIONS		S-25
LEGAL MATTERS		S-35
EXPERTS		S-35
WHERE YOU CAN FIND MORE INFORMATION		S-36
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE		S-37

PROSPECTUS

	Page
ABOUT THIS PROSPECTUS		1
PROSPECTUS SUMMARY		3
RISK FACTORS		5
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS		6
SECURITIES WE MAY OFFER		9
DESCRIPTION OF SHARE CAPITAL AND ARTICLES OF ASSOCIATION		10
DESCRIPTION OF AMERICAN DEPOSITARY SHARES		31
DESCRIPTION OF DEBT SECURITIES		43
DESCRIPTION OF WARRANTS		56
DESCRIPTION OF UNITS		57
TAXATION		58
USE OF PROCEEDS		59
PLAN OF DISTRIBUTION		60
LEGAL MATTERS		63
EXPERTS		64
SERVICE OF PROCESS AND ENFORCEMENT OF LIABILITIES		65
WHERE YOU CAN FIND MORE INFORMATION		67
INCORPORATION BY REFERENCE		68

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ABOUT THIS PROSPECTUS SUPPLEMENT

This prospectus supplement and the accompanying prospectus are part of an automatic shelf registration statement on Form S-3 (File No. 333-282032) that we originally filed with the Securities and Exchange Commission (“SEC”) on September 11, 2024. This prospectus supplement describes the specific terms of this offering and also adds to and updates the information contained in the accompanying prospectus and the documents incorporated by reference into this prospectus supplement and the accompanying prospectus. The accompanying prospectus gives more general information, some of which may not apply to this offering. If there is a difference between the information contained in this prospectus supplement and the information contained in the accompanying prospectus or any document incorporated by reference, you should rely on the information in this prospectus supplement. Generally, when we refer to the prospectus, we are referring to this prospectus supplement and the accompanying prospectus combined.

We have not, and the underwriters have not, authorized anyone to provide you with information different than or inconsistent with the information contained in or incorporated by reference in this prospectus supplement, the accompanying prospectus and in any free writing prospectus that we have authorized for use in connection with this offering. We and the underwriters take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We and the underwriters are not making an offer to sell our securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus supplement, the accompanying prospectus, the documents incorporated by reference in this prospectus supplement and the accompanying prospectus, and in any free writing prospectus that we have authorized for use in connection with this offering, is accurate only as of the date of those respective documents, regardless of the time of delivery of those respective documents or the sale of our securities. Our business, financial condition, results of operations and prospects may have changed since those dates. You should read this prospectus supplement, the accompanying prospectus, the documents incorporated by reference in this prospectus supplement and the accompanying prospectus, and any free writing prospectus that we have authorized for use in connection with this offering, in their entirety before making an investment decision. You should also read and consider the information in the documents to which we have referred you in the sections of this prospectus supplement entitled “Where You Can Find More Information” and “Incorporation of Certain Information by Reference.”

Neither we, nor any of the underwriters, has done anything that would permit this offering or possession or distribution of this prospectus supplement or the accompanying prospectus in any jurisdiction where action for that purpose is required, other than in the United States. The distribution of this prospectus supplement and the accompanying prospectus and the offering of our securities in certain jurisdictions may be restricted by law. Persons outside the United States who come into possession of this prospectus supplement and the accompanying prospectus must inform themselves about, and observe any restrictions relating to, the offering of our securities and the distribution of this prospectus supplement and the accompanying prospectus outside the United States. This prospectus supplement and the accompanying prospectus do not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement and the accompanying prospectus by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

We own various trademark registrations and applications, and unregistered trademarks, including our name and our corporate logo. All other trade names, trademarks and service marks of other companies appearing in this prospectus supplement are the property of their respective holders. Solely for convenience, the trademarks and trade names in this prospectus supplement may be referred to without the ^® and ^™ symbols, but such references should not be construed as any indicator that their respective owners will not assert, to the fullest extent under applicable law, their rights thereto. We do not intend to use or display other companies’ trademarks and trade names to imply a relationship with, or endorsement or sponsorship of us by, any other companies.

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PROSPECTUS SUPPLEMENT SUMMARY

This summary highlights information contained in other parts of this prospectus supplement or incorporated by reference in this prospectus supplement from our Annual Report on Form 10-K for the year ended December 31, 2023, our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2024 and June 30, 2024 and our other filings with the SEC listed below under the heading “Incorporation of Information by Reference.” It may not contain all of the information that is important to you. You should read this entire prospectus supplement and the accompanying prospectus, including the documents incorporated by reference herein and therein carefully, including “Risk Factors” and the financial data and related notes and other information incorporated by reference herein and therein, before making an investment decision. See the section entitled “Special Note Regarding Forward-Looking Statements.”

Unless otherwise indicated or the context requires otherwise, in this prospectus supplement, references to “Centessa,” “the Company,” “our company,” “we,” “us” and “our” mean Centessa Pharmaceuticals plc, a public limited company incorporated under the laws of England and Wales.

Overview

We are a clinical-stage pharmaceutical company with a mission to discover, develop and ultimately deliver medicines that are transformational for patients. We are developing a pipeline of high conviction programs in therapeutic areas of unmet need. Subject to regulatory approval, we believe that our pipeline programs have the potential to significantly impact clinical outcomes of patients in these disease areas and compete in multi-billion-dollar markets. Our most advanced pipeline programs include: our hemophilia program with our drug candidate SerpinPC for the treatment of hemophilia B; our orexin receptor 2 (“OX2R”) agonist program with our drug candidates, including ORX750 being developed for the treatment of narcolepsy type 1 (“NT1”) and type 2 (“NT2”), and idiopathic hypersomnia (“IH”), and ORX142, being developed for the treatment of excessive daytime sleepiness (“EDS”) in select neurological, neurodegenerative and psychiatric disorders; and, our LockBody technology platform with our drug candidate LB101 for the treatment of solid tumors. We estimate that the potential market opportunity for ORX750 across NT1, NT2 and IH will be over $5 billion by 2030 and for ORX142 across select neurological, neurodegenerative and psychiatric disorders will be over $10 billion by 2040.

Recent Developments

Interim Phase 1 Study Data for ORX750

On September 10, 2024, we announced positive interim data from an ongoing Phase 1 trial of ORX750, a highly potent and selective OX2R agonist, in acutely sleep-deprived healthy volunteers. ORX750 showed clinically meaningful and statistically significant improvements in mean sleep latency at the first two doses evaluated (1.0 mg and 2.5 mg) in the Maintenance of Wakefulness Test (“MWT”) compared to placebo. More specifically, the 2.5 mg dose was shown to restore normative wakefulness² with a mean sleep latency of 32 minutes as measured by the MWT. ORX750 was also shown to have a favorable safety and tolerability profile with no observations of frequently reported on-target adverse events (“AEs”) associated with other OX2R agonists, and no cases of hepatotoxicity or visual disturbances across all three dose levels tested (1.0 mg, 2.0 mg, and 2.5 mg), as of the data cutoff date.¹ Based on the interim data, we plan to rapidly advance ORX750 into Phase 2 studies in patients with NT1, NT2, and IH beginning in the fourth quarter of 2024 pending necessary interactions with regulatory authorities.

The Phase 1 clinical study is an ongoing first-in-human, randomized, placebo-controlled study designed to evaluate the safety, tolerability and pharmacokinetics (PK) of single-ascending doses (“SAD”) and multiple-ascending doses (“MAD”) of ORX750 in healthy adult subjects. In parallel to the SAD, a placebo-controlled

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cross-over pharmacodynamic (“PD”) assessment is being performed utilizing the MWT and Karolinska Sleepiness Scale (“KSS”) in acutely sleep-deprived healthy adult subjects with the goal of rapidly generating early efficacy data to inform dosing for planned studies in patients. As of September 10, 2024, the study has completed three SAD cohorts of healthy volunteers (27 active, 9 placebo) with doses of 1.0 mg, 2.0 mg, and 2.5 mg, and has advanced through two cohorts within the cross-over assessment of acutely sleep-deprived healthy volunteers with doses of 1.0 mg (n=8) and 2.5 mg (n=8), administered as a single oral dose. Dosing in the MAD portion of the study is also ongoing.

Summary of Data:

The interim Phase 1 clinical data for ORX750 demonstrated:

• Significantly increased wakefulness in acutely sleep-deprived healthy volunteers compared to placebo at both doses tested. Treatment with ORX750 resulted in statistically significant (p<0.05) and clinically meaningful increased sleep latency on the MWT (time to sleep onset over the four sessions performed at ~2, 4, 6, and 8 hours after dosing at 11 p.m., maximum 40 minutes per session) compared to placebo across all doses. Mean sleep latencies, as measured by the MWT, for 1.0 mg dose of ORX750 and placebo were 18 minutes and 10 minutes, respectively (p-value = 0.04) (least squares mean). Mean sleep latencies, as measured by the MWT, for 2.5 mg dose of ORX750 and placebo were 32 minutes and 17 minutes, respectively (p-value = 0.01) (least squares mean). The 2.5 mg dose was shown to restore normative wakefulness with a mean sleep latency of 32 minutes as measured by the MWT.

• Favorable safety and tolerability observed as of the data cutoff date.¹

• All observed treatment related AEs were mild and transient with none leading to treatment discontinuation.

• No observations of frequently reported on-target AEs associated with other OX2R agonists, including urinary frequency, urinary urgency, insomnia, blood pressure increases, and salivary hypersecretion.

• No cases of hepatotoxicity, visual disturbances or hallucinations were observed. Additionally, there were no clinically meaningful treatment-emergent changes in hepatic and renal parameters, vital signs, or electrocardiogram (“ECG”) parameters.

• Acutely sleep-deprived healthy volunteers who received a 2.5 mg dose of ORX750 showed a significant 1.6 point improvement versus placebo in mean KSS score compared to baseline (p-value = 0.03).

• Encouraging linear PK profile supports the use of ORX750 as a once-daily oral dosing regimen with rapid absorption (plasma concentrations of ORX750 peaked at 2h after the first dose). The systemic exposure of ORX750 increased in an approximately dose-proportional manner.

1. Data cutoff date of August 26, 2024.

2. Doghramji K, et al., A normative study of the maintenance of wakefulness test (MWT). Electroencephalogr Clin Neurophysiol 1997; 103:554-62.

Narcolepsy is a chronic debilitating neurologic disorder that affects the brain’s ability to regulate the normal sleep-wake cycle. Narcolepsy is classified as two subtypes, NT1 and NT2. NT1 is caused by the profound loss of orexin-producing neurons, resulting in a dramatic reduction of orexin levels in the brain. NT1 symptoms include excessive daytime sleepiness (“EDS”), sleep paralysis, hallucinations upon waking up or falling asleep, disturbed nighttime sleep, and cataplexy. Narcolepsy without cataplexy is referred to as NT2. NT2 is associated with partial loss of orexin in approximately 30% of individuals with narcolepsy. Some individuals with NT2 progress over time to a diagnosis of NT1, with the onset of cataplexy and greater loss of orexin.

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IH is a rare neurological sleep disorder that causes EDS, characterized by daytime lapses into sleep, or an overwhelming need to sleep that persists even with adequate or prolonged nighttime sleep. Additionally, those with IH have extreme difficulty waking, otherwise known as “sleep inertia,” and suffer from severe and debilitating brain fog. No orexin deficiency has been observed in cerebrospinal fluid (“CSF”) from individuals with IH.

Corporate Information

Centessa Pharmaceuticals plc is registered with the Registrar of Companies in England and Wales under number 12973576. Our UK registered office is at 3rd Floor, 1 Ashley Road, Altrincham, Cheshire, United Kingdom, WA14 2DT and our US headquarters is at One Federal Street, 38th Floor, Boston, MA 02110 and our phone number in the US is +1.617.468.5770. Our website address is http://www.centessa.com. The information contained on, or that can be accessed through, our website is not incorporated by reference in this prospectus supplement and you should not consider it part of this prospectus.

Our UK business is operated by Centessa Pharmaceuticals (UK) Limited, (“CPUK”), (formerly Centessa Limited) directly and, in respect of the SerpinPC program, through its wholly owned UK subsidiary, ApcinteX Limited. In mid-2023, we implemented a corporate consolidation of our UK businesses in order to simplify our administrative operations, obtain operational efficiencies and generate administrative cost savings and improve the overall control environment. This has resulted in the business and assets of our UK subsidiaries, Z Factor Limited, Centessa Pharmaceuticals (Morphogen-IX) Limited, Capella Bioscience Ltd, LockBody Therapeutics Ltd, Inexia Limited, Centessa Pharmaceuticals (Orexia) Limited and Janpix Limited being transferred to CPUK. Subsequently, on December 26, 2023, Inexia Limited, Janpix Limited, Ultrahuman Two Limited and Ultrahuman Four Limited were dissolved using the voluntary strike off procedure in sections 1003 to 1011 of the UK Companies Act 2006. We intend to dissolve Z Factor Limited, Centessa Pharmaceuticals (Morphogen-IX) Limited, Capella Bioscience Ltd, LockBody Therapeutics Ltd, and Centessa Pharmaceuticals (Orexia) Limited over the coming months using the voluntary strike off procedure in sections 1003 to 1011 of the UK Companies Act 2006. CPUK is a wholly owned subsidiary of Centessa Pharmaceuticals plc. CPUK was incorporated in 2020 under the laws of England and Wales with primary operations in the United Kingdom. ApcinteX Limited was incorporated in 2014 under the laws of England and Wales with primary operations in the United Kingdom. Our U.S. subsidiaries are Centessa Pharmaceuticals Holdings, Inc., incorporated in 2022 under the laws of Delaware, Centessa Biosciences, Inc. (formerly known as Palladio Biosciences, Inc.), incorporated in 2015 under the laws of Delaware and Centessa Pharmaceuticals LLC (formerly known as Centessa Pharmaceuticals, Inc.), incorporated in 2020 under the laws of Delaware. We refer to CPUK, ApcinteX Limited, Z Factor Limited, Centessa Pharmaceuticals (Morphogen-IX) Limited, Capella Bioscience Ltd, LockBody Therapeutics Ltd, and Centessa Pharmaceuticals (Orexia) Limited, Centessa Pharmaceuticals Holdings, Inc., Centessa Biosciences, Inc. and Centessa Pharmaceuticals LLC as the “Centessa Subsidiaries”.

Implications of Being an Emerging Growth Company and a Smaller Reporting Company

We are an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act (JOBS Act) enacted in April 2012. For so long as we remain an emerging growth company, we are permitted and intend to rely on certain exemptions from various public company reporting requirements, including not being required to have our internal control over financial reporting audited by our independent registered public accounting firm pursuant to Section 404(b) of the Sarbanes-Oxley Act of 2002, reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements, exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and any golden parachute payments not previously approved.

We will remain an emerging growth company until the earlier to occur of (1) December 31, 2026, (2) the last day of the fiscal year in which we have total annual gross revenues of at least $1.235 billion, (3) the last day of the

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fiscal year in which we are deemed to be a “large accelerated filer,” under the rules of the SEC which means the market value of our equity securities that is held by non-affiliates exceeds $700 million as of the prior June 30th, and (4) the date on which we have issued more than $1.0 billion in non-convertible debt during the prior three-year period.

In addition, the JOBS Act provides that an emerging growth company can take advantage of an extended transition period for complying with new or revised accounting standards. This provision allows an emerging growth company to delay the adoption of some accounting standards until those standards would otherwise apply to private companies. We have elected to utilize the extended transition period and, as a result, will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for private companies.

We also qualify as a “smaller reporting company” and will continue to qualify as a smaller reporting company for so long as the market value of our ordinary shares held by non-affiliates is below $250 million (or $700 million if our annual revenue is less than $100 million) as of June 30 in any given year, which allows us to take advantage of many of the same exemptions from disclosure requirements, including reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements.

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THE OFFERING

ADSs offered by us: $150,000,000 of ordinary shares represented by ADSs.

Option to purchase additional ADSs from us: We have granted the underwriters an option for a period of 30 days to purchase up to an additional $22,500,000 of ADSs from us at the public offering price, less the underwriting discounts and commissions.

Total ordinary shares (including ordinary shares represented by ADSs) to be outstanding immediately following this offering:      ordinary shares (or       ordinary shares if the underwriters’ option to purchase additional ADSs from us is exercised in full).

American Depositary Shares (ADSs): Each ADS represents one ordinary share with a nominal value of £0.002 per ordinary share. You will have the rights of an ADS holder as provided in the deposit agreement among us, the Depositary and all holders and beneficial owners of ADSs issued thereunder. To better understand the terms of the ADSs, you should carefully read the section in the accompanying prospectus titled “Description of American Depositary Shares.” We also encourage you to read the deposit agreement, which is filed as an exhibit to the registration statement that includes this prospectus supplement.

Depositary: Citibank, N.A.

Use of Proceeds: We intend to use the net proceeds from this offering together with our existing cash, cash equivalents, and short-term investments to fund the continued development of our product candidates, as well as for general corporate purposes. See the section entitled “Use of Proceeds.”

Risk Factors: Investing in our securities involves a high degree of risk. See the section entitled “Risk Factors” on page S-8 of this prospectus supplement and under similar headings in other documents incorporated by reference into this prospectus supplement and the accompanying prospectus.

The Nasdaq Global Select Market Symbol: “CNTA”

All information in this prospectus supplement related to the number of our ordinary shares to be outstanding immediately after this offering is based on 113,177,764 of our ordinary shares outstanding as of June 30, 2024. The number of ordinary shares outstanding as of June 30, 2024 excludes:

• 18,764,967 ordinary shares issuable upon the exercise of share options as of June 30, 2024, at a weighted-average exercise price of $7.32 per share;

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• 196,985 unvested restricted share awards, including 56,531 restricted share awards that vested as of the date of this prospectus supplement;

• 2,164,448 ordinary shares reserved for the vesting and settlement of outstanding restricted share units as of June 30, 2024, including 26,009 ordinary shares issued upon vesting and settlement of restricted share units as of the date of this prospectus supplement;

• 9,327,920 ordinary shares reserved for future issuance under our equity incentive plans as of June 30, 2024, as well as any future increases in the number of ordinary shares reserved for issuable under such plans; and

• 2,708,415 ordinary shares reserved for future issuance under our employee share purchase plan as of June 30, 2024, as well as any future increases in the number of ordinary shares reserved for issuance under such plan.

Unless otherwise stated, all information contained in this prospectus assumes no exercise of share options or settlement of restricted stock units after June 30, 2024 (other than as described above), and no exercise of the underwriters’ option to purchase additional ADSs.

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RISK FACTORS

Investing in the ADSs and our ordinary shares involves a high degree of risk. You should carefully consider the risks and uncertainties described in the following risk factors as well as the other information contained in this prospectus supplement, the accompanying prospectus and in the documents incorporated by reference into this prospectus supplement and the accompanying prospectus before making an investment decision. Our business, financial condition or results of operations could be materially adversely affected by the materialization of any of these risks. The trading price of the ADSs could decline due to the materialization of any of these risks, and you may lose all or part of your investment. This prospectus supplement, the accompanying prospectus and the documents incorporated herein and therein by reference also contain forward-looking statements that involve risks and uncertainties. See the section titled “Special Note Regarding Forward-Looking Statements.” Actual results could differ materially from those anticipated in these forward-looking statements as a result of certain factors, including the risks described in the documents incorporated herein by reference, including our most recent annual report on Form 10-K for the year ended December 31, 2024, as updated by our Quarterly Reports on From 10-Q for the quarters ended March 31, 2024 and June 30, 2024, which are on file with the SEC and are incorporated by reference into this prospectus supplement and the accompanying prospectus, other documents that are incorporated by reference into this prospectus supplement and the accompanying prospectus, and other documents we file with the SEC that are deemed incorporated by reference into this prospectus supplement and the accompanying prospectus. The risks and uncertainties we have described are not the only ones facing our company. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also affect our business, financial condition, and results of operations.

Risks Related to this Offering

If you purchase our securities in this offering, you will experience immediate and substantial dilution in investment. You will experience further dilution if we issue additional equity securities in future financing transactions.

Since the offering price per ADS is higher than the net tangible book value per ADS or ordinary share, you will suffer immediate and substantial dilution in the net tangible book value of the ADSs that you purchase in this offering. As a result, investors purchasing ADSs in this offering will incur immediate dilution of approximately $    per ADS, based upon the offering price of $    per ADS, and our as adjusted net tangible book value as of June 30, 2024 after giving effect to this offering, including the issuance of       ADSs for an aggregate purchase price of $   . See the section entitled “Dilution” below for a more detailed discussion of the dilution you will incur if you purchase ADSs in this offering.

In addition, we have a significant number of share options and restricted share units outstanding and reserved for future issuance. To the extent that these vest or have been or may be exercised, investors purchasing in this offering may experience further dilution.

We may seek additional capital through a variety of means, including through public or private equity, debt financings or other sources, including up-front payments (including by way of investments in our securities) and milestone payments from strategic collaborations. To the extent we raise additional capital in the future and we issue additional ordinary shares, including ordinary shares represented by ADSs, or securities convertible or exchangeable for our ordinary shares, our then existing shareholders may experience dilution and the new securities may have rights senior to those of our ADSs offered in this offering. If we raise additional funds through up-front payments (including by way of investments in our securities) or milestone payments pursuant to strategic collaborations with third parties, we may have to relinquish valuable rights to our product candidates, or grant licenses on terms that are not favorable to us. In addition, we may seek additional capital due to favorable market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans.

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We, our executive officers and directors and certain of our shareholders have entered into lock-up agreements with the underwriters under which we and they have agreed, subject to specific exceptions described in the section entitled “Underwriters,” not to sell, directly or indirectly, any ADSs or ordinary shares without the permission of the underwriters for a period of 60 days following the date of this prospectus supplement. We refer to such period as the lock-up period. When the lock-up period expires, we and our executive officers and directors and these shareholders, as applicable, will be able to sell our ADSs in the public market. In addition, the underwriters may, in their sole discretion, release all or some portion of the ADSs subject to lock-up agreements at any time and for any reason. Sales of a substantial number of such ADSs upon expiration of the lock-up, the perception that such sales may occur, or early release of these agreements, could cause our market price to fall or make it more difficult for you to sell your ADS at a time and price that you deem appropriate.

You may experience future dilution as a result of future equity offerings.

To raise additional capital, we may in the future offer additional ADSs or other securities convertible into or exchangeable for our ordinary shares at prices that may not be the same as the price per share in this offering. We may sell shares or other securities in any other offering at a price per share that is less than the price per share paid by investors in this offering, and investors purchasing shares or other securities in the future could have rights superior to existing holders of our ADSs. The price per share at which we sell additional ADSs, or securities convertible or exchangeable into ADSs, in future transactions may be higher or lower than the price per share paid by investors in this offering.

We have broad discretion in the use of the net proceeds from this offering and may not use them effectively.

Our management will have broad discretion in the application of the net proceeds from this offering, if any, including for any of the purposes described in the section entitled “Use of Proceeds,” and across any of our programs and you will not have the opportunity as part of your investment decision to assess whether the net proceeds are being used appropriately. Because of the number and variability of factors that will determine our use of the net proceeds from this offering, their ultimate use may vary substantially from their currently intended use. The failure by our management to apply these funds effectively could harm our business. Pending their use, we may invest the net proceeds from this offering in a variety of capital preservation instruments, including short-term, investment-grade, interest-bearing instruments and U.S. government securities. These investments may not yield a favorable return to our shareholders.

Holders of ADSs are not treated as holders of our ordinary shares.

By participating in this offering you will become a holder of ADSs representing ordinary shares in a company incorporated under English law. Holders of ADSs are not treated as holders of our ordinary shares, unless they withdraw the ordinary shares represented by their ADSs in accordance with the deposit agreement and applicable laws and regulations. The depositary is the holder of the ordinary shares represented by the ADSs. Holders of ADSs therefore do not have any rights as holders of our ordinary shares, other than the rights that they have pursuant to the deposit agreement.

Holders of ADSs may be subject to limitations on the transfer of their ADSs and the withdrawal of the underlying ordinary shares.

ADSs are transferable on the books of the depositary. However, the depositary may close its books at any time or from time to time when it deems expedient in connection with the performance of its duties. The depositary may refuse to deliver, transfer or register transfers of ADSs generally when our books or the books of the depositary are closed, or at any time if we or the depositary think it is advisable to do so because of any requirement of law, government or governmental body, or under any provision of the deposit agreement, or for any other reason, subject to the right of ADS holders to cancel their ADSs and withdraw the underlying ordinary shares. Temporary delays in the cancellation of ADSs and withdrawal of the underlying ordinary shares may arise

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because the depositary has closed its transfer books or we have closed our transfer books, the transfer of ordinary shares is blocked to permit voting at a shareholders meeting or we are paying a dividend on our ordinary shares.

In addition, ADS holders may not be able to cancel their ADSs and withdraw the underlying ordinary shares when they owe money for fees, taxes and similar charges and when it is necessary to prohibit withdrawals in order to comply with any laws or governmental regulations that apply to ADSs or to the withdrawal of ordinary shares or other deposited securities.

The market price of ADSs may be adversely affected by market conditions affecting the stock markets in general, including price and trading fluctuations on The Nasdaq Global Select Market.

Market conditions may result in volatility in the level of, and fluctuations in, market prices of stocks generally and, in turn, ADSs and sales of substantial amounts of ADSs in the market, in each case being unrelated or disproportionate to changes in our operating performance. Concerns over global stability and economic conditions in the U.S. and abroad have contributed to the extreme volatility of the markets, which may have an effect on the market price of ADSs.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement and the accompanying prospectus, including the documents incorporated by reference herein and therein, and any free writing prospectus that we have authorized for use in connection with this offering, contain express or implied forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Exchange Act that involve substantial risks and uncertainties. In some cases, forward-looking statements may be identified by the words “may,” “might,” “will,” “could,” “would,” “should,” “expect,” “intend,” “plan,” “objective,” “anticipate,” “believe,” “estimate,” “predict,” “potential,” “continue,” “ongoing,” “aim,” “seek,” “strive,” or the negative of these terms, or other comparable terminology intended to identify statements about the future. These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, levels of activity, performance or achievements to be materially different from the information expressed or implied by these forward-looking statements. The forward-looking statements and opinions contained in this prospectus supplement are based upon information available to our management as of the date of this prospectus supplement, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Forward-looking statements contained in this prospectus supplement include, but are not limited to, statements about:

• the initiation, timing, progress and results (preliminary, interim or final) of our preclinical studies and clinical trials, and our research and development programs including SerpinPC, LB101, other LockBody candidates, the LockBody technology platform, ORX750, ORX142 and other orexin agonist molecules;

• our ability to execute our research and clinical development plans and our expectations on and the timing thereof;

• our expectations and ability to advance our pipeline and product candidates into, and successfully complete, clinical trials;

• our ability to identify screen, recruit and maintain a sufficient number of, or any, subjects in our existing and anticipated studies or clinical trials including PRESent-5, the observational feeder study, PRESent-2 and PRESent-3 and studies or trials of LB101, and any other LockBody candidates, ORX750 and other orexin agonist molecules;

• our ability to differentiate SerpinPC, LB101, ORX750, other orexin agonist molecules, and other LockBody candidates from other treatment options;

• the development and therapeutic potential of SerpinPC, LB101, other LockBody candidates, the LockBody technology platform, ORX750 and other orexin agonist molecules;

• our expectations relating to the further clinical development of ORX750 the exploration of higher doses in the Phase 1 first-in-human, clinical trial of ORX750, the initiation of Phase 2 study of ORX750, including the predicted timing of enrollment, the predicted efficacious doses of ORX750 and our ability to successfully conduct our clinical development of ORX750;

• whether preclinical and initial clinical results of our programs, including ORX750, SerpinPC and LB101, will be predictive of results of further clinical trials;

• the safety and tolerability profile of our product candidates;

• our reliance on the success of our product candidates and our pipeline programs;

• our ability to discover and develop transformational medicines for patients including identifying and advancing additional product candidates into clinical development;

• our ability to become the partner of choice to attract founder-subject matter experts with high conviction programs;

• the timing or likelihood of regulatory filings and approvals;

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• the impact of inflation on increasing costs of labor, research, manufacturing and clinical trial expenses;

• the impact of the Russia-Ukraine war, the Middle East conflict(s) and tensions in U.S.-China relations on our business and operations;

• the commercialization of our product candidates, if approved;

• our ability to develop sales and marketing capabilities;

• the pricing, coverage and reimbursement of our product candidates, if approved;

• the implementation of our business model, strategic plans for our business, product candidates and technology;

• the scope of protection we are able to establish and maintain for intellectual property rights covering our product candidates and technology;

• our ability to operate our business without infringing the intellectual property rights and proprietary technology of third parties;

• cost associated with prosecuting and maintaining our intellectual property and with defending intellectual property infringement, product liability and other claims;

• legal and regulatory developments in the United States, the European Union, the United Kingdom and other jurisdictions;

• estimates of our expenses, future revenues, capital requirements and our needs for additional financing;

• the potential benefits of strategic collaboration agreements and our ability to negotiate and enter into strategic arrangements;

• our ability to identify collaboration opportunities and to establish and maintain collaborations;

• our ability to judiciously manage and allocate our cash;

• our expectations on our anticipated cash runway;

• our ability to obtain additional funding;

• our ability to fulfill our obligations under the Note Purchase Agreement, as amended, with Three Peaks Capital Solutions Aggregator Fund (the “Purchaser”), and Cocoon SA LLC (the “Purchaser Agent”), an affiliate of Oberland Capital Management LLC (collectively “Oberland Capital”);

• the rate and degree of market acceptance of any approved products;

• developments relating to our competitors and our industry, including competing therapies and our ability to respond to such developments;

• our ability to effectively manage our anticipated growth;

• our ability to attract and retain qualified employees and key personnel;

• our expectations regarding the period during which we qualify as a smaller reporting company and as an emerging growth company under the JOBS Act;

• statements regarding future revenue, hiring plans, expenses, capital expenditures, capital requirements and share performance;

• our expected use of proceeds from the offering to which this prospectus supplement relates;

• the future trading price of the ADSs and impact of securities analysts’ reports on these prices; and

• other risks and uncertainties, including those listed under the caption “Risk Factors.”

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You should refer to the risks and uncertainties described in the section entitled “Risk Factors” contained in this prospectus supplement, the accompanying prospectus and any related free writing prospectus we authorize for use in connection with this offering, and under similar headings in the other documents that are incorporated by reference into this prospectus supplement and the accompanying prospectus, for a discussion of important factors that may cause our actual results to differ materially from those expressed or implied by our forward-looking statements. Given these risks, uncertainties and other factors, many of which are beyond our control, we cannot assure you that the forward-looking statements in this prospectus supplement and the accompanying prospectus will prove to be accurate, and you should not place undue reliance on these forward-looking statements. Furthermore, if our forward-looking statements prove to be inaccurate, the inaccuracy may be material. In light of the significant uncertainties in these forward-looking statements, you should not regard these statements as a representation or warranty by us or any other person that we will achieve our objectives and plans in any specified time frame, or at all.

Except as required by law, we assume no obligation to update these forward-looking statements publicly, or to revise any forward-looking statements to reflect events or developments occurring after the date of this prospectus supplement, even if new information becomes available in the future.

In addition, statements that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this prospectus supplement, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all relevant information. These statements are inherently uncertain and investors are cautioned not to unduly rely upon these statements.

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USE OF PROCEEDS

We expect to receive approximately $    million in net proceeds from the sale of      ADSs offered by us in this offering (or approximately $    million if the underwriters exercise their option to purchase       additional ADSs in full), after deducting underwriting discounts and commissions and estimated offering expenses payable by us.

We intend to use the net proceeds from the offering, together with our existing cash, cash equivalents, and short-term investments, to fund the continued development of our product candidates, as well as for general corporate purposes. Pending our use of the net proceeds from this offering, we plan to invest the net proceeds in interest-bearing cash accounts and direct or guaranteed obligations of the U.S. government.

The expected use of the net proceeds from the offering represents our intentions based upon our current plans and business conditions. As of the date of this prospectus supplement, we cannot predict with any certainty all of the particular uses for the net proceeds or the amounts that we will actually spend on the uses set forth above. We may use a portion of the net proceeds for the acquisition of, or investment in, technologies, solutions or businesses that complement our business, although we have no present commitments or agreements.

As of June 30, 2024, we had cash, cash equivalents and short-term investments of $294.8 million.

Following this offering, we expect our existing cash, cash equivalents and short-term investments will enable us to fund our operating expenses and capital expenditure requirements into mid-2027. We have based this estimate on assumptions that may prove to be wrong, and we could use our available capital resources sooner than we currently expect.

The amounts and timing of our clinical expenditures and the extent of clinical development may vary significantly depending on numerous factors, including the status, results and timing of our current preclinical studies and clinical trials we may commence in the future, product approval process with the FDA and other regulatory agencies, our current collaborations and any new collaborations we may enter into with third parties and any unforeseen cash needs. As a result, our management will retain broad discretion over the allocation of the net proceeds from this offering.

The expected net proceeds of this offering will not be sufficient for us to fund any of our product candidates through regulatory approval, and we will need to raise substantial additional capital to complete the development and commercialization of our product candidates.

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DILUTION

Our net tangible book value as of June 30, 2024 was $284.7 million, or $2.52 per ordinary share, equivalent to $2.52 per ADS. Net tangible book value per share is determined by dividing our total tangible assets, less total liabilities, by the number of ordinary shares outstanding as of June 30, 2024. Dilution with respect to net tangible book value per ADS represents the difference between the amount per ADS paid by purchasers of ADSs in this offering and the net tangible book value per ordinary share immediately after this offering.

After giving effect to the sale of     ADSs in this offering at a public offering price of $    per ADS, and after deducting estimated offering commissions and offering expenses payable by us, our as adjusted net tangible book value as of June 30, 2024 would have been approximately $    million, or $    per ordinary share. This represents an immediate increase in net tangible book value of $    per ADS or ordinary share to existing shareholders and holders of our ADSs and immediate dilution of $    per ADS or ordinary share to investors purchasing ADSs in this offering at the public offering price.

The following table illustrates this dilution on a per share basis:

Public offering price per ADS			$
Net tangible book value per ADS or ordinary share as of June 30, 2024	$	2.52
Increase in net tangible book value per ADS or ordinary share attributable to new investors purchasing ADSs in this offering
As adjusted net tangible book value per ADS or ordinary share as of June 30, 2024, after giving effect to this offering
Dilution per ADS or ordinary share to new investors purchasing ADSs in this offering			$

If the underwriters exercise in full their option to purchase up to       additional ADSs at the public offering price of $    per ADS, the as adjusted net tangible book value after this offering would be $    per ordinary share, representing an increase in net tangible book value of $    per ADS or ordinary share to existing shareholders and holders of our ADS and immediate dilution in net tangible book value of $    per ADS to investors purchasing our ADSs in this offering at the public offering price.

The above discussion and table are based on 113,177,764 ordinary shares outstanding as of June 30, 2024, and excludes:

• 18,764,967 ordinary shares issuable upon the exercise of share options as of June 30, 2024, at a weighted-average exercise price of $7.32 per share;

• 196,985 unvested restricted share awards, including 56,531 restricted share awards that vested as of the date of this prospectus supplement;

• 2,164,448 ordinary shares reserved for the vesting and settlement of outstanding restricted share units as of June 30, 2024, including 26,009 ordinary shares issued upon vesting and settlement of restricted share units as of the date of this prospectus supplement;

• 9,327,920 ordinary shares reserved for future issuance under our equity incentive plans as of June 30, 2024, as well as any future increases in the number of ordinary shares reserved for issuable under such plans; and

• 2,708,415 ordinary shares reserved for future issuance under our employee share purchase plan as of June 30, 2024, as well as any future increases in the number of ordinary shares reserved for issuance under such plan.

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To the extent that options or restricted stock units outstanding as of June 30, 2024 have vested or have been or may be exercised or other ordinary shares have or may be issued, investors purchasing our ADSs in this offering may experience further dilution. In addition, we may choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our shareholders.

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UNDERWRITING

We and the underwriters named below have entered into an underwriting agreement with respect to the ADSs being offered. Subject to certain conditions, each underwriter has severally agreed to purchase the number of ADSs indicated in the following table. Goldman Sachs & Co. LLC and Leerink Partners LLC are the representatives of the underwriters.

Underwriters	Number of ADSs
Goldman Sachs & Co. LLC
Leerink Partners LLC
Evercore Group L.L.C.
Guggenheim Securities, LLC
BMO Capital Markets Corp.
Total

The underwriters are committed to take and pay for all of the ADSs being offered, if any are taken, other than the ADSs covered by the option described below unless and until this option is exercised.

The underwriters have an option to buy up to an additional   ADSs from us to cover sales by the underwriters of a greater number of ADSs than the total number set forth in the table above. They may exercise that option for 30 days. If any ADSs are purchased pursuant to this option, the underwriters will severally purchase ADSs in approximately the same proportion as set forth in the table above.

The following table shows the per ADS and total underwriting discounts and commissions to be paid to the underwriters by us. Such amounts are shown assuming both no exercise and full exercise of the underwriters’ option to purchase    additional ADSs.

Paid by Us	No Exercise		Full Exercise
Per ADS	$		$
Total	$		$

We estimate that our total expenses of the offering, excluding underwriting discounts and commissions, will be approximately $   . We have agreed to reimburse the underwriters for expenses of up to $25,000 related to the clearance of this offering with the Financial Industry Regulatory Authority, Inc.

ADSs sold by the underwriters to the public will initially be offered at the initial public offering price set forth on the cover of this prospectus supplement. Any ADSs sold by the underwriters to securities dealers may be sold at a discount of up to $    per ADS from the public offering price. After the initial offering of the ADSs, the representatives may change the offering price and the other selling terms. The offering of the ADSs by the underwriters is subject to receipt and acceptance and subject to the underwriters’ right to reject any order in whole or in part.

We, our executive officers, directors and certain of our shareholders have agreed with the underwriters, subject to certain exceptions, not to dispose of or hedge any of their ADSs, ordinary shares (together, “Securities”) or securities convertible into or exchangeable for Securities during the period from the date of this prospectus supplement continuing through the date 60 days after the date of this prospectus supplement.

The restrictions described in the immediately preceding paragraph do not apply to our directors, executive officers and certain of our shareholders with respect to:

(a) transactions relating to Securities acquired in this offering or in open market transactions after the completion of this offering;

(b) transfers of Securities or any security convertible into or exercisable or exchangeable for Securities as a bona fide gift;

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(c) distributions of Securities or any security convertible into or exercisable or exchangeable for Securities to limited partners, shareholders, members, general partners, managers, directors, officers or employees or trust beneficiaries of the lock-up party or of the lock-up party’s affiliates (as defined in Rule 405 promulgated under the Securities Act of 1933, as amended) or to any investment fund or other entity that is directly or indirectly controlling, controlled by, managing or managed by or under common control with the lock-up party or the lock-up party’s affiliates in a transaction not involving a disposition for value;

(d) the establishment of a trading plan pursuant to Rule 10b5-1 under the Exchange Act for the transfer of Securities, provided that such plan does not provide for the transfer of Securities during the lock-up period; provided, further, that no public announcement, report or filing under the Exchange Act, or any other public filing, report or announcement, shall be voluntarily made regarding the establishment of such plan during the lock-up period, and if any such filing, report or announcement shall be legally required during the lock-up period, such filing, report or announcement shall clearly indicate in the footnotes thereto that that none of the securities subject to such plan may be transferred, sold or otherwise disposed of pursuant to such plan until after the expiration of the lock-up period;

(e) transfers or dispositions of Securities or other securities to any member of the immediate family of the lock-up party or any trust for the direct or indirect benefit of the lock-up party or the immediate family of the lock-up party in a transaction not involving a disposition for value;

(f) transfers or dispositions of Securities or any security convertible into or exercisable or exchangeable for Securities to any corporation, partnership, limited liability company or other entity that is directly or indirectly controlling, controlled by, managing or managed by or under common control with the lock-up party or the lock-up party’s affiliates; including, for the avoidance of doubt, transfers or distributions of Securities or any securities convertible into or exercisable or exchangeable for Securities to a fund managed by the same manager or managing member or general partner or management company or by an entity controlling, controlled by, or under common control with such manager or managing member or general partner or management company as the lock-up party or who shares a common investment advisor with the lock-up party, in a transaction not involving a disposition for value;

(g) transfers or dispositions of our Securities (x) by will, other testamentary document or intestate succession to the legal representative, heir, beneficiary or a member of the immediate family of the lock-up party upon the death of the lock-up party, or (y) by operation of law pursuant to a domestic order or negotiated divorce settlement;

(h) transfers or dispositions of Securities or any other security convertible into or exercisable or exchangeable for Securities to us pursuant to any contractual arrangement in effect prior to the date hereof and disclosed to the underwriters that provides for our repurchase of the lock-up party’s Securities or in connection with the termination of the lock-up party’s employment with or service to the Company, provided that the repurchase price for any such Securities shall not exceed the original purchase price paid by the lock-up party to us for such securities, provided further that such contractual arrangement is disclosed in this prospectus supplement or filed as an exhibit to this prospectus supplement or a document incorporated by reference herein;

(i) (x) the exercise of any option, warrant, (y) the vesting of restricted stock or (z) the settlement of restricted stock units described in this prospectus supplement and outstanding as of the date of this prospectus supplement for, Securities, provided that any such Securities received by the lock-up party shall be subject to the terms of this letter; provided, further, that no public filing or public announcement under Section 16(a) of the Exchange Act shall be voluntarily made and any public filing or public announcement under Section 16(a) of the Exchange Act required during the lock-up period in connection with the exercise of such share option or warrant shall clearly indicate in the footnotes thereto or comments section thereof that the filing relates to the exercise of a share option or warrant, as the case may be, that no Securities were sold by the reporting person and that the Securities received upon exercise of the share option or warrant are subject to a lock-up agreement with the underwriters of this offering;

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(j) transfers or dispositions (including through a “cashless” exercise or on a “net exercise” basis) of Securities or any security convertible into Securities to us in connection with the exercise of any option, vesting of restricted stock, or settlement of any restricted stock unit (including to satisfy withholding obligations or the payment of taxes in connection therewith); provided that any such Securities received by the lock-up party shall be subject to the terms of this letter; provided, further, that no public filing or public announcement under Section 16(a) of the Exchange Act shall be voluntarily made and any public filing or public announcement under Section 16(a) of the Exchange Act required during the lock-up period in connection with such transfer or disposition shall clearly indicate in the footnotes thereto or comments section thereof that the filing relates to the exercise of any option, vesting of restricted stock, or settlement of restricted stock unit, as the case may be, that no Securities were sold by the reporting person and that the Securities received upon exercise of any option, vesting of restricted stock, or settlement of any restricted stock unit are subject to a lock-up agreement with the underwriters of this offering;

(k) the sale of Securities pursuant to a 10b5-1 plan that complies with Rule 10b5-1 and that exists on the date such lock-up agreement was entered into, if any; provided that the existence and details of such 10b5-1 plan were communicated to the underwriters and such 10b5-1 plan will not be amended or otherwise modified during the lock-up period; provided further that any Form 4 or Form 5 required to be filed under the Exchange Act if the lock-up party is subject to Section 16 reporting with respect to the Company under the Exchange Act will indicate by footnote that such sale was made under the circumstances described in this clause; and provided further that no other filing under the Exchange Act or other public announcement shall be required or shall be made voluntarily in connection with such sale during the lock-up period; or

(l) transfers or dispositions of Securities or such other securities pursuant to a bona fide tender offer for shares of our share capital, merger, consolidation or other similar transaction made to all holders of our securities involving a change of control of the Company (including without limitation, the entering into of any lock-up, voting or similar agreement pursuant to which the lock-up party may agree to transfer, sell, tender or otherwise dispose of Securities or other securities in connection with such transaction) that has been approved by our board of directors, provided that, in the event that such change of control transaction is not consummated, this clause (l) shall not be applicable and the lock-up party’s shares and other securities shall remain subject to the restrictions contained in such lock-up agreement; provided that, in the case of any transfer or distribution pursuant to clauses (b), (c), (e), (f) or (g), each transferee or distributee shall enter into a lock-up agreement with the underwriters; provided further that in the case of any transfer or distribution pursuant to clauses (a), (b), (c), (e), (f), (g) or (h), no public announcement or public filing under Section 16(a) of the Exchange Act relating to such transfer or distribution shall be required or shall be voluntarily made during the lock-up period (other than, in the case of a transfer or other disposition pursuant to clause (b) above, any Form 4 or Form 5 required to be filed under the Exchange Act if the lock-up party is subject to Section 16 reporting with respect to the Company under the Exchange Act and indicating by footnote disclosure or otherwise the nature of the transfer or disposition).

The restrictions on transfers or other dispositions by us described above do not apply to:

(a) the ADSs to be sold hereunder, (b) the issuance by us of Securities upon the exercise of an option or warrant, settlement of restricted stock units, or the conversion of a security outstanding on the date hereof as described herein, (c) grants of options, restricted shares, restricted stock units or other equity awards and the issuance of Securities or securities convertible or exercisable for Securities to our employees, officers, directors, advisors or consultants pursuant to our equity incentive plans as described herein or pursuant to the grant of an inducement grant award, as permitted by Nasdaq Stock Market Rule 5635; provided further, that any executive officers (as defined in Section 16 of the Exchange Act) or directors who are recipients of any such Securities and securities issued pursuant to this clause (c) during the lock-up period, shall enter into a lockup agreement with the underwriters, (d) the filing of one or more registration statements, including on Form S-8 or otherwise, to register Securities issuable pursuant to any equity incentive plans described herein, (e) Securities or any securities convertible into or exercisable or exchangeable for Securities, or the entrance into an agreement to

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issue such securities, in connection with any merger, joint venture, strategic alliance, commercial, debt financing, collaborative transaction or the acquisition or license of the business, property, technology or other assets of another individual or entity or the assumption of an equity incentive plan in connection with a merger or acquisition; provided that the aggregate number of Securities or any securities convertible into, or exercisable or exchangeable for, Securities that we may issue or agree to issue pursuant to this clause (e) shall not exceed 10% of the total outstanding Securities, immediately following the issuance of the ADSs, and provided further, that the recipients of any such Securities and securities issued pursuant to this clause (e) during the lock-up period shall enter into a lockup agreement with the underwriters, or (f) facilitating the establishment of a trading plan on behalf of one of our shareholders, employees, officers, directors, advisors or consultants pursuant to Rule 10b5-1 under the Exchange Act for the transfer of Securities, provided that (i) such plan does not provide for the transfer of Securities during the lock-up period and (ii) to the extent a public announcement or filing under the Exchange Act (or the equivalent thereof in any non-U.S. jurisdiction), if any, is required of or voluntarily made by us regarding the establishment of such plan, such announcement or filing shall include a statement to the effect that no transfer of Securities may be made under such plan during the lock-up period.

Our ADSs are listed on The Nasdaq Global Select Market under the symbol “CNTA.”

In connection with the offering, the underwriters may purchase and sell our ADSs in the open market. These transactions may include short sales, stabilizing transactions and purchases to cover positions created by short sales. Short sales involve the sale by the underwriters of a greater number of ADSs than they are required to purchase in the offering, and a short position represents the amount of such sales that have not been covered by subsequent purchases. A “covered short position” is a short position that is not greater than the amount of additional ADSs for which the underwriters’ option described above may be exercised. The underwriters may cover any covered short position by either exercising their option to purchase additional ADSs or purchasing ADSs in the open market. In determining the source of ADSs to cover the covered short position, the underwriters will consider, among other things, the price of ADSs available for purchase in the open market as compared to the price at which they may purchase additional ADSs pursuant to the option described above. “Naked” short sales are any short sales that create a short position greater than the amount of additional ADSs for which the option described above may be exercised. The underwriters must cover any such naked short position by purchasing ADSs in the open market. A naked short position is more likely to be created if the underwriters are concerned that there may be downward pressure on the price of our ADSs in the open market after pricing that could adversely affect investors who purchase in the offering. Stabilizing transactions consist of various bids for or purchases of our ADSs made by the underwriters in the open market prior to the completion of the offering.

The underwriters may also impose a penalty bid. This occurs when a particular underwriter repays to the underwriters a portion of the underwriting discount received by it because the representatives have repurchased ADSs sold by or for the account of such underwriter in stabilizing or short covering transactions.

Purchases to cover a short position and stabilizing transactions, as well as other purchases by the underwriters for their own accounts, may have the effect of preventing or retarding a decline in the market price of our ADSs, and together with the imposition of the penalty bid, may stabilize, maintain or otherwise affect the market price of the ADSs. As a result, the price of our ordinary shares may be higher than the price that otherwise might exist in the open market. The underwriters are not required to engage in these activities and may end any of these activities at any time. These transactions may be effected on The Nasdaq Global Select Market, in the over-the-counter market or otherwise.

We have agreed to indemnify the several underwriters against certain liabilities, including liabilities under the Securities Act of 1933, as amended.

The underwriters and their respective affiliates are full service financial institutions engaged in various activities, which may include sales and trading, commercial and investment banking, advisory, investment

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management, investment research, principal investment, hedging, market making, brokerage and other financial and non-financial activities and services. Certain of the underwriters and their respective affiliates have provided, and may in the future provide, a variety of these services to us and to persons and entities with relationships with us, for which they received or will receive customary fees and expenses. For example, Leerink Partners LLC is the sales agent under a Sales Agreement, dated as of January 27, 2023, with us.

In the ordinary course of their various business activities, the underwriters and their respective affiliates, officers, directors and employees may purchase, sell or hold a broad array of investments and actively trade securities, derivatives, loans, commodities, currencies, credit default swaps and other financial instruments for their own account and for the accounts of their customers, and such investment and trading activities may involve or relate to our assets, securities and/or instruments (directly, as collateral securing other obligations or otherwise) and/or persons and entities with relationships with us. The underwriters and their respective affiliates may also communicate independent investment recommendations, market color or trading ideas and/or publish or express independent research views in respect of such assets, securities or instruments and may at any time hold, or recommend to clients that they should acquire, long and/or short positions in such assets, securities and instruments.

European Economic Area

In relation to each Member State of the European Economic Area (each a “Relevant Member State”), no ADSs have been offered or will be offered pursuant to the offering to the public in that Relevant Member State prior to the publication of a prospectus in relation to the ADSs which has been approved by the competent authority in that Relevant Member State or, where appropriate, approved in another Relevant Member State and notified to the competent authority in that Relevant Member State, all in accordance with the Prospectus Regulation, except that the ADSs may be offered to the public in that Relevant Member State at any time:

(a) to any legal entity which is a qualified investor as defined under Article 2 of the Prospectus Regulation;

(b) to fewer than 150 natural or legal persons (other than qualified investors as defined under Article 2 of the Prospectus Regulation), subject to obtaining the prior consent of the representatives for any such offer; or

(c) in any other circumstances falling within Article 1(4) of the Prospectus Regulation,

provided that no such offer of ADSs shall require us or any of the representatives to publish a prospectus pursuant to Article 3 of the Prospectus Regulation or supplement a prospectus pursuant to Article 23 of the Prospectus Regulation.

For the purposes of this provision, the expression an “offer to the public” in relation to the ADSs in any Relevant Member State means the communication in any form and by any means of sufficient information on the terms of the offer and any ADSs to be offered so as to enable an investor to decide to purchase any ADSs, and the expression “Prospectus Regulation” means Regulation (EU) 2017/1129.

Each person in a Relevant Member State who receives any communication in respect of, or who acquires any ADSs under, the offering contemplated hereby will be deemed to have represented, warranted and agreed to and with each of the Underwriters and their affiliates and us that:

(a) it is a qualified investor within the meaning of the Prospectus Regulation; and

(b) in the case of any ADSs acquired by it as a financial intermediary, as that term is used in Article 5 of the Prospectus Regulation, (i) the ADSs acquired by it in the offering have not been acquired on a non-discretionary basis on behalf of, nor have they been acquired with a view to their offer or resale to, persons in any Relevant Member State other than qualified investors, as that term is defined in the Prospectus Regulation, or have been

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acquired in other circumstances falling within the points (a) to (d) of Article 1(4) of the Prospectus Regulation and the prior consent of the representatives has been given to the offer or resale; or (ii) where the ADSs have been acquired by it on behalf of persons in any Relevant Member State other than qualified investors, the offer of those ADSs to it is not treated under the Prospectus Regulation as having been made to such persons.

We, the underwriters and their affiliates, and others will rely upon the truth and accuracy of the foregoing representation, acknowledgement and agreement. Notwithstanding the above, a person who is not a qualified investor and who has notified the representatives of such fact in writing may, with the prior consent of the representatives, be permitted to acquire ADSs in the offering.

United Kingdom

No ADSs have been offered or will be offered pursuant to the offering to the public in the United Kingdom prior to the publication of a prospectus in relation to the ADSs which has been approved by the Financial Conduct Authority, except that the ADSs may be offered to the public in the United Kingdom at any time:

(a) to any legal entity which is a qualified investor as defined under Article 2 of the UK Prospectus Regulation;

(b) to fewer than 150 natural or legal persons (other than qualified investors as defined under Article 2 of the UK Prospectus Regulation), subject to obtaining the prior consent of representatives for any such offer; or

(c) in any other circumstances falling within Section 86 of the Financial Services and Markets Act 2000 (“FSMA”),

provided that no such offer of the ADSs shall require us and/or any underwriters or any of their affiliates to publish a prospectus pursuant to Section 85 of the FSMA or supplement a prospectus pursuant to Article 23 of the UK Prospectus Regulation. For the purposes of this provision, the expression an “offer to the public” in relation to the ADSs in the United Kingdom means the communication in any form and by any means of sufficient information on the terms of the offer and any ADSs to be offered so as to enable an investor to decide to purchase or subscribe for any ADSs and the expression “UK Prospectus Regulation” means Regulation (EU) 2017/1129 as it forms part of domestic law in the UK by virtue of the European Union (Withdrawal) Act 2018.

In addition, in the United Kingdom, this prospectus supplement and any other material in relation to the ADSs described herein is being distributed only to, and is directed only at, and any offer subsequently made may only be directed at persons who are “qualified investors” (as defined in the UK Prospectus Regulation) (i) who have professional experience in matters relating to investments who fall within the definition of investment professionals in Article 19(5) of the FPO; or (ii) who are high net worth entities falling within Article 49(2)(a) to (d) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the “FPO”); (iii) who are outside the UK; or (iv) to whom an invitation or inducement to engage in investment activity (within the meaning of Section 21 of the FSMA) in connection with the issue or sale of any ADSs may otherwise lawfully be communicated or caused to be communicated, (all such persons together being referred to as “Relevant Persons”). The ADSs are only available in the UK to, and any invitation, offer or agreement to purchase or otherwise acquire the ADSs will be engaged in only with, the Relevant Persons. This prospectus supplement and its contents are confidential and should not be distributed, published or reproduced (in whole or in part) or disclosed by recipients to any other person in the UK. Any person in the UK that is not a Relevant Person should not act or rely on this prospectus supplement or any of its contents.

Each person in the UK who acquires any ADSs in the offering or to whom any offer is made will be deemed to have represented, acknowledged and agreed to and with us, the underwriters and their affiliates that it meets the criteria outlined in this section.

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Canada

The securities may be sold in Canada only to purchasers purchasing, or deemed to be purchasing, as principal that are accredited investors, as defined in National Instrument 45-106 Prospectus Exemptions or subsection 73.3(1) of the Securities Act (Ontario), and are permitted clients, as defined in National Instrument 31-103 Registration Requirements, Exemptions, and Ongoing Registrant Obligations. Any resale of the securities must be made in accordance with an exemption form, or in a transaction not subject to, the prospectus requirements of applicable securities laws.

Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if this prospectus supplement (including any amendment thereto) contains a misrepresentation, provided that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation of the purchaser’s province or territory. The purchaser should refer to any applicable provisions of the securities legislation of the purchaser’s province or territory of these rights or consult with a legal advisor.

Pursuant to section 3A.3 of National Instrument 33-105 Underwriting Conflicts (NI 33-105), the underwriters are not required to comply with the disclosure requirements of NI 33-105 regarding underwriter conflicts of interest in connection with this offering.

Hong Kong

The ADSs may not be offered or sold in Hong Kong by means of any document other than (i) in circumstances which do not constitute an offer to the public within the meaning of the Companies (Winding Up and Miscellaneous Provisions) Ordinance (Cap. 32 of the Laws of Hong Kong) (“Companies (Winding Up and Miscellaneous Provisions) Ordinance”) or which do not constitute an invitation to the public within the meaning of the Securities and Futures Ordinance (Cap. 571 of the Laws of Hong Kong) (“Securities and Futures Ordinance”), or (ii) to “professional investors” as defined in the Securities and Futures Ordinance and any rules made thereunder, or (iii) in other circumstances which do not result in the document being a “prospectus” as defined in the Companies (Winding Up and Miscellaneous Provisions) Ordinance, and no advertisement, invitation or document relating to the ADSs may be issued or may be in the possession of any person for the purpose of issue (in each case whether in Hong Kong or elsewhere), which is directed at, or the contents of which are likely to be accessed or read by, the public in Hong Kong (except if permitted to do so under the securities laws of Hong Kong) other than with respect to ADSs which are or are intended to be disposed of only to persons outside Hong Kong or only to “professional investors” in Hong Kong as defined in the Securities and Futures Ordinance and any rules made thereunder.

Singapore

This prospectus supplement has not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, this prospectus supplement and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of the ADSs may not be circulated or distributed, nor may the ADSs be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to persons in Singapore other than (i) to an institutional investor (as defined under Section 4A of the Securities and Futures Act, Chapter 289 of Singapore (the “SFA”)) under Section 274 of the SFA, (ii) to a relevant person (as defined in Section 275(2) of the SFA) pursuant to Section 275(1) of the SFA, or any person pursuant to Section 275(1A) of the SFA, and in accordance with the conditions specified in Section 275 of the SFA or (iii) otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA, in each case subject to conditions set forth in the SFA.

Where the ADSs are subscribed or purchased under Section 275 of the SFA by a relevant person which is a corporation (which is not an accredited investor (as defined in Section 4A of the SFA)) the sole business of

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which is to hold investments and the entire share capital of which is owned by one or more individuals, each of whom is an accredited investor, the securities (as defined in Section 239(1) of the SFA) of that corporation shall not be transferable for 6 months after that corporation has acquired the ADSs under Section 275 of the SFA except: (1) to an institutional investor under Section 274 of the SFA or to a relevant person (as defined in Section 275(2) of the SFA), (2) where such transfer arises from an offer in that corporation’s securities pursuant to Section 275(1A) of the SFA, (3) where no consideration is or will be given for the transfer, (4) where the transfer is by operation of law, (5) as specified in Section 276(7) of the SFA, or (6) as specified in Regulation 32 of the Securities and Futures (Offers of Investments) (Shares and Debentures) Regulations 2005 of Singapore (“Regulation 32”)

Where the ADSs are subscribed or purchased under Section 275 of the SFA by a relevant person which is a trust (where the trustee is not an accredited investor (as defined in Section 4A of the SFA)) whose sole purpose is to hold investments and each beneficiary of the trust is an accredited investor, the beneficiaries’ rights and interest (howsoever described) in that trust shall not be transferable for 6 months after that trust has acquired the ADSs under Section 275 of the SFA except: (1) to an institutional investor under Section 274 of the SFA or to a relevant person (as defined in Section 275(2) of the SFA), (2) where such transfer arises from an offer that is made on terms that such rights or interest are acquired at a consideration of not less than S$200,000 (or its equivalent in a foreign currency) for each transaction (whether such amount is to be paid for in cash or by exchange of securities or other assets), (3) where no consideration is or will be given for the transfer, (4) where the transfer is by operation of law, (5) as specified in Section 276(7) of the SFA, or (6) as specified in Regulation 32.

Japan

The securities have not been and will not be registered under the Financial Instruments and Exchange Act of Japan (Act No. 25 of 1948, as amended), or the FIEA. The securities may not be offered or sold, directly or indirectly, in Japan or to or for the benefit of any resident of Japan (including any person resident in Japan or any corporation or other entity organized under the laws of Japan) or to others for reoffering or resale, directly or indirectly, in Japan or to or for the benefit of any resident of Japan, except pursuant to an exemption from the registration requirements of the FIEA and otherwise in compliance with any relevant laws and regulations of Japan.

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CERTAIN MATERIAL INCOME TAX CONSIDERATIONS

The following summary contains a description of certain material U.K. and U.S. federal income tax consequences of the acquisition, ownership and disposition of our ordinary shares or ADSs. This summary should not be considered a comprehensive description of all the tax considerations that may be relevant to the decision to acquire ordinary shares or ADSs in this offering.

Certain Material United States Federal Income Tax Considerations for U.S. Holders

The following is a description of certain material U.S. federal income tax consequences to the U.S. Holders described below of owning and disposing of ADSs. It is not a comprehensive description of all tax considerations that may be relevant to a particular person’s decision to acquire securities. This discussion applies only to a U.S. Holder that is an initial purchaser of ADSs pursuant to the offering and that holds our ADSs as a capital asset for tax purposes (generally, property held for investment). In addition, it does not describe all of the tax consequences that may be relevant in light of a U.S. Holder’s particular circumstances, including state and local tax consequences, estate tax consequences, alternative minimum tax consequences, the potential application of the Medicare contribution tax, and tax consequences applicable to U.S. Holders subject to special rules, such as:

• banks, insurance companies, and certain other financial institutions;

• U.S. expatriates and certain former citizens or long-term residents of the United States;

• dealers or traders in securities who use a mark-to-market method of tax accounting;

• persons holding ADSs as part of a hedging transaction, “straddle,” wash sale, conversion transaction or integrated transaction or persons entering into a constructive sale with respect to ADSs;

• persons whose “functional currency” for U.S. federal income tax purposes is not the U.S. dollar;

• brokers, dealers or traders in securities, commodities or currencies;

• tax-exempt entities or government organizations;

• S corporations, partnerships, or other entities or arrangements classified as partnerships for U.S. federal income tax purposes;

• persons who are subject to special tax accounting under Section 451(b) of the Code (as defined below);

• regulated investment companies or real estate investment trusts;

• persons who acquired our ADSs pursuant to the exercise of any employee share option or otherwise as compensation;

• persons holding our ADSs in connection with a trade or business, permanent establishment, or fixed base outside the United States; and

• persons who own (directly or through attribution) 10% or more (by vote or value) of our outstanding ordinary shares or ADSs.

If an entity that is classified as a partnership for U.S. federal income tax purposes holds ADSs, the U.S. federal income tax treatment of a partner will generally depend on the status of the partner and the activities of the partnership. Partnerships holding ADSs and partners in such partnerships are encouraged to consult their tax advisors as to the particular U.S. federal income tax consequences of holding and disposing of ADSs.

The discussion is based on the Internal Revenue Code of 1986, as amended (the “Code”), administrative pronouncements, judicial decisions, final, temporary and proposed Treasury Regulations, and the income tax treaty between the United Kingdom and the United States, all as of the date hereof, changes to any of which may affect the tax consequences described herein—possibly with retroactive effect.

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A “U.S. Holder” is a holder who, for U.S. federal income tax purposes, is a beneficial owner of ADSs and is:

(i) an individual who is a citizen or individual resident of the United States;

(ii) a corporation, or other entity taxable as a corporation, created or organized in or under the laws of the United States, any state therein or the District of Columbia;

(iii) an estate the income of which is subject to U.S. federal income taxation regardless of its source; or

(iv) a trust if (1) a U.S. court is able to exercise primary supervision over the administration of the trust and one or more U.S. persons have authority to control all substantial decisions of the trust or (2) the trust has a valid election in effect to be treated as a U.S. person under applicable U.S. Treasury Regulations.

The discussion below assumes that the representations contained in the deposit agreement are true and that the obligations in the deposit agreement and any related agreement will be complied with in accordance with their terms. Generally, a U.S. Holder of an ADS should be treated for U.S. federal income tax purposes as holding the ordinary shares represented by our ADS. Accordingly, no gain or loss will be recognized upon an exchange of ADSs for ordinary shares. The U.S. Treasury has expressed concerns that intermediaries in the chain of ownership between the holder of an ADS and the issuer of the security underlying the ADS may be taking actions that are inconsistent with the beneficial ownership of the underlying security. Accordingly, the creditability of foreign taxes, if any, as described below, could be affected by actions taken by intermediaries in the chain of ownership between the holders of ADSs and our company if as a result of such actions the holders of ADSs are not properly treated as beneficial owners of the underlying ordinary shares. These actions would also be inconsistent with the claiming of the reduced tax rate, described below, applicable to dividends received by certain non-corporate holders.

PERSONS CONSIDERING AN INVESTMENT IN ADSs SHOULD CONSULT THEIR TAX ADVISORS AS TO THE PARTICULAR TAX CONSEQUENCES APPLICABLE TO THEM RELATING TO THE ACQUISITION, OWNERSHIP AND DISPOSITION OF THE ORDINARY SHARES OR ADSs, INCLUDING THE APPLICABILITY OF U.S. FEDERAL, STATE AND LOCAL TAX LAWS.

PFIC Rules

If we are classified as a passive foreign investment company (“PFIC”) in any taxable year, a U.S. Holder will be subject to special rules generally intended to reduce or eliminate any benefits from the deferral of U.S. federal income tax that a U.S. Holder could derive from investing in a non-U.S. company that does not distribute all of its earnings on a current basis.

A non-U.S. corporation will be classified as a PFIC for any taxable year in which, after applying certain look-through rules, either:

• at least 75% of its gross income is passive income (such as interest income); or

• at least 50% of its gross assets (determined on the basis of a quarterly weighted average under applicable Treasury Regulations) is attributable to assets that produce passive income or are held for the production of passive income.

We will be treated as owning our proportionate share of the assets and earning our proportionate share of the income of any other corporation, the equity of which we own, directly or indirectly, 25% or more (by value).

While we do not believe we were a PFIC for 2023 and we do not expect we will be a PFIC for the current tax year, it is uncertain whether we or any of our subsidiaries will be treated as a PFIC for U.S. federal income tax purposes for past, current or any subsequent tax year. The determination of whether we are a PFIC is a fact-intensive determination made on an annual basis applying principles and methodologies that in some circumstances are unclear and subject to varying interpretation. No assurances can be given that a tax authority

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would agree with any conclusions we make regarding our PFIC status. Under the income test described above, our status as a PFIC depends on the composition of our income which will depend on the transactions we enter into in the future and our corporate structure. The composition of our income, and assets is also affected by the spending of the cash we raise in any offering, including this offering. Because PFIC status is based on our income, assets, and activities for the entire taxable year, we cannot make a final determination at this time as to whether we will be a PFIC for 2024 and our PFIC status may change from year to year. Although we will try to manage our business to avoid becoming a PFIC, our operations currently generate very limited amounts of non-passive income. Until we generate sufficient revenue from active licensing and other non-passive sources, there is a risk that we will be a PFIC under the PFIC income test.

If we are classified as a PFIC in any year with respect to which a U.S. Holder owns the ordinary shares or ADSs, we will continue to be treated as a PFIC with respect to such U.S. Holder in all succeeding years during which the U.S. Holder owns the ordinary shares or ADSs, regardless of whether we continue to meet the tests described above unless (i) we cease to be a PFIC and the U.S. Holder has made a “deemed sale” election under the PFIC rules, or (ii) the U.S. Holder elects to treat us as a “qualified electing fund” under Section 1295 of the Code (such an election, a “QEF Election”), as discussed below, with respect to all taxable years during such U.S. Holder’s holding period in which we are a PFIC. If the “deemed sale” election is made, a U.S. Holder will be deemed to have sold the ordinary shares or ADSs the U.S. Holder holds at their fair market value and any gain from such deemed sale would be subject to the rules described below. After the deemed sale election, so long as we do not become a PFIC in a subsequent taxable year, the U.S. Holder’s ordinary shares or ADSs with respect to which such election was made will not be treated as shares in a PFIC and the U.S. Holder will not be subject to the rules described below with respect to any “excess distribution” the U.S. Holder receives from us or any gain from an actual sale or other disposition of the ordinary shares or ADSs. U.S. Holders should consult their tax advisors as to the possibility and consequences of making a deemed sale election if we cease to be a PFIC and such election becomes available.

For each taxable year we are treated as a PFIC with respect to U.S. Holders, U.S. Holders will be subject to special tax rules with respect to any “excess distribution” such U.S. Holder receives and any gain such U.S. Holder recognizes from a sale or other disposition (including, under certain circumstances, a pledge) of ordinary shares or ADSs, unless (i) such U.S. Holder makes a QEF Election as discussed below or (ii) our ordinary shares or ADSs constitute “marketable” securities, and such U.S. Holder makes a mark-to-market election as discussed below. Distributions a U.S. Holder receives in a taxable year that are greater than 125% of the average annual distributions a U.S. Holder received during the shorter of the three preceding taxable years or the U.S. Holder’s holding period for the ordinary shares or ADSs will be treated as an excess distribution. Under these special tax rules:

• the excess distribution or gain will be allocated ratably over a U.S. Holder’s holding period for the ordinary shares or ADSs;

• the amount allocated to the current taxable year, and any taxable year prior to the first taxable year in which we became a PFIC, will be treated as ordinary income; and

• the amount allocated to each other year will be subject to the highest tax rate in effect for that year and the interest charge generally applicable to underpayments of tax will be imposed on the resulting tax attributable to each such year.

The tax liability for amounts allocated to years prior to the year of disposition or “excess distribution” cannot be offset by any net operating losses for such years, and gains (but not losses) realized on the sale of the ordinary shares or ADSs cannot be treated as capital, even if a U.S. Holder holds the ordinary shares or ADSs as capital assets.

If a U.S. Holder makes a QEF Election with respect to a PFIC, it will be taxed currently on its pro rata share of the PFIC’s ordinary earnings and net capital gain (at ordinary income and capital gain rates, respectively) for

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each taxable year that the entity is a PFIC, even if no distributions were received. Any distributions we make out of our earnings and profits that were previously included in such a U.S. Holder’s income under the QEF Election would not be taxable to such U.S. Holder. Such U.S. Holder’s tax basis in its ordinary shares or ADSs would be increased by an amount equal to any income included under the QEF Election and decreased by any amount distributed on the ordinary shares or ADSs that is not included in its income. In addition, a U.S. Holder will recognize capital gain or loss on the disposition of its ordinary shares or ADSs in an amount equal to the difference between the amount realized and its adjusted tax basis in the ordinary shares or ADSs, each as determined in U.S. dollars. Once made, a QEF Election remains in effect unless invalidated or terminated by the Internal Revenue Service (the “IRS”) or revoked by the shareholder. A QEF Election can be revoked only with the consent of the IRS. A U.S. Holder will not be currently taxed on the ordinary income and net capital gain of a PFIC with respect to which a QEF Election was made for any taxable year of the non-U.S. corporation that such corporation does not satisfy the PFIC income test or asset test, as described above. If we determine that we are a PFIC for this year or any future taxable year, we currently expect that we would provide the information necessary for U.S. Holders to make a QEF Election. However, there is also no assurance that we will have timely knowledge of our status as a PFIC in the future or of the required information to be provided.

U.S. Holders can avoid the interest charge on excess distributions or gain relating to the ordinary shares or ADSs by making a mark-to-market election with respect to the ordinary shares or ADSs, provided that the ordinary shares or ADSs are “marketable.” Ordinary shares or ADSs will be marketable if they are “regularly traded” on certain U.S. stock exchanges or on a foreign stock exchange that meets certain conditions. For these purposes, the ordinary shares or ADSs will be considered regularly traded during any calendar year during which they are traded, other than in de minimis quantities, on at least 15 days during each calendar quarter. Any trades that have as their principal purpose meeting this requirement will be disregarded. Our ADSs are listed on Nasdaq, which is a qualified exchange for these purposes. Consequently, if our ADSs remain listed on Nasdaq and are regularly traded, and you are a holder of ADSs, we expect the mark-to-market election would be available to U.S. Holders if we are a PFIC. Each U.S. Holder should consult its tax advisor as to the whether a mark-to-market election is available or advisable with respect to the ordinary shares or ADSs.

A U.S. Holder that makes a mark-to-market election must include in ordinary income for each year an amount equal to the excess, if any, of the fair market value of the ordinary shares or ADSs at the close of the taxable year over the U.S. Holder’s adjusted tax basis in the ordinary shares or ADSs. An electing U.S. Holder may also claim an ordinary loss deduction for the excess, if any, of the U.S. Holder’s adjusted basis in the ordinary shares or ADSs over the fair market value of the ordinary shares or ADSs at the close of the taxable year, but this deduction is allowable only to the extent of any net mark-to-market gains for prior years. Gains from an actual sale or other disposition of the ordinary shares or ADSs will be treated as ordinary income, and any losses incurred on a sale or other disposition of the shares will be treated as an ordinary loss to the extent of any net mark-to-market gains for prior years. Once made, the election cannot be revoked without the consent of the IRS unless the ordinary shares or ADSs cease to be marketable. However, a mark-to-market election generally cannot be made for equity interests in any lower-tier PFICs that we own, unless shares of such lower-tier PFIC are themselves “marketable.” As a result, even if a U.S. Holder validly makes a mark-to-market election with respect to our ordinary shares or ADSs, the U.S. Holder may continue to be subject to the PFIC rules (described above) with respect to its indirect interest in any of our investments that are treated as an equity interest in a PFIC for U.S. federal income tax purposes. U.S. Holders should consult their tax advisors to determine whether any of the elections described above would be available and if so, what the consequences of the alternative treatments would be in their particular circumstances.

While we do not believe we were a PFIC in 2023 and we do not expect we will be a PFIC for the current tax year, if we are a PFIC in the current or any subsequent year and, at any time when we are a PFIC, have a foreign subsidiary that is classified as a PFIC, U.S. Holders generally would be deemed to own a portion of the shares of such lower-tier PFIC, and generally could incur liability for the deferred tax and interest charge described above if we receive a distribution from, or dispose of all or part of our interest in, the lower-tier PFIC or the U.S. Holders otherwise were deemed to have disposed of an interest in the lower-tier PFIC. If we determine that we

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are a PFIC, we will provide the information necessary for U.S. Holders to make or maintain a QEF election with respect to us and we will cause any lower-tier PFIC that we control to provide to a U.S. Holder the information necessary for U.S. Holders to make or maintain a QEF election with respect to such lower-tier PFIC. However, in the future, we may not hold a controlling interest in any such lower-tier PFIC and thus there can be no assurance that we will be able to cause the lower-tier PFIC to provide such required information. A mark-to-market election generally would not be available with respect to such lower-tier PFIC. U.S. Holders are urged to consult their tax advisors regarding the tax issues raised by lower-tier PFICs.

Unless otherwise provided by the U.S. Treasury, each U.S. shareholder of a PFIC is required to file an annual report containing such information as the U.S. Treasury may require. A U.S. Holder’s failure to file the annual report will cause the statute of limitations for such U.S. Holder’s U.S. federal income tax return to remain open with regard to the items required to be included in such report until three years after the U.S. Holder files the annual report, and, unless such failure is due to reasonable cause and not willful neglect, the statute of limitations for the U.S. Holder’s entire U.S. federal income tax return will remain open during such period. U.S. Holders should consult their tax advisors regarding the requirements of filing such information returns under these rules.

WE STRONGLY URGE YOU TO CONSULT YOUR TAX ADVISOR REGARDING THE IMPACT OF OUR PFIC STATUS ON YOUR INVESTMENT IN THE ORDINARY SHARES OR ADSs AS WELL AS THE APPLICATION OF THE PFIC RULES TO YOUR INVESTMENT IN THE ORDINARY SHARES OR ADSs.

Taxation of Distributions

Subject to the discussion above under “PFIC Rules”, distributions paid on ordinary shares or ADSs, other than certain pro rata distributions of ordinary shares or ADSs, will generally be treated as dividends to the extent paid out of our current or accumulated earnings and profits (as determined under U.S. federal income tax principles). Because we may not calculate our earnings and profits under U.S. federal income tax principles, we expect that distributions generally will be reported to U.S. Holders as dividends. Subject to applicable limitations and the discussions above regarding concerns expressed by the U.S. Treasury, dividends paid to certain non-corporate U.S. Holders may be taxable at preferential rates applicable to “qualified dividend income” if we are a “qualified foreign corporation” and certain other requirements are met. However, the qualified dividend income treatment may not apply if we are treated as a PFIC with respect to the U.S. Holder. The amount of the dividend will be treated as foreign-source dividend income to U.S. Holders and will not be eligible for the dividends-received deduction generally available to U.S. corporations under the Code. Dividends will generally be included in a U.S. Holder’s income on the date of the U.S. Holder’s receipt of the dividend. The amount of any dividend income paid in foreign currency will be the U.S. dollar amount calculated by reference to the exchange rate in effect on the date of actual or constructive receipt, regardless of whether the payment is in fact converted into U.S. dollars. If the dividend is converted into U.S. dollars on the date of receipt, a U.S. Holder should not be required to recognize foreign currency gain or loss in respect of the dividend income. A U.S. Holder may have foreign currency gain or loss if the dividend is converted into U.S. dollars after the date of receipt. Such gain or loss would generally be treated as U.S.-source ordinary income or loss. The amount of any distribution of property other than cash (and other than certain pro rata distributions of ordinary shares or ADSs or rights to acquire ordinary shares or ADSs) will be the fair market value of such property on the date of distribution. For foreign tax credit limitation purposes, our dividends will generally be treated as passive category income. Because under current law no U.K. income taxes will be withheld from dividends on ordinary shares or ADSs, there will be no creditable foreign taxes associated with any dividends that a U.S. Holder will receive. The rules governing foreign tax credits are complex and U.S. Holders should therefore consult their tax advisors regarding the effect of the receipt of dividends for foreign tax credit limitation purposes.

Sale or Other Taxable Disposition of Ordinary Shares and ADSs

Subject to the discussion above under “PFIC Rules”, gain or loss realized on the sale or other taxable disposition of ordinary shares or ADSs will be capital gain or loss, and will be long-term capital gain or loss if the U.S.

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Holder held the ordinary shares or ADSs for more than one year at the time of sale or other taxable disposition. The amount of the gain or loss will equal the difference between the U.S. Holder’s tax basis in the ordinary shares or ADSs disposed of and the amount realized on the disposition, in each case as determined in U.S. dollars. This gain or loss will generally be U.S.-source gain or loss for foreign tax credit purposes. Subject to the PFIC rules described above, long-term capital gains recognized by certain non-corporate U.S. Holders (including individuals) will generally be subject to reduced rates of U.S. federal income tax. The deductibility of capital losses is subject to limitations.

If the consideration received by a U.S. Holder is not paid in U.S. dollars, the amount realized will be the U.S. dollar value of the payment received determined by reference to the spot rate of exchange on the date of the sale or other disposition. However, if the ordinary shares or ADSs are treated as traded on an “established securities market” and the U.S. Holder is either a cash basis taxpayer or an accrual basis taxpayer that has made a special election (which must be applied consistently from year to year and cannot be changed without the consent of the IRS), such U.S. Holder will determine the U.S. dollar value of the amount realized in a non-U.S. dollar currency by translating the amount received at the spot rate of exchange on the settlement date of the sale. If a U.S. Holder is an accrual basis taxpayer that is not eligible to or does not elect to determine the amount realized using the spot rate on the settlement date, such U.S. Holder will recognize foreign currency gain or loss to the extent of any difference between the U.S. dollar amount realized on the date of sale or disposition and the U.S. dollar value of the currency received at the spot rate on the settlement date.

Information Reporting and Backup Withholding

Payments of dividends and sales proceeds that are made within the United States or through certain U.S.-related financial intermediaries generally are subject to information reporting, and may be subject to backup withholding, unless (i) the U.S. Holder is a corporation or other exempt recipient or (ii) in the case of backup withholding, the U.S. Holder provides a correct taxpayer identification number and certifies that it is not subject to backup withholding on a duly executed IRS Form W-9 or otherwise establishes an exemption.

Backup withholding is not an additional tax. The amount of any backup withholding from a payment to a U.S. Holder may be allowed as a credit against the U.S. Holder’s U.S. federal income tax liability and may entitle the U.S. Holder to a refund, provided that the required information is timely furnished to the IRS.

Information with Respect to Foreign Financial Assets

Certain U.S. Holders who are individuals (and, under regulations, certain entities) may be required to report information relating to the ordinary shares or ADSs, subject to certain exceptions (including an exception for ordinary shares or ADSs held in accounts maintained by certain U.S. financial institutions), by filing IRS Form 8938 (Statement of Specified Foreign Financial Assets) with their federal income tax return. Such U.S. Holders who fail to timely furnish the required information may be subject to a penalty. Additionally, if a U.S. Holder does not file the required information, the statute of limitations with respect to tax returns of the U.S. Holder to which the information relates may not close until three years after such information is filed. U.S. Holders should consult their tax advisors regarding their reporting obligations with respect to their ownership and disposition of the ordinary shares or ADSs.

U.K. Taxation

The following is intended as a general guide to current U.K. tax law and HM Revenue & Customs, or HMRC, practice applying as at the date of this prospectus supplement (both of which are subject to change at any time, possibly with retrospective effect) relating to the holding of ADSs. It does not constitute legal or tax advice and does not purport to be a complete analysis of all U.K. tax considerations relating to the holding of ADSs, or all of the circumstances in which holders of ADSs may benefit from an exemption or relief from U.K. taxation. It is written on the basis that the company does not (and will not) directly or indirectly derive 75% or more of its

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qualifying asset value from U.K. land, and that the company is and remains solely resident in the United Kingdom for tax purposes and will therefore be subject to the U.K. tax regime and not the U.S. tax regime save as set out above under “Certain Material United States Federal Income Tax Considerations for U.S. Holders.”

Except to the extent that the position of non-U.K. resident persons is expressly referred to, this guide relates only to persons who are resident (and, in the case of individuals, domiciled or deemed domiciled and to whom split year treatment does not apply) for tax purposes solely in the United Kingdom and do not have a permanent establishment, branch, agency (or equivalent) or fixed base in any other jurisdiction with which the holding of the ADSs is connected, or U.K. Holders, who are absolute beneficial owners of the ADSs (where the ADSs are not held through an Individual Savings Account or a Self-Invested Personal Pension) and who hold the ADSs as investments.

This guide may not relate to certain classes of U.K. Holders, such as (but not limited to):

• persons who are connected with the company;

• financial institutions;

• insurance companies;

• charities or tax-exempt organizations;

• collective investment schemes;

• pension schemes;

• market makers, intermediaries, brokers or dealers in securities;

• persons who have (or are deemed to have) acquired their ADSs by virtue of an office or employment or who are or have been officers or employees of the company or any of its affiliates; and

• individuals who are subject to U.K. taxation on a remittance basis.

The decision of the First-tier Tribunal (Tax Chamber) in HSBC Holdings PLC and The Bank of New York Mellon Corporation v HMRC (2012) cast some doubt on whether a holder of a depositary receipt is the beneficial owner of the underlying shares. However, based on published HMRC guidance we would expect that HMRC will regard a holder of ADSs as holding the beneficial interest in the underlying shares and therefore these paragraphs assume that a holder of ADSs is the beneficial owner of the underlying ordinary shares and any dividends paid in respect of the underlying ordinary shares (where the dividends are regarded for U.K. purposes as that person’s own income) for U.K. direct tax purposes.

THESE PARAGRAPHS ARE A SUMMARY OF CERTAIN U.K. TAX CONSIDERATIONS AND ARE INTENDED AS A GENERAL GUIDE ONLY. IT IS RECOMMENDED THAT ALL HOLDERS OF ADSs OBTAIN ADVICE AS TO THE CONSEQUENCES OF THE ACQUISITION, OWNERSHIP AND DISPOSAL OF THE ADSs IN THEIR OWN SPECIFIC CIRCUMSTANCES FROM THEIR OWN TAX ADVISORS. IN PARTICULAR, NON-U.K. RESIDENT OR DOMICILED PERSONS ARE ADVISED TO CONSIDER THE POTENTIAL IMPACT OF ANY RELEVANT DOUBLE TAXATION AGREEMENTS.

Dividends

Withholding Tax

Dividends paid by the company will not be subject to any withholding or deduction for or on account of U.K. tax.

Income Tax

An individual U.K. Holder may, depending on his or her particular circumstances, be subject to U.K. tax on dividends received from the company. An individual holder of ADSs who is not resident for tax purposes in the

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United Kingdom should not be chargeable to U.K. income tax on dividends received from the company unless he or she carries on (whether solely or in partnership) a trade, profession or vocation in the United Kingdom through a branch or agency to which the ADSs are attributable. There are certain exceptions for trading in the United Kingdom through independent agents, such as some brokers and investment managers.

All dividends received by an individual U.K. Holder from us or from other sources will form part of that U.K. Holder’s total income for income tax purposes and will constitute the top slice of that income. A nil rate of income tax will apply to the first £500 of taxable dividend income received by the individual U.K. Holder in the tax year 2024/2025. Income within the nil rate band will be taken into account in determining whether income in excess of the £500 tax-free allowance falls within the basic rate, higher rate or additional rate tax bands. Dividend income in excess of the tax-free allowance will (subject to the availability of any income tax personal allowance) be taxed at 8.75% to the extent that the excess amount falls within the basic rate tax band, 33.75% to the extent that the excess amount falls within the higher rate tax band and 39.35% to the extent that the excess amount falls within the additional rate tax band.

Corporation Tax

A corporate holder of ADSs who is not resident for tax purposes in the United Kingdom should not be chargeable to U.K. corporation tax on dividends received from the company unless it carries on (whether solely or in partnership) a trade in the United Kingdom through a permanent establishment to which the ADSs are attributable.

Corporate U.K. Holders should not be subject to U.K. corporation tax on any dividend received from the company so long as the dividends qualify for exemption, which should be the case, although certain conditions must be met. If the conditions for the exemption are not satisfied, or such U.K. Holder elects for an otherwise exempt dividend to be taxable, U.K. corporation tax will be chargeable on the amount of any dividends (at the main rate of 25% for companies with profits in excess of £250,000, or the small profits rate of 19% for companies with profits of £50,000 or less, with marginal relief from the main rate available to companies with profits between £50,000 and £250,000, subject to meeting certain criteria).

Chargeable Gains

A disposal or deemed disposal of ADSs by a U.K. Holder may, depending on the U.K. Holder’s circumstances and subject to any available exemptions or reliefs (such as the annual exemption), give rise to a chargeable gain or an allowable loss for the purposes of U.K. capital gains tax and corporation tax on chargeable gains.

If an individual U.K. Holder who is subject to U.K. income tax at either the higher or the additional rate is liable to U.K. capital gains tax on the disposal of ADSs, the current applicable rate will be 20%. For an individual U.K. Holder who is subject to U.K. income tax at the basic rate and liable to U.K. capital gains tax on such disposal, the current applicable rate would be 10%, save to the extent that any capital gains when aggregated with the U.K. Holder’s other taxable income and gains in the relevant tax year exceed the unused basic rate tax band. In that case, the rate currently applicable to the excess would be 20%.

If a corporate U.K. Holder becomes liable to U.K. corporation tax on the disposal (or deemed disposal) of ADSs, U.K. corporation tax would apply (at the main rate of 25% for companies with profits in excess of £250,000, or the small profits rate of 19% for companies with profits of £50,000 or less, with marginal relief from the main rate available to companies with profits between £50,000 and £250,000, subject to meeting certain criteria).

A holder of ADSs which is not resident for tax purposes in the United Kingdom should not normally be liable to U.K. capital gains tax or corporation tax on chargeable gains on a disposal (or deemed disposal) of ADSs, unless the person is carrying on (whether solely or in partnership) a trade, profession or vocation in the United Kingdom through a branch or agency (or, in the case of a corporate holder of ADSs, through a permanent establishment) to

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which the ADSs are attributable. However, an individual holder of ADSs who has ceased to be resident for tax purposes in the United Kingdom for a period of less than five years and who disposes of ADSs during that period may be liable on his or her return to the United Kingdom to U.K. tax on any capital gain realized (subject to any available exemption or relief).

Stamp Duty and Stamp Duty Reserve Tax

The discussion below relates to the holders of our ordinary shares or ADSs wherever resident, however it should be noted that special rules may apply to certain persons such as market makers, brokers, dealers or intermediaries.

Issue of Ordinary Shares

No U.K. stamp duty or stamp duty reserve tax (“SDRT”) is payable on the issue of the underlying ordinary shares in the company.

Transfers of Ordinary Shares

An unconditional agreement to transfer ordinary shares in certificated form will normally give rise to a charge to SDRT at the rate of 0.5% of the amount or value of the consideration payable for the transfer. The purchaser of the ordinary shares is liable for the SDRT. Transfers of ordinary shares in certificated form are generally also subject to stamp duty at the rate of 0.5% of the amount or value of the consideration given for the transfer (rounded up to the next £5.00). Stamp duty is normally paid by the purchaser. The charge to SDRT will be canceled or, if already paid, repaid (generally with interest), where a transfer instrument has been duly stamped within six years of the charge arising (either by paying the stamp duty or by claiming an appropriate relief) or if the instrument is otherwise exempt from stamp duty.

In principle, when ordinary shares are transferred into a depositary receipt system or a clearance service (including to a nominee, or agent for, a person whose business is or includes the issue of depositary receipts or the provision of clearance services), a higher rate of 1.5% UK stamp duty or UK SDRT (the “1.5% Charge”), as applicable, generally arises. However, with effect from 1 January 2024, no 1.5% Charge arises in respect of an issue or a transfer of ordinary shares, or an unconditional agreement to transfer ordinary shares, to a clearance service or depositary receipt system that falls within the scope of a statutory exemption, including where the transfer is carried out in the course of “capital-raising arrangements”, being arrangements pursuant to which securities are issued for the purpose of raising new capital. Where any ordinary shares are subject to restrictions that have the effect of preventing the transfer of such ordinary shares into a clearance service or depositary receipt system in the course of capital-raising arrangements, such ordinary shares must be transferred as soon as reasonably practicable after the time at which the restriction ceases to have effect in order to prevent the 1.5% Charge from applying.

Where a clearance service has made and maintained an election under section 97A of the UK Finance Act 1986, no 1.5% Charge will apply on any transfer of ordinary shares, or an unconditional agreement to transfer ordinary shares, to that clearance service. It is understood that HMRC regards the facilities of DTC as a clearance service for these purposes, and we are not aware of any election under section 97A having been made by DTC.

If arising, any UK stamp duty or UK SDRT payable on a transfer of ordinary shares to a depositary receipt system or clearance service will in practice generally be paid by the transferors or participants in the clearance service or depositary receipt system.

Issue of ADSs

No U.K. stamp duty or SDRT is payable on the issue of ADSs in the company.

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Transfers of ADSs

No SDRT should be required to be paid on a paperless transfer of ADSs through the clearance service facilities of DTC, provided that no section 97A election has been made by DTC, and such ADSs are held through DTC at the time of any agreement for their transfer.

No U.K. stamp duty will in practice be payable on a written instrument transferring an ADS provided that the instrument of transfer is executed and remains at all times outside the United Kingdom. Where these conditions are not met, the transfer of, or agreement to transfer, an ADS could, depending on the circumstances, attract a charge to U.K. stamp duty at the rate of 0.5% of the amount or value of the consideration. If it is necessary to pay stamp duty, it may also be necessary to pay interest and penalties.

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LEGAL MATTERS

The validity of the ordinary shares to be represented by the ADSs offered hereby and certain matters of English law will be passed upon for us by Goodwin Procter (UK) LLP, and certain other matters of U.S. federal law will be passed upon for us by Goodwin Procter, Boston, Massachusetts. Cooley LLP, New York, New York and Cooley (UK) LLP, London, United Kingdom are representing the underwriters in this offering.

EXPERTS

The consolidated financial statements of Centessa Pharmaceuticals plc and subsidiaries as of December 31, 2023 and 2022, and for the years then ended, have been incorporated by reference herein and in the registration statement in reliance upon the report of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing.

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WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public at the SEC’s website at www.sec.gov. Copies of certain information filed by us with the SEC are also available on our website at http://www.centessa.com. Our website is not a part of this prospectus supplement and is not incorporated by reference in this prospectus supplement.

This prospectus supplement and the accompanying prospectus are part of the Registration Statement we filed with the SEC. This prospectus supplement and the accompanying prospectus omit some information contained in the Registration Statement in accordance with SEC rules and regulations. You should review the information and exhibits in the Registration Statement for further information about us and our consolidated subsidiaries and the securities we are offering. Statements in this prospectus supplement and the accompanying prospectus concerning any document we filed as an exhibit to the Registration Statement or that we otherwise filed with the SEC are not intended to be comprehensive and are qualified by reference to these filings. You should review the complete document to evaluate these statements. You can obtain a copy of the Registration Statement from the SEC’s website.

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INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to incorporate by reference much of the information we file with the SEC, which means that we can disclose important information to you by referring you to those publicly available documents. The information that we incorporate by reference in this prospectus supplement is considered to be part of this prospectus supplement. Because we are incorporating by reference future filings with the SEC, this prospectus supplement is continually updated and those future filings may modify or supersede some of the information included or incorporated in this prospectus supplement. This means that you must look at all of the SEC filings that we incorporate by reference to determine if any of the statements in this prospectus supplement or in any document previously incorporated by reference have been modified or superseded:

• Our Annual Report on Form 10-K for the year ended December 31, 2023, filed with the SEC on March 28, 2024;

• Our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2024 and June 30, 2024, filed with the SEC on May  13, 2024 and August 13, 2024, respectively;

• Our Current Reports on Form 8-K filed with the SEC on April 22, 2024, April  24, 2024, June  10, 2024, June  25, 2024 and September 10, 2024;

• Our definitive proxy statement on Schedule 14A filed with the SEC on May 9, 2024 and amended on May 21, 2024; and

• The description of our ordinary shares and ADSs contained in our Registration Statement on Form 8-A, as filed with the SEC under Section 12(b) of the Exchange Act on May 25, 2021, including any amendment or report filed for the purpose of updating such description (File No. 001-40445), including Exhibit 4.3 to our Annual Report on Form 10-K for the year ended December 31, 2021.

All reports and other documents we subsequently file pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act on or after the date of this prospectus supplement, including our annual Proxy Statement on Schedule 14A relating to our annual general meeting of shareholders, until the earlier of the date on which all of the securities registered hereunder have been sold or the registration statement of which this prospectus supplement and the accompanying prospectus is a part has been withdrawn, but excluding any information furnished to, rather than filed with, the SEC, will also be incorporated by reference into this prospectus supplement and deemed to be part of this prospectus supplement from the date of the filing of such reports and documents.

We will provide to each person at their request, including any beneficial owner, to whom a prospectus is delivered, a copy of any or all of the reports or documents that have been incorporated by reference into this prospectus supplement but not delivered with this prospectus supplement free of charge. We will provide these reports upon written or oral request at no cost to the requester. Please direct your request, either in writing or by telephone, to the following address and telephone number:

Centessa Pharmaceuticals plc

3rd Floor

1 Ashley Road

Altrincham

Cheshire WA14 2DT

United Kingdom

+1 (617) 468 5770

You may also access these documents on our website, http://www.centessa.com. The information contained on, or that can be accessed through, our website is not a part of this prospectus supplement. We have included our website address in this prospectus supplement solely as an inactive textual reference.

The information incorporated by reference is deemed to be part of this prospectus supplement, and subsequent information that we file with the SEC will automatically update and supersede that information. Any statement

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contained in this prospectus supplement or contained in a document incorporated or deemed to be incorporated by reference into this prospectus supplement or the accompanying prospectus will be deemed to be modified or superseded to the extent that a statement contained in this prospectus supplement or the accompanying prospectus or any subsequently filed supplement hereto or thereto, or document deemed to be incorporated by reference into this prospectus supplement or the accompanying prospectus, modifies or supersedes such statement.

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PROSPECTUS

Ordinary Shares

American Depositary Shares representing Ordinary Shares

Debt Securities

Warrants

Units

We may offer and sell from time to time our ordinary shares, each of which may be represented by one American Depositary Share; senior or subordinated debt securities; warrants to purchase any securities that may be sold under this prospectus; units or any combination of these securities as described in this prospectus. We will describe in a prospectus supplement the securities we are offering and selling, as well as the specific terms of the securities. We may also authorize one or more free writing prospectuses to be provided to you in connection with each offering of the securities. Any prospectus supplement and related free writing prospectuses may also add, update or change information contained in this prospectus. For more detailed information, see “Plan of Distribution.”.

We may offer these securities in amounts, at prices and on terms determined at the time of offering. We may sell the securities directly to you, through agents, or through underwriters and dealers on or off the Nasdaq Global Select Market. If we use agents, underwriters or dealers to sell the securities, we will name them and describe their compensation in a prospectus supplement. You should read this prospectus and the accompanying prospectus supplement and any free writing prospectus, as well as documents incorporated by reference into this prospectus, carefully before you invest.

Our American Depositary Shares representing ordinary shares are traded on The Nasdaq Global Select Market under the symbol “CNTA”. A separate Registration Statement on Form F-6 for the registration of American Depositary Shares issuable upon deposit of the ordinary shares was previously filed with the Securities and Exchange Commission and was effective on May 27, 2021 (Registration No. 333-256385). If we decide to list any of these other securities on a national securities exchange upon issuance, the applicable prospectus supplement to this prospectus will identify the exchange and the date when we expect trading to begin. On September 10, 2024, the closing price of our American Depositary Shares on The Nasdaq Global Select Market was $14.58 per share.

We are an “emerging growth company” under federal securities laws and are subject to reduced public company disclosure standards.

Investing in our securities involves certain risks. See “Risk Factors” beginning on page 5 of this prospectus and under any similar headings in the applicable prospectus supplement and any related free writing prospectus and in the documents that are incorporated by reference into this prospectus or the applicable prospectus supplement, as well as “Special Note Regarding Forward-Looking Statements on page 6 of this prospectus, for certain risks you should consider. You should read the entire prospectus and any applicable prospectus supplement carefully before you make your investment decision.

Neither the Securities and Exchange Commission nor any state or other securities commission or other regulatory body has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is September 11, 2024

Table of Contents

	Page
ABOUT THIS PROSPECTUS		1
PROSPECTUS SUMMARY		3
RISK FACTORS		5
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS		6
SECURITIES WE MAY OFFER		9
DESCRIPTION OF SHARE CAPITAL AND ARTICLES OF ASSOCIATION		10
DESCRIPTION OF AMERICAN DEPOSITARY SHARES		31
DESCRIPTION OF DEBT SECURITIES		43
DESCRIPTION OF WARRANTS		56
DESCRIPTION OF UNITS		57
TAXATION		58
USE OF PROCEEDS		59
PLAN OF DISTRIBUTION		60
LEGAL MATTERS		63
EXPERTS		64
SERVICE OF PROCESS AND ENFORCEMENT OF LIABILITIES		65
WHERE YOU CAN FIND MORE INFORMATION		67
INCORPORATION BY REFERENCE		68

ABOUT THIS PROSPECTUS

This prospectus is part of an automatic shelf registration statement on Form S-3 that we filed with the U.S. Securities and Exchange Commission (the “SEC”) under the Securities Act of 1933, as amended, which we refer to as the Securities Act.

Under this shelf registration process, we may offer the securities described in this prospectus from time to time in one or more offerings, at prices and on terms to be determined by market conditions at the time of offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities.

Registration of the securities covered by this prospectus does not mean that these securities will necessarily be offered or sold. As of the date of filing this registration statement, we have no specific plans for selling the securities registered hereunder.

A prospectus supplement may include a discussion of risks or other special considerations applicable to us or the offered securities. A prospectus supplement or any free writing prospectus may also add, update or change information in this prospectus that may contain material information relating to these offerings. If there is any inconsistency between the information in this prospectus and the applicable prospectus supplement, you must rely on the information in the prospectus supplement. Please carefully read both this prospectus, including the information incorporated by reference into this prospectus, and the applicable prospectus supplement or any free writing prospectus together with additional information described under the heading “Where You Can Find More Information.” This prospectus may not be used to offer or sell any securities unless accompanied by a prospectus supplement.

The registration statement containing this prospectus, including exhibits to the registration statement, provides additional information about us and the securities offered under this prospectus. The registration statement can be read at the SEC website mentioned under the heading “Where You Can Find More Information.”

We may sell the securities directly to or through underwriters, dealers or agents. We and our underwriters or agents, reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities through underwriters or agents, we will include in the applicable prospectus supplement:

• the names of those underwriters or agents;

• applicable fees, discounts and commissions to be paid to them;

• details regarding over-allotment options, if any; and

• the net proceeds to us.

We have not authorized any broker-dealer, salesperson or other person to give any information or to make any representation other than those contained or incorporated by reference in this prospectus and the accompanying supplement to this prospectus. You must not rely upon any information or representation not contained or incorporated by reference in this prospectus or the accompanying prospectus supplement. This prospectus and the accompanying supplement to this prospectus and any free writing prospectus do not constitute an offer to sell or the solicitation of an offer to buy securities, nor do this prospectus and the accompanying supplement to this prospectus constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation. The information contained in this prospectus and the accompanying prospectus supplement speaks only as of their respective dates and may not reflect subsequent changes in our business, financial condition, results of operations and prospects even though this prospectus and any accompanying prospectus supplement is delivered or securities are sold on a later date.

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We own various trademark registrations and applications, and unregistered trademarks, including our name and our corporate logo. All other trade names, trademarks and service marks of other companies appearing in this prospectus are the property of their respective holders. Solely for convenience, the trademarks and trade names in this prospectus may be referred to without the ^® and ^™ symbols, but such references should not be construed as any indicator that their respective owners will not assert, to the fullest extent under applicable law, their rights thereto. We do not intend to use or display other companies’ trademarks and trade names to imply a relationship with, or endorsement or sponsorship of us by, any other companies.

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PROSPECTUS SUMMARY

This summary only highlights the more detailed information appearing elsewhere in this prospectus or incorporated by reference in this prospectus. It may not contain all of the information that is important to you. You should carefully read the entire prospectus and the documents incorporated by reference in this prospectus before deciding whether to invest in our securities.

Unless otherwise indicated or the context requires otherwise, in this prospectus and any prospectus supplement hereto, references to “Centessa,” “the Company,” “our company,” “we,” “us” and “our” mean Centessa Pharmaceuticals plc, a public limited company incorporated under the laws of England and Wales.

Overview

We are a clinical-stage pharmaceutical company that aims to discover and develop medicines that are transformational for patients. Our most advanced programs include a hemophilia program, an orexin agonist program for the treatment of narcolepsy and other sleep-wake disorders, and an immuno-oncology program focused on our LockBody^® technology platform. We operate with the conviction that each of our programs has the potential to change the current treatment paradigm and establish a new standard of care.

Corporate Information

Centessa Pharmaceuticals plc is registered with the Registrar of Companies in England and Wales under number 12973576. Our UK registered office is at 3rd Floor, 1 Ashley Road, Altrincham, Cheshire, United Kingdom, WA14 2DT and our US headquarters is at One Federal Street, 38^th Floor, Boston, MA 02110 and our phone number in the US is +1.617.468.5770. Our website address is http://www.centessa.com. The information contained on, or that can be accessed through, our website is not incorporated by reference in this prospectus supplement and you should not consider it part of this prospectus.

Our UK business is operated by Centessa Pharmaceuticals (UK) Limited, (“CPUK”), (formerly Centessa Limited) directly and, in respect of the SerpinPC program, through its wholly owned UK subsidiary, ApcinteX Limited. In mid-2023, we implemented a corporate consolidation of our UK businesses in order to simplify our administrative operations, obtain operational efficiencies and generate administrative cost savings and improve the overall control environment. This has resulted in the business and assets of our UK subsidiaries, Z Factor Limited, Centessa Pharmaceuticals (Morphogen-IX) Limited, Capella Bioscience Ltd, LockBody Therapeutics Ltd, Inexia Limited, Centessa Pharmaceuticals (Orexia) Limited and Janpix Limited being transferred to CPUK. Subsequently, on December 26, 2023, Inexia Limited, Janpix Limited, Ultrahuman Two Limited and Ultrahuman Four Limited were dissolved using the voluntary strike off procedure in sections 1003 to 1011 of the UK Companies Act 2006. We intend to dissolve Z Factor Limited, Centessa Pharmaceuticals (Morphogen-IX) Limited, Capella Bioscience Ltd, LockBody Therapeutics Ltd, and Centessa Pharmaceuticals (Orexia) Limited over the coming months using the voluntary strike off procedure in sections 1003 to 1011 of the UK Companies Act 2006. CPUK is a wholly owned subsidiary of Centessa Pharmaceuticals plc. CPUK was incorporated in 2020 under the laws of England and Wales with primary operations in the United Kingdom. ApcinteX Limited was incorporated in 2014 under the laws of England and Wales with primary operations in the United Kingdom. Our U.S. subsidiaries are Centessa Pharmaceuticals Holdings, Inc., incorporated in 2022 under the laws of Delaware, Centessa Biosciences, Inc. (formerly known as Palladio Biosciences, Inc.), incorporated in 2015 under the laws of Delaware and Centessa Pharmaceuticals LLC (formerly known as Centessa Pharmaceuticals, Inc.), incorporated in 2020 under the laws of Delaware. We refer to CPUK, ApcinteX Limited, Z Factor Limited, Centessa Pharmaceuticals (Morphogen-IX) Limited, Capella Bioscience Ltd, LockBody Therapeutics Ltd, and Centessa Pharmaceuticals (Orexia) Limited, Centessa Pharmaceuticals Holdings, Inc., Centessa Biosciences, Inc. and Centessa Pharmaceuticals LLC as the “Centessa Subsidiaries”.

3

Implications of Being an Emerging Growth Company

We are an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act (JOBS Act) enacted in April 2012. For so long as we remain an emerging growth company, we are permitted and intend to rely on certain exemptions from various public company reporting requirements, including not being required to have our internal control over financial reporting audited by our independent registered public accounting firm pursuant to Section 404(b) of the Sarbanes-Oxley Act of 2002, reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements, exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and any golden parachute payments not previously approved.

We will remain an emerging growth company until the earlier to occur of (1) the last day of the fiscal year that is five years following the closing of our initial public offering in 2021, (2) the last day of the fiscal year in which we have total annual gross revenues of at least $1.235 billion, (3) the last day of the fiscal year in which we are deemed to be a “large accelerated filer,” under the rules of the U.S. Securities and Exchange Commission (the “SEC”) which means the market value of our equity securities that is held by non-affiliates exceeds $700 million as of the prior June 30th after we have been subject to the SEC’s periodic reporting requirements for at least twelve calendar months and have filed at least one annual report, and (4) the date on which we have issued more than $1.0 billion in non-convertible debt during the prior three-year period.

In addition, the JOBS Act provides that an emerging growth company can take advantage of an extended transition period for complying with new or revised accounting standards. This provision allows an emerging growth company to delay the adoption of some accounting standards until those standards would otherwise apply to private companies. We are electing to utilize the extended transition period and, as a result, will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for private companies.

Even after we no longer qualify as an emerging growth company, we may still qualify as a “smaller reporting company” if the market value of our ordinary shares held by non-affiliates is below $250 million (or $700 million if our annual revenue is less than $100 million) as of June 30 in any given year, which would allow us to take advantage of many of the same exemptions from disclosure requirements, including reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements.

4

RISK FACTORS

Before making an investment decision, you should carefully consider the risks described under “Risk Factors” in the applicable prospectus supplement, together with all of the other information appearing in this prospectus or incorporated by reference into this prospectus and any applicable prospectus supplement, including our most recent annual report on Form 10-K and in our most recent quarterly report on Form 10-Q, as well as any amendments thereto reflected in subsequent filings with the SEC, which are incorporated by reference into this prospectus in their entirety, and other documents we file with the SEC that are deemed incorporated by reference into this prospectus. See “Where You Can Find More Information” for information about how to obtain a copy of these documents. Our business, financial condition or results of operations could be materially adversely affected by any of these risks. The trading price of our securities could decline due to any of these risks, and you may lose all or part of your investment. This prospectus and the incorporated documents also contain forward-looking statements that involve risks and uncertainties. Our actual results could differ materially from those anticipated in these forward-looking statements as a result of certain factors, including the risks mentioned elsewhere in this prospectus.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference into it contain express or implied forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, that involve substantial risks and uncertainties. In some cases, forward-looking statements may be identified by the words “may,” “might,” “will,” “could,” “would,” “should,” “expect,” “intend,” “plan,” “objective,” “anticipate,” “believe,” “estimate,” “predict,” “potential,” “continue,” “ongoing,” “aim,” “seek,” “strive,” or the negative of these terms, or other comparable terminology intended to identify statements about the future. These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, levels of activity, performance or achievements to be materially different from the information expressed or implied by these forward-looking statements. The forward-looking statements and opinions contained in this prospectus are based upon information available to our management as of the date of this prospectus, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Forward-looking statements contained in this prospectus include, but are not limited to, statements about:

• the initiation, timing, progress and results (preliminary, interim or final) of our preclinical studies and clinical trials, and our research and development programs including SerpinPC, LB101, other LockBody candidates, the LockBody technology platform, ORX750, ORX142, and other orexin agonist molecules;

• our ability to execute our research and clinical development plans and our expectations on and the timing thereof;

• our expectations and ability to advance our pipeline and product candidates into, and successfully complete, clinical trials;

• our ability to identify screen, recruit and maintain a sufficient number of, or any, subjects in our existing and anticipated studies or clinical trials including PRESent-5, the observational feeder study, PRESent-2 and PRESent-3 and studies or trials of LB101, and any other LockBody candidates, ORX750 and other orexin agonist molecules;

• our ability to differentiate SerpinPC, LB101, ORX750, other orexin agonist molecules, and other LockBody candidates from other treatment options;

• the development and therapeutic potential of SerpinPC, LB101, other LockBody candidates, the LockBody technology platform, ORX750 and other orexin agonist molecules;

• our expectations relating to the further clinical development of ORX750 the exploration of higher doses in the Phase 1 first-in-human, clinical trial of ORX750, the initiation of Phase 2 study of ORX750, including the predicted timing of enrollment, the predicted efficacious doses of ORX750 and our ability to successfully conduct our clinical development of ORX750;

• whether preclinical and initial clinical results of our programs, including ORX750, SerpinPC and LB101, will be predictive of results of further clinical trials;

• the safety and tolerability profile of our product candidates;

• our reliance on the success of our product candidates and our pipeline programs;

• our ability to discover and develop transformational medicines for patients including identifying and advancing additional product candidates into clinical development;

• the timing or likelihood of regulatory filings and approvals;

• the impact of inflation on increasing costs of labor, research, manufacturing and clinical trial expenses;

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• the impact of the Russia-Ukraine war, the Middle East conflict(s) and tensions in U.S.-China relations on our business and operations;

• the commercialization of our product candidates, if approved;

• our ability to develop sales and marketing capabilities;

• the pricing, coverage and reimbursement of our product candidates, if approved;

• the implementation of our business model, strategic plans for our business, product candidates and technology;

• the scope of protection we are able to establish and maintain for intellectual property rights covering our product candidates and technology;

• our ability to operate our business without infringing the intellectual property rights and proprietary technology of third parties;

• cost associated with prosecuting and maintaining our intellectual property and with defending intellectual property infringement, product liability and other claims;

• legal and regulatory developments in the United States, the European Union, the United Kingdom and other jurisdictions;

• estimates of our expenses, future revenues, capital requirements and our needs for additional financing;

• the potential benefits of strategic collaboration agreements and our ability to negotiate and enter into strategic arrangements;

• our ability to identify collaboration opportunities and to establish and maintain collaborations;

• our ability to judiciously manage and allocate our cash;

• our expectations on our anticipated cash runway;

• our ability to obtain additional funding;

• our ability to fulfill our obligations under the Note Purchase Agreement, as amended, with Three Peaks Capital Solutions Aggregator Fund, and Cocoon SA LLC, an affiliate of Oberland Capital Management LLC;

• the rate and degree of market acceptance of any approved products;

• developments relating to our competitors and our industry, including competing therapies and our ability to respond to such developments;

• our ability to effectively manage our anticipated growth;

• our ability to attract and retain qualified employees and key personnel;

• our expectations regarding the period during which we qualify as a smaller reporting company and as an emerging growth company under the JOBS Act;

• statements regarding future revenue, hiring plans, expenses, capital expenditures, capital requirements and share performance;

• our expected use of proceeds of our IPO and any additional capital raise;

• the future trading price of the ADSs and impact of securities analysts’ reports on these prices; and

• other risks and uncertainties, including those listed under the caption “Risk Factors.”

You should refer to the section titled “Risk Factors” in this prospectus and described in any prospectus supplement and our periodic filings with the SEC incorporated by reference in this prospectus or any prospectus

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supplement for a discussion of important factors that may cause our actual results to differ materially from those expressed or implied by our forward-looking statements. As a result of these factors, we cannot be assured that the forward-looking statements in this prospectus will prove to be accurate. Furthermore, if our forward-looking statements prove to be inaccurate, the inaccuracy may be material. In light of the significant uncertainties in these forward-looking statements, these statements should not be regarded as a representation or warranty by us or any other person that we will achieve our objectives and plans in any specified time frame, or at all. We undertake no obligation to publicly update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

You should read this prospectus, any applicable prospectus supplement, together with the documents we have filed with the SEC that are incorporated by reference and any free writing prospectus that we may authorize for use in connection with a specific offering completely and with the understanding that our actual future results may be materially different from what we expect. We qualify all of our forward-looking statements by these cautionary statements.

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SECURITIES WE MAY OFFER

We may offer our ordinary shares, each of which may be represented by one ADS, various series of senior or subordinated debt securities, warrants to purchase any such securities, units, or any combination of these securities from time to time under this prospectus at prices and on terms to be determined by market conditions at the time of offering. Each time we offer a type or series of securities, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities.

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DESCRIPTION OF SHARE CAPITAL AND ARTICLES OF ASSOCIATION

The following describes our issued share capital, summarizes the material provisions of our articles of association and highlights certain differences in corporate law in the United Kingdom and the United States. Please note that this summary is not intended to be exhaustive. For further information, please refer to the full version of our articles of association, which are incorporated by reference herein. We encourage you to read our articles of association (the “Articles”) and the applicable provisions of English law for additional information.

We were incorporated pursuant to the laws of England and Wales as United Medicines Biopharma Limited on October 26, 2020 and then renamed as Centessa Pharmaceuticals Limited on February 17, 2021. We are registered with the Registrar of Companies in England and Wales under number 12973576, and our registered office is at 3rd Floor, 1 Ashley Road, Altrincham, Cheshire, United Kingdom, WA14 2DT.

Certain resolutions were passed by our shareholders at our 2021 general shareholder meeting, including in respect of:

• general authorization of our directors for purposes of section 551 of the Companies Act to issue our shares and grant rights to subscribe for or convert any securities into our shares up to a maximum aggregate nominal amount of £305,000 for a period of five years; and

• empowering of our directors pursuant to section 570 of the Companies Act to issue equity securities for cash pursuant to the section 551 authority referred to above as if the statutory preemption rights under section 561(1) of the Companies Act did not apply to such allotments.

On May 14, 2021, we re-registered Centessa Pharmaceuticals Limited as a public limited company with the name Centessa Pharmaceuticals plc.

Issued Share Capital

As of June 30, 2024, the Company’s issued share capital was 113,177,764 ordinary shares with a nominal value of £0.002 per share.

Ordinary Shares

In accordance with our Articles, the following summarizes the rights of holders of our ordinary shares:

• each holder of our ordinary shares is entitled to one vote per ordinary share on all matters to be voted on by shareholders generally;

• the holders of the ordinary shares shall be entitled to receive notice of, attend, speak and vote at our general meetings; and

• holders of our ordinary shares are entitled to receive such dividends as are recommended by our directors and declared by our shareholders.

Deferred Shares

In accordance with our Articles, the following summarizes the rights of holders of our deferred shares created as part of the reverse share split:

• holders of our deferred shares are not entitled to vote on any shareholder matters, or receive notice of, attend, speak or vote at our general meetings or receives copies of our reports, accounts, circulars or other documents sent to our shareholders;

• holders of our deferred shares shall not be entitled to receive any dividends or participation in our profits;

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• in the event of a winding up or our liquidation, the deferred shares shall only participate in our surplus assets to the extent that each ordinary share has first received the amount paid up on that ordinary shares plus the sum of £1,000,000 in respect of each ordinary shares; and

• the deferred shares shall not be transferable, save as in accordance with the limited circumstances set out in our Articles.

Registered Shares

We are required by the Companies Act to keep a register of our shareholders. Under English law, the ordinary shares and deferred shares are deemed to be issued when the name of the shareholder is entered in our share register. The share register therefore is prima facie evidence of the identity of our shareholders, and the shares that they hold. The share register generally provides limited, or no, information regarding the ultimate beneficial owners of our ordinary shares. Our share register is maintained by our registrar.

Holders of our ADSs are not treated as our shareholders and their names are therefore not entered in our share register. The depositary, the custodian or their nominees are the holder of the ordinary shares underlying our ADSs. Holders of our ADSs have a right to receive the ordinary shares underlying their ADSs. For discussion on our ADSs and ADS holder rights, see “Description of American Depositary Shares” below.

Under the Companies Act, we must enter an allotment of shares in our share register as soon as practicable and in any event within two months of the allotment. We also are required by the Companies Act to register a transfer of shares (or give the transferee notice of and reasons for refusal as the transferee may reasonably request) as soon as practicable and in any event within two months of receiving notice of the transfer.

We, any of our shareholders or any other affected person may apply to the court for rectification of the share register if:

• the name of any person, without sufficient cause, is wrongly entered in or omitted from our register of members; or

• there is a default or unnecessary delay in entering on the register the fact of any person having ceased to be a member or on which we have a lien, provided that such delay does not prevent dealings in the shares taking place on an open and proper basis.

Preemptive Rights

English law generally provides shareholders with preemptive rights when new shares are issued for cash; however, it is possible for the articles of association, or shareholders in general meeting representing at least 75% of our ordinary shares present (in person or by proxy) and voting at that general meeting, to exclude preemptive rights. Such an exclusion of preemptive rights may be for a maximum period of up to five years from the date of adoption of the articles of association, if the exclusion is contained in the articles of association, or from the date of the shareholder resolution, if the exclusion is by shareholder resolution. In either case, this exclusion would need to be renewed by our shareholders upon its expiration (i.e., at least every five years). On June 25, 2024, our shareholders approved the disapplication of preemptive rights for a period of five years expiring on June 24, 2029 by way of a special resolution of our shareholders and replaced the existing power passed on May 20, 2021. This included the disapplication of preemption rights in relation to the allotment of our ordinary shares or to grant rights to subscribe for or to convert any security into shares without first offering them to existing shareholders in proportion to their existing holdings up to an aggregate maximum nominal amount of £100,740. This disapplication will need to be renewed upon expiration (i.e., at least every five years) to remain effective, but may be sought more frequently for additional five-year terms (or any shorter period).

Distributions and Dividends

Under the Companies Act, before a company can lawfully make a distribution or dividend, it must ensure that it has sufficient distributable reserves, as determined on a non-consolidated basis. The basic rule is that a

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company’s profits available for the purpose of making a distribution are its accumulated, realized profits, so far as not previously utilized by distribution or capitalization, less its accumulated, realized losses, so far as not previously written off in a reduction or reorganization of capital duly made. The requirement to have sufficient distributable reserves before a distribution or dividend can be paid applies to us and to each of our subsidiaries that has been incorporated under English law.

As a public company, an additional capital maintenance requirement is imposed on us to ensure that the net worth of the Company is at least equal to the amount of its capital. A public company can only make a distribution:

• if, at the time that the distribution is made, the amount of its net assets (that is, the total excess of assets over liabilities) is not less than the total of its called up share capital and undistributable reserves; and

• if, and to the extent that, the distribution itself, at the time that it is made, does not reduce the amount of its net assets to less than that total.

Disclosure of Interest in Shares

Pursuant to Part 22 of the Companies Act, a company is empowered by notice in writing to require any person whom the company knows to be, or has reasonable cause to believe to be, interested in the company’s shares or at any time during the three years immediately preceding the date on which the notice is issued to have been so interested, within a reasonable time to disclose to the company details of that person’s interest and (so far as is within such person’s knowledge) details of any other interest that subsists or subsisted in those shares.

If a shareholder defaults in supplying the company with the required details in relation to the shares in question (the “Default Shares”), the shareholder shall not be entitled to vote or exercise any other right conferred by membership in relation to general meetings. Where the Default Shares represent 0.25% or more of the issued shares of the class in question, the directors may direct that:

• any dividend or other money payable in respect of the Default Shares shall be retained by the company without any liability to pay interest on it when such dividend or other money is finally paid to the shareholder; and/or

• no transfer by the relevant shareholder of shares (other than a transfer approved in accordance with the provisions of the company’s articles of association) may be registered (unless such shareholder is not in default and the transfer does not relate to default shares).

Purchase of Own Shares

English law permits a public limited company to purchase its own shares out of the distributable profits of the company or the proceeds of a fresh issue of shares made for the purpose of financing the purchase, subject to complying with procedural requirements under the Companies Act and provided that its articles of association do not prohibit it from doing so. Our Articles do not prohibit us from purchasing our own shares. A public limited company must not purchase its own shares if, as a result of the purchase, there would no longer be any issued shares of the company other than redeemable shares or shares held as treasury shares.

Any such purchase will be either a “market purchase” or “off market purchase,” each as defined in the Companies Act. A “market purchase” is a purchase made on a “recognized investment exchange (other than an overseas exchange) as defined in the UK Financial Services and Markets Act 2000 (“FSMA”). An “off market purchase” is a purchase that is not made on a “recognized investment exchange.” Both “market purchases” and “off market purchases” require prior shareholder approval by way of an ordinary resolution. In the case of an “off market purchase,” a company’s shareholders, other than the shareholders from whom the company is purchasing shares, must approve the terms of the contract to purchase shares and in the case of a “market purchase,” the shareholders must approve the maximum number of shares that can be purchased and the maximum and

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minimum prices to be paid by the company. Both resolutions authorizing “market purchases” and “off-market purchases” must specify a date, not later than five years after the passing of the resolution, on which the authority to purchase is to expire.

Nasdaq is an “overseas exchange” for the purposes of the Companies Act and does not fall within the definition of a “recognized investment exchange” for the purposes of FSMA and any purchase made by us would need to comply with the procedural requirements under the Companies Act that regulate “off market purchases.”

A share buy back by a company of its shares will give rise to U.K. stamp duty reserve tax and stamp duty at the rate of 0.5% of the amount or value of the consideration payable by the company (rounded up to the next £5.00), and such stamp duty reserve tax or duty will be paid by the company. The charge to stamp duty reserve tax will be canceled or, if already paid, repaid (generally with interest), where a transfer instrument for stamp duty purposes has been duly stamped within six years of the charge arising (either by paying the stamp duty or by claiming an appropriate relief) or if the instrument is otherwise exempt from stamp duty.

Our Articles do not have conditions governing changes to our capital which are more stringent than those required by law.

Shareholder Rights

Certain rights granted under the Companies Act, including the right to requisition a general meeting or require a resolution to be put to shareholders at the annual general meeting, are only available to our members. For English law purposes, our members are the persons who are registered as the owners of the legal title to the shares and whose names are recorded in our register of members. In the case of shares held in a settlement system operated by the Depository Trust Company (“DTC”), the registered member will be DTC’s nominee, Cede & Co. If a person who holds their ADSs in DTC wishes to exercise certain of the rights granted under the Companies Act, they may be required to first take steps to withdraw their ADSs from the settlement system operated by DTC and become the registered holder of the shares in our register of members. A withdrawal of shares from DTC may have tax implications.

Registration Rights

The holders of up to 50,034,030 of our ordinary shares and all ordinary shares held by the entities affiliated with Medicxi and the entities affiliated with Index Ventures (the “Registrable Securities”) are entitled to rights with respect to the registration of these securities under the Securities Act of 1933, as amended (the “Securities Act”). These rights are provided under the terms of a registration rights agreement between us and holders of our convertible preferred shares, which were converted into ordinary shares in connection with our initial public offering in June 2021. The registration rights agreement includes demand registration rights, short-form registration rights and piggyback registration rights.

Demand Registration Rights

The holders of a majority of the outstanding Registrable Securities are entitled to demand registration rights. Under the terms of the registration rights agreement, we will be required, upon the written request of holders of a majority of these securities to file a registration statement, with respect to at least 40% of the Registrable Securities then outstanding (or a lesser percentage, if the anticipated aggregate offering price would exceed $10.0 million) and use best efforts to effect the registration of all or a portion of these shares for public resale. We are required to effect only two registrations pursuant to this provision of the registration rights agreement.

Short-Form Registration Rights

Pursuant to the registration rights agreement, if we are eligible to file a registration statement on Form F-3 or Form S-3, upon the written request of holders of at least 10% of the outstanding Registrable Securities having an

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anticipated aggregate offering price of at least $4.0 million, we will be required to effect a registration of such Registrable Securities. We are required to effect only two registrations in any twelve month period pursuant to this provision of the registration rights agreement. The right to have such shares registered on Form F-3 or Form S-3 is further subject to other specified conditions and limitations.

Piggyback Registration Rights

Pursuant to the registration rights agreement, if we register any of our securities either for our own account or for the account of other security holders, other than in connection with our initial public offering or a registration for any employee benefit plan, corporate reorganization, or the offer or sale of debt securities, the holders of the Registrable Securities (for so long as they are a party to the registration rights agreement) are entitled to include their shares in the registration. Subject to certain exceptions contained in the registration rights agreement, we and the underwriters may limit the number of Registrable Securities included in the underwritten offering to the number of shares which we and the underwriters determine in our sole discretion will not jeopardize the success of the offering.

Indemnification

Our registration rights agreement contains customary cross-indemnification provisions, under which we are obligated to indemnify holders of registrable securities in the event of material misstatements or omissions in the registration statement attributable to us, and they are obligated to indemnify us for material misstatements or omissions attributable to them.

Expiration of Registration Rights

The registration rights granted under the registration rights agreement will terminate on the earlier of (i) the fourth anniversary of the completion of our initial public offering (ii) such time as all relevant ordinary shares may be sold pursuant to Rule 144 without limitation during a 90 day period without registration and (iii) the closing of a share sale, as such term is defined in our Articles.

Articles of Association

Our Articles were approved by our shareholders on May 20, 2021 and were adopted with effect from the completion of our initial public offering. A summary of the terms of the Articles is set out below. The summary below is not a complete copy of the terms of the Articles.

The Articles contain no specific restrictions on our purpose and therefore, by virtue of section 31(1) of the Companies Act, our purpose is unrestricted.

The Articles contain, among other things, provisions to the following effect:

Share Capital

Our share capital consists of ordinary shares and deferred shares. We may, in accordance with section 551 of the Companies Act, be authorized by our shareholders to generally and unconditionally allot our shares or grant rights to subscribe for or convert any security into our shares by way of an ordinary resolution or if no ordinary resolution is passed or so far as the resolution does not make specific provision, as the board of directors may determine, including shares which are to be redeemed, or are liable to be redeemed at our option or the option of the holder of such shares. However, an amendment to our Articles, which requires the passing of a special resolution, will be required to issue any shares other than ordinary shares or deferred shares.

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Voting

The holders of ordinary shares have the right to receive notice of, and to vote at, our general meetings. Subject to any other provisions of the Articles and without prejudice to any special rights, privileges or restrictions as to voting attached to any shares forming part of our share capital, each holder of our ordinary shares who is present in person (or, in the case of a corporation, by representative) or by proxy at a general meeting on a show of hands has one vote and, on a poll, every such holder who is present in person (or, being a corporation, by representative) or by proxy has one vote in respect of every ordinary share held by him.

Variation of Rights

Whenever our share capital is divided into different classes of shares, the special rights attached to any class may be varied or abrogated either with the consent in writing of the holders of three-fourths in nominal value of the issued shares of that class or with the sanction of a special resolution passed at a general meeting of the holders of the shares of that class, and may be so varied and abrogated whilst the Company is a going concern.

Dividends

We may, subject to the provisions of the Companies Act and the Articles, by ordinary resolution from time to time declare dividends to be paid to shareholders not exceeding the amount recommended by our board of directors. Subject to the provisions of the Companies Act, in so far as, in the board of directors’ opinions, our profits justify such payments, the board of directors may declare interim dividends (including any dividend at a fixed rate) as appears to our board of directors to be justified by our profits available for distribution. Except as provided otherwise by the rights attached to shares, all dividends may be declared or paid in any currency. Our board of directors may decide the rate of exchange for any currency conversions that may be required and how any costs involved in such conversions are to be met.

Any dividend unclaimed after a period of 12 years from the date such dividend was declared or became payable shall, if the board of directors resolve, be forfeited and shall cease to remain owing by us. Unless otherwise provided by the rights attached to the share, no dividend or other monies payable on or in respect of a share shall bear interest as against us.

Liquidation Preference

On a distribution of assets on a liquidation, the surplus assets remaining after payment of liabilities shall be distributed among the holders of ordinary shares pro rata to the number of ordinary shares held by them, irrespective of the amount paid or credited as paid on any ordinary share.

Transfer of Ordinary Shares

Subject to the restrictions in the Articles, each member may transfer all or any of his shares which are in certificated form by means of an instrument of transfer in any usual form or in any other form which the board of directors may approve. Each member may transfer all or any of his shares which are in uncertificated form by means of a “relevant system” (i.e., the CREST System) in such manner provided for, and subject as provided in, the CREST Regulations.

The board of directors may, in its absolute discretion, refuse to register a transfer of certificated shares unless:

(i) it is for a share which is fully paid up;

(ii) it is for a share upon which the company has no lien;

(iii) it is only for one class of share;

(iv) it is in favor of a single transferee or no more than four joint transferees;

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(v) it is duly stamped or is duly certificated or otherwise shown to the satisfaction of the board of directors to be exempt from stamp duty; and

(vi) it is delivered for registration to the registered office of the company (or such other place as the board of directors may determine), accompanied (except in the case of a transfer by a person to whom the company is not required by law to issue a certificate and to whom a certificate has not been issued or in the case of a renunciation) by the certificate for the shares to which it relates and such other evidence as the board of directors may reasonably require to prove the title of the transferor (or person renouncing) and the due execution of the transfer or renunciation by him or, if the transfer or renunciation is executed by some other person on his behalf, the authority of that person to do so.

The board of directors shall not refuse to register any transfer of partly paid shares in respect of which ADSs are admitted to Nasdaq on the grounds that they are partly paid shares in circumstances where such refusal would prevent dealings in such shares from taking place on an open and proper basis.

The board of directors may refuse to register a transfer of uncertificated shares in any circumstances that are allowed or required by the CREST Regulations and the CREST System.

Allotment of Shares and Preemption Rights

Subject to the Companies Act and to any rights attached to existing shares, any share may be issued with or have attached to it such rights and restrictions as the company may by ordinary resolution determine, or if no ordinary resolution has been passed or so far as the resolution does not make specific provision, as the board of directors may determine (including shares which are to be redeemed, or are liable to be redeemed at the option of the company or the holder of such shares). However, an amendment to the Articles, which requires the passing of a special resolution, will be required to issue any shares other than ordinary shares.

In accordance with section 551 of the Companies Act, the board of directors may be generally and unconditionally authorized to exercise all the powers of the company to allot shares or grant rights to subscribe for or to convert any security into shares up to an aggregate nominal amount equal to the amount stated in the relevant ordinary resolution authorizing such allotment. On June 25, 2024, our shareholders approved a resolution authorizing the board of directors to allot new shares or to grant rights to subscribe for or to convert any security into shares in the Company up to a maximum aggregate nominal amount of £100,740. This authority replaced the authorities passed on May 20, 2021, runs for five years and will expire on June 24, 2029.

Pursuant to of section 561 of the Companies Act, shareholders are granted preemptive rights when new shares are issued for cash. However, it is possible for the Articles, or shareholders at a general meeting representing at least 75% of our ordinary shares present (in person or by proxy) and eligible to vote at that general meeting, to disapply these preemptive rights. Such a disapplication of preemption rights may be a maximum period of up to five years from the date of the shareholder resolution. In either case, this disapplication would need to be renewed by our shareholders upon its expiration (i.e. at least every five years).

On June 25, 2024, our shareholders approved the disapplication of preemptive rights for a period of five years expiring on June 24, 2029 by way of a special resolution of our shareholders and replaced the existing power passed on May 20, 2021. This included the disapplication of preemption rights in relation to the allotment of our ordinary shares or to grant rights to subscribe for or to convert any security into shares without first offering them to existing shareholders in proportion to their existing holdings up to an aggregate maximum nominal amount of £100,740. This disapplication will need to be renewed upon expiration (i.e., at least every five years) to remain effective, but may be sought more frequently for additional five-year terms (or any shorter period).

Alteration of Share Capital

The company may, in accordance with the Companies Act, by ordinary resolution consolidate all of its share capital into shares of larger nominal value than its existing shares, or cancel any shares which, at the date of the

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ordinary resolution, have not been taken or agreed to be taken by any person and diminish the amount of its share capital by the nominal amount of shares so cancelled, or sub-divide its shares, or any of them, into shares of smaller nominal value.

The company may, in accordance with the Companies Act, reduce or cancel its share capital or any capital redemption reserve or share premium account in any manner and with and subject to any conditions, authorities and consents required by law.

Board of Directors

Appointment of directors

Unless otherwise determined by the Company by ordinary resolution, the number of directors (other than any alternate directors) shall not be less than two but there shall be no maximum number of directors.

Subject to the Articles and the Companies Act, the Company may by ordinary resolution appoint a person who is willing to act as a director and the board of directors shall have power at any time to appoint any person who is willing to act as a director, in both cases either to fill a vacancy or as an addition to the existing board of directors.

The Articles provide that our board of directors is divided into three classes, each of which will consist, as nearly as possible, of one-third of the total number of directors constituting our entire board and which will serve staggered three-year terms. At each annual general meeting, the successors of directors whose terms then expire will be elected to serve from the time of election and qualification until the third annual meeting following election.

At every subsequent annual general meeting any director who either (i) has been appointed by the board of directors since the last annual general meeting or (ii) was not appointed or reappointed at one of the preceding two annual general meetings, must retire from office and may offer themselves for reappointment by the shareholders by ordinary resolution.

Proceedings of directors

Subject to the provisions of the Articles, the board of directors may regulate their proceedings as they deem appropriate. A director may, and the secretary at the request of a director shall, call a meeting of the directors.

The quorum for a meeting of the board of directors shall be fixed from time to time by a decision of the board of directors, but it must never be less than two directors (or duly appointed alternative directors) and unless otherwise fixed, it is two directors (or duly appointed alternative directors).

Questions and matters requiring resolution arising at a meeting shall be decided by a majority of votes of the participating directors, with each director having one vote. In the case of an equality of votes, the chairman will only have a casting vote or second vote (unless the chairperson is not entitled to vote on the resolution in question).

Directors’ compensation

Directors shall be entitled to receive such remuneration as the board of directors shall determine for their services to the company as directors, and for any other service which they undertake for the Company. The directors shall be entitled to reasonable additional remuneration (whether by way of salary, commission, participation in profits or otherwise) for any special duties or services performed or rendered to us, as determined by our board of directors, and in respect of any employment or executive office. The directors shall also be entitled to be paid all

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reasonable expenses properly incurred by them in connection with their attendance at meetings of shareholders or class meetings, board of director or committee meetings or otherwise in connection with the exercise of their powers and the discharge of their responsibilities in relation to the Company.

Conflicts of interest

The board of directors may, in accordance with the requirements in the Articles, authorize any matter proposed to them by any director which would, if not authorized, involve a director breaching his duty under the Companies Act, to avoid conflicts of interests.

A director seeking authorization in respect of such conflict shall declare to the board of directors the nature and extent of his interest in a conflict as soon as is reasonably practicable. The director shall provide the board of directors with such details of the matter as are necessary for the board of directors to decide how to address the conflict together with such additional information as may be requested by the board of directors.

Any authorization by the board of directors will be effective only if:

(i) to the extent permitted by the Companies Act, the matter in question shall have been proposed by any director for consideration in the same way that any other matter may be proposed to the directors under the provisions of the Articles;

(ii) any requirement as to the quorum for consideration of the relevant matter is met without counting the conflicted director and any other conflicted director; and

(iii) the matter is agreed to without the conflicted director voting or would be agreed to if the conflicted director’s and any other interested director’s vote is not counted.

Permitted interests

Under the Articles, certain transactions which would otherwise give rise to a conflict are considered to be permitted interests of our directors. In the event that these permitted interests arise, the director in question will still count towards the quorum requirements of the relevant meeting and be entitled to vote on resolutions relating to such permitted interests, including but not limited to the following matters:

(i) the giving by such director of any security, guarantee or indemnity for any money or any liability which such director, or any other person, has lent or obligations such director or any other person has undertaken at the request, or for the benefit, of us or any of our subsidiary undertakings;

(ii) the giving of any security, guarantee or indemnity to any other person for a debt or obligation which is owed by us or any of our subsidiary undertakings, to that other person if such director has taken responsibility for some or all of that debt or obligation. Such director can take this responsibility by giving a guarantee, indemnity or security;

(iii) a proposal or contract relating to an offer of any shares or debentures or other securities for subscription or purchase by us or any of our subsidiary undertakings, if such director takes part because such director is a holder of shares, debentures or other securities, or if such director takes part in the underwriting or sub-underwriting of the offer;

(iv) any arrangement for the benefit of our employees or the employees of any of our subsidiary undertakings which only gives such director benefits which are also generally given to employees to whom the arrangement relates;

(v) any arrangement involving any other company if such director (together with any person connected with such director) has an interest of any kind in that company (including an interest by holding any position in that company or by being a shareholder of that company). This does not apply if such

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director knows that that such director has a relevant interest in a company. A company shall be deemed to be one in which such director has a relevant interest if and so long as (but only if and so long as) such director is to their knowledge (either directly or indirectly) the holder of or beneficially interested in one percent or more of any class of the equity share capital of that company (calculated exclusive of any shares of that class in that company held as treasury shares) or of the voting rights available to shareholders of that company;

(vi) a contract relating to insurance which we can buy or renew for the benefit of our directors or a group of people which includes our directors; and

(vii) a contract relating to a pension, superannuation or similar scheme or a retirement, death, disability benefits scheme or employees’ share scheme which gives such director benefits which are also generally given to the employees to whom the scheme relates.

A director is not permitted to vote (or count towards the quorum) on a resolution relating to their own appointment or the settlement or variation of the terms of their appointment to an office or place of profit with us, or any other company in which we have an interest.

Directors’ Indemnity

Subject to the provisions of the Companies Act, every director, secretary or other officer of the company (other than an auditor) shall be indemnified against all costs, charges, losses, damages and liabilities incurred by him in the actual purported exercise or discharge of his duties or exercise of his powers or otherwise in relation to them. This indemnity includes any liability incurred by a director in defending any civil or criminal proceedings in which judgment is given in that director’s favor or the director is acquitted or the proceedings are otherwise disposed of without any finding or admission of any material breach of duty on his part and we may provide the director with funds to meet expenditure incurred in connection with the proceedings set out above.

General Meetings

The Company must convene and hold general meetings within the six-month period beginning with the day following our accounting reference date in accordance with the Companies Act. Under the Companies Act, an annual general meeting must be called by notice of at least 21 clear days and a general meeting must be called by notice of at least 14 clear days.

No business shall be transacted at any general meeting unless a quorum is present when the meeting proceeds to business, but the absence of a quorum shall not preclude the choice or appointment of a chairman of the meeting which shall not be treated as part of the business of the meeting. Save as otherwise provided by the Articles, two shareholders present in person or by proxy and entitled to vote shall be a quorum for all purposes.

Choice of forum/governing law

The Articles provide that the courts of England and Wales will be the exclusive forum for resolving all shareholder complaints other than shareholder complaints asserting a cause of action arising under the Securities Act and the Exchange Act, for which, unless we consent by ordinary resolution to the selection of an alternative forum, the United States District Court for the Southern District of New York will be the exclusive forum. As a company incorporated in England and Wales, the choice of the courts of England and Wales as our exclusive forum for resolving all shareholder complaints, other than complaints arising under the Securities Act and the Exchange Act, allows us to more efficiently and affordably respond to such actions, and provides consistency in the application of the laws of England and Wales to such actions.

Similarly, we have selected the United States District Court for the Southern District of New York as our exclusive forum for resolving shareholder complaints arising under the Securities Act and the Exchange Act in order to more efficiently and affordably respond to such claims.

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This choice of forum also provides both us and our shareholders with a forum that is familiar with and regularly reviews cases involving U.S. securities law. Although we believe this choice of forum benefits us by providing increased consistency in the application of U.S. securities law for the specified types of action, it may have the effect of discouraging lawsuits against our directors and officers. Any person or entity purchasing or otherwise acquiring any interest in our ordinary shares will be deemed to have notice of and consented to the provisions of the Articles, including the exclusive forum provision. However, it is possible that a court could find our forum selection provision to be inapplicable or unenforceable. The enforceability of similar exclusive forum provisions (including exclusive federal forum provisions for actions, suits or proceedings asserting a cause of action arising under the Securities Act) in other companies’ organizational documents has been challenged in legal proceedings, and there is uncertainty as to whether courts would enforce the exclusive forum provisions in the Articles. Additionally, our shareholders cannot waive compliance with the federal securities laws and the rules and regulations thereunder.

Borrowing Powers

Subject to the Articles and the Companies Act, the board of directors may exercise all of the powers of the Company to:

(a) borrow money;

(b) indemnify and guarantee;

(c) mortgage or charge;

(d) create and issue debentures and other securities; and

(e) give security either outright or as collateral security for any debt, liability or obligation of the company or of any third party.

Capitalization of Profits

The directors may, if they are so authorized by an ordinary resolution of the shareholders, decide to capitalize any undivided profits of the company (whether or not they are available for distribution), or any sum standing to the credit of the company’s share premium account or capital redemption reserve. The directors may also, subject to the aforementioned ordinary resolution, appropriate any sum which they so decide to capitalize to the persons who would have been entitled to it if it were distributed by way of dividend and in the same proportions.

Limitation on Owning Securities

The Articles do not restrict in any way the ownership or voting of our shares by non-residents.

Uncertificated Shares

Subject to the Companies Act, the board of directors may permit title to shares of any class to be issued or held otherwise than by a certificate and to be transferred by means of a “relevant system” (i.e., the CREST System) without a certificate.

The board of directors may take such steps as it sees fit in relation to the evidencing of and transfer of title to uncertificated shares, any records relating to the holding of uncertificated shares and the conversion of uncertificated shares to certificated shares, or vice-versa.

The company may by notice to the holder of an uncertificated share, require that share to be converted into certificated form.

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The board of directors may take such other action that the board considers appropriate to achieve the sale, transfer, disposal, forfeiture, re-allotment or surrender of an uncertified share or otherwise to enforce a lien in respect of it.

Other Relevant Laws and Regulations

Takeover Code

We believe that, as of the date of this prospectus, our place of central management and control is not in the United Kingdom (or the Channel Islands or the Isle of Man) for the purposes of the jurisdictional criteria of the UK City Code on Takeovers and Mergers (the “Takeover Code”). Accordingly, we believe that we are not currently subject to the Takeover Code and, as a result, our shareholders are not currently entitled to the benefit of certain takeover offer protections provided under the Takeover Code, including the rules regarding mandatory takeover bids.

In the event that this changes, or if the interpretation and application of the Takeover Code by the Panel on Takeovers and Mergers (the “Takeover Panel”), changes (including changes to the way in which the Takeover Panel assesses the application of the Takeover Code to English companies whose shares are listed outside of the United Kingdom), the Takeover Code may apply to us in the future.

Mandatory bid

The Takeover Code provides a framework within which takeovers of companies subject to it are conducted. In particular, the Takeover Code contains certain rules in respect of mandatory offers. Under the Takeover Code, where:

• any person, together with persons acting in concert with him, acquires, whether by a series of transactions over a period of time or not, an interest in shares which (taken together with shares in which he is already interested, and in which persons acting in concert with him are interested) carry 30% or more of the voting rights of a company; or

• any person who, together with persons acting in concert with him, is interested in shares which in the aggregate carry not less than 30% of the voting rights of a company but does not hold shares carrying more than 50% of such voting rights and such person, or any person acting in concert with him, acquires an interest in any other shares which increases the percentage of shares carrying voting rights in which he is interested

such person shall, except in limited circumstances, be obliged to extend offers, on the basis set out in Rules 9.3, 9.4 and 9.5 of the Takeover Code, to the holders of any class of equity share capital, whether voting or non-voting, and also to the holders of any other class of transferable securities carrying voting rights. Offers for different classes of equity share capital must be comparable; the Takeover Panel should be consulted in advance in such cases.

An offer under Rule 9 of the Takeover Code must be in cash and at the highest price paid for any interest in the shares by the person required to make an offer or any person acting in concert with him during the 12 months prior to the announcement of the offer.

Under the Takeover Code, “persons acting in concert” comprises persons who pursuant to an agreement or understanding (whether formal or informal and whether or not in writing) actively cooperate, through the acquisition by them of an interest in shares in a company, to obtain or consolidate control of the company. “Control” means holding, or aggregate holdings, of an interest in shares carrying 30% or more of the voting rights of the company, irrespective of whether the holding or holdings give de facto control.

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Squeeze-Out

Under sections 979 to 982 of the Companies Act, if an offeror were to acquire, or unconditionally contract to acquire, not less than 90% of the ordinary shares of the company, it could then compulsorily acquire the remaining 10%. It would do so by sending a notice to outstanding shareholders telling them that it will compulsorily acquire their shares, provided that no such notice may be served after the end of: (a) the period of three months beginning with the day after the last day on which the offer can be accepted; or (b) if earlier, and the offer is not one to which section 943(1) of the Companies Act applies, the period of six months beginning with the date of the offer.

Six weeks following service of the notice, the offeror must send a copy of it to the company together with the consideration for the ordinary shares to which the notice relates, and an instrument of transfer executed on behalf of the outstanding shareholder(s) by a person appointed by the offeror.

The company will hold the consideration on trust for the outstanding shareholders.

Sell-out

Sections 983 to 985 of the Companies Act also give minority shareholders in the company a right to be bought out in certain circumstances by an offeror who has made a takeover offer. If a takeover offer relating to all the ordinary shares of the Company is made at any time before the end of the period within which the offer could be accepted and the offeror held or had agreed to acquire not less than 90% of the ordinary shares, any holder of

shares to which the offer related who had not accepted the offer could by a written communication to the offeror require it to acquire those shares. The offeror is required to give any shareholder notice of his right to be bought out within one month of that right arising. The offeror may impose a time limit on the rights of minority shareholders to be bought out, but that period cannot end less than three months after the end of the acceptance period, or, if longer a period of three months from the date of the notice.

If a shareholder exercises his rights, the offeror is bound to acquire those shares on the terms of the offer or on such other terms as may be agreed.

Differences in Corporate Law

The applicable provisions of the Companies Act differ from laws applicable to U.S. corporations and their shareholders. Set forth below is a summary of certain differences between the provisions of the Companies Act applicable to us and the General Corporation Law of the State of Delaware relating to shareholders’ rights and protections. This summary is not intended to be a complete discussion of the respective rights and it is qualified in its entirety by reference to Delaware law and the laws of England and Wales.

	England and Wales	Delaware
Number of Directors	Under the Companies Act, a public limited company must have at least two directors and the number of directors may be fixed by or in the manner provided in a company’s articles of association.	Under Delaware law, a corporation must have at least one director and the number of directors shall be fixed by or in the manner provided in the bylaws.

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	England and Wales	Delaware
Removal of Directors	Under the Companies Act, shareholders may remove a director without cause by an ordinary resolution (which is passed by a simple majority of those voting in person or by proxy at a general meeting) irrespective of any provisions of any service contract the director has with the company, provided 28 clear days’ notice of the resolution has been given to the company and its shareholders. On receipt of notice of an intended resolution to remove a director, the company must forthwith send a copy of the notice to the director concerned. Certain other procedural requirements under the Companies Act must also be followed, such as allowing the director to make representations against his or her removal either at the meeting or in writing.	Under Delaware law, any director or the entire board of directors may be removed, with or without cause, by the holders of a majority of the shares then entitled to vote at an election of directors, except (i) unless the certificate of incorporation provides otherwise, in the case of a corporation whose board of directors is classified, stockholders may effect such removal only for cause, or (ii) in the case of a corporation having cumulative voting, if less than the entire board of directors is to be removed, no director may be removed without cause if the votes cast against his removal would be sufficient to elect him if then cumulatively voted at an election of the entire board of directors, or, if there are classes of directors, at an election of the class of directors of which he is a part.
Vacancies on the Board of Directors	Under the laws of England and Wales, the procedure by which directors, other than a company’s initial directors, are appointed is generally set out in a company’s articles of association, provided that where two or more persons are appointed as directors of a public limited company by resolution of the shareholders, resolutions appointing each director must be voted on individually unless a resolution has first been unanimously passed confirming that a single resolution appointing two or more directors may be tabled at that meeting.	Under Delaware law, vacancies and newly created directorships may be filled by a majority of the directors then in office (even though less than a quorum) or by a sole remaining director unless (i) otherwise provided in the certificate of incorporation or bylaws of the corporation or (ii) the certificate of incorporation directs that a particular class of stock is to elect such director, in which case a majority of the other directors elected by such class, or a sole remaining director elected by such class, will fill such vacancy.
Annual General Meeting	Under the Companies Act, a public limited company must hold an annual general meeting in each six-month period following the company’s annual accounting reference date. Under the Companies Act, a general meeting of the shareholders of a public limited company may be called by the directors.	Under Delaware law, the annual meeting of stockholders shall be held at such place, on such date and at such time as may be designated from time to time by the board of directors or as provided in the certificate of incorporation or by the bylaws.
General Meeting	Shareholders holding at least 5% of the paid-up capital of the company carrying voting rights at general meetings (excluding any paid up capital held as treasury shares) can require the directors to call a general meeting and, if the directors fail to do so within a certain period, may themselves convene a general meeting.	Under Delaware law, special meetings of the stockholders may be called by the board of directors or by such person or persons as may be authorized by the certificate of incorporation or by the bylaws.

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	England and Wales	Delaware
Notice of General Meetings	Subject to a company’s articles of association providing for a longer period, under the Companies Act, at least 21 clear days’ notice must be given for an annual general meeting and any resolutions to be proposed at the meeting. Subject to a company’s articles of association providing for a longer period, at least 14 clear days’ notice is required for any other general meeting of a public limited company. In addition, certain matters, such as the removal of directors or auditors, require special notice, which is 28 clear days’ notice. The shareholders of a company may in all cases consent to a shorter notice period, the proportion of shareholders’ consent required being 100% of those entitled to attend and vote in the case of an annual general meeting and, in the case of any other general meeting, a majority in number of the members having a right to attend and vote at the meeting, being a majority who together hold not less than 95% in nominal value of the shares giving a right to attend and vote at the meeting.	Under Delaware law, unless otherwise provided in the certificate of incorporation or bylaws, written notice of any meeting of the stockholders must be given to each stockholder entitled to vote at the meeting not less than ten nor more than 60 days before the date of the meeting and shall specify the place, date, hour and purpose or purposes of the meeting.
Quorum	Subject to the provisions of a company’s articles of association, the Companies Act provides that two shareholders present at a meeting (in person, by proxy or by authorized representative under the Companies Act) shall constitute a quorum for companies with more than one member.	The certificate of incorporation or bylaws may specify the number of shares, the holders of which shall be present or represented by proxy at any meeting in order to constitute a quorum, but in no event shall a quorum consist of less than one third of the shares entitled to vote at the meeting. In the absence of such specification in the certificate of incorporation or bylaws, a majority of the shares entitled to vote, present in person or represented by proxy, shall constitute a quorum at a meeting of stockholders.
Proxy	Under the Companies Act, at any meeting of shareholders, a shareholder may designate another person to attend, speak and vote at the meeting on their behalf by proxy.	Under Delaware law, at any meeting of stockholders, a stockholder may designate another person to act for such stockholder by proxy, but no such proxy shall be voted or acted upon after three years from its date, unless the proxy provides for a longer period. A director of a Delaware corporation may not issue a proxy representing the director’s voting rights as a director.

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	England and Wales	Delaware
Issue of New Shares	Under the Companies Act, the directors of a company must not exercise any power to allot shares or grant rights to subscribe for, or to convert any security into, shares unless they are authorized to do so by the company’s articles of association or by an ordinary resolution of the shareholders. Any authorization given must state the maximum amount of shares that may be allotted under it and specify the date on which it will expire, which must be not more than five years from the date the authorization was given. The authority can be renewed by a further resolution of the shareholders.	Under Delaware law, if the company’s certificate of incorporation so provides, the directors have the power to authorize the issuance of additional stock. The directors may authorize capital stock to be issued for consideration consisting of cash, any tangible or intangible property or any benefit to the company or any combination thereof.
Preemptive Rights	Under the Companies Act, “equity securities,” being (i) shares in the company other than shares that, with respect to dividends and capital, carry a right to participate only up to a specified amount in a distribution, referred to as “ordinary shares,” or (ii) rights to subscribe for, or to convert securities into, ordinary shares, proposed to be allotted for cash must be offered first to the existing equity shareholders in the company in proportion to the respective nominal value of their holdings, unless an exception applies or a special resolution to the contrary has been passed by shareholders in a general meeting or the articles of association provide otherwise in each case in accordance with the provisions of the Companies Act.	Under Delaware law, shareholders have no preemptive rights to subscribe to additional issues of stock or to any security convertible into such stock unless, and except to the extent that, such rights are expressly provided for in the certificate of incorporation.
Authority to Allot	Under the Companies Act, the directors of a company must not allot shares or grant rights to subscribe for or convert any security into shares unless an exception applies or an ordinary resolution to the contrary has been passed by shareholders in a general meeting or the articles of association provide otherwise, in each case in accordance with the provisions of the Companies Act.	Under Delaware law, if the corporation’s charter or certificate of incorporation so provides, the board of directors has the power to authorize the issuance of stock. The board may authorize capital stock to be issued for consideration consisting of cash, any tangible or intangible property or any benefit to the corporation or any combination thereof. It may determine the amount of such consideration by approving a formula. In the absence of actual fraud in the transaction, the judgment of the directors as to the value of such consideration is conclusive.

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	England and Wales	Delaware
Liability of Directors and Officers	Under the Companies Act, any provision, whether contained in a company’s articles of association or any contract or otherwise, that purports to exempt a director of a company, to any extent, from any liability that would otherwise attach to him in connection with any negligence, default, breach of duty or breach of trust in relation to the company, is void. Any provision by which a company directly or indirectly provides an indemnity, to any extent, for a director of the company or of an associated company against any liability attaching to him in connection with any negligence, default, breach of duty or breach of trust in relation to the company of which he is a director is also void except as permitted by the Companies Act, which provides exceptions for the company to company against any liability attaching to him in connection with any negligence, default, breach of duty or breach of trust in relation to the company of which he is a director is also void except as permitted by the Companies Act, which provides exceptions for the company to (i) purchase and maintain insurance against such liability; (ii) provide a “qualifying third party indemnity,” or an indemnity against liability incurred by the director to a person other than the company or an associated company or criminal proceedings in which he is convicted; and (iii) provide a “qualifying pension scheme indemnity,” or an indemnity against liability incurred in connection with the company’s activities as trustee of an occupational pension plan.	Under Delaware law, a corporation’s certificate of incorporation may include a provision eliminating or limiting the personal liability of a director to the corporation and its stockholders for damages arising from a breach of fiduciary duty as a director. However, no provision can limit the liability of a director for: •  any breach of the director’s duty of loyalty to the corporation or its stockholders; •  acts or omissions not in good faith or that involve intentional misconduct or a knowing violation of law; •  intentional or negligent payment of unlawful dividends or stock purchases or redemptions; or •  any transaction from which the director derives an improper personal benefit.

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	England and Wales	Delaware
Voting Rights	For a company incorporated under the laws of England and Wales, it is usual for the articles of association to provide that,, unless a poll is demanded by the shareholders of a company or is required by the chairman of the meeting or the company’s articles of association, shareholders shall vote on all resolutions on a show of hands. Under the Companies Act, a poll may be demanded by (i) not fewer than five shareholders having the right to vote on the resolution; (ii) any shareholder(s) representing not less than 10% of the total voting rights of all the shareholders having the right to vote on the resolution (excluding any voting rights attaching to treasury shares); or (iii) any shareholder(s) holding shares in the company conferring a right to vote on the resolution (excluding any voting rights attaching to treasury shares) being shares on which an aggregate sum has been paid up equal to not less than 10% of the total sum paid up on all the shares conferring that right. A company’s articles of association may provide more extensive rights for shareholders to call a poll. Under the laws of England and Wales, an ordinary resolution is passed on a show of hands if it is approved by a simple majority (more than 50%) of the votes cast by shareholders present (in person or by proxy) and entitled to vote. If a poll is demanded, an ordinary resolution is passed if it is approved by holders representing a simple majority of the total voting rights of shareholders present, in person or by proxy, who, being entitled to vote, vote on the resolution. Special resolutions require the affirmative vote of not less than 75% of the votes cast by shareholders present, in person or by proxy, at the meeting. If a poll is demanded, a special resolution is passed if it is approved by holders representing not less than 75% of the total voting rights of shareholders in person or by proxy who, being entitled to vote, vote on the resolution.	Delaware law provides that, unless otherwise provided in the certificate of incorporation, each stockholder is entitled to one vote for each share of capital stock held by such stockholder.

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	England and Wales	Delaware
Shareholder Vote on Certain Transactions	The Companies Act provides for schemes of arrangement, which are arrangements or compromises between a company and any class of shareholders or creditors and used in certain types of reconstructions, amalgamations, capital reorganizations or takeovers. These arrangements require: •  the approval at a shareholders’ or creditors’ meeting convened by order of the court, of a majority in number of shareholders or creditors representing 75% in value of the capital held by, or debt owed to, the shareholders or creditors or class thereof present and voting, either in person or by proxy; and •  the approval of the court.	Generally, under Delaware law, unless the certificate of incorporation provides for the vote of a larger portion of the stock, completion of a merger, consolidation, sale, lease or exchange of all or substantially all of a corporation’s assets or dissolution requires: •  the approval of the board of directors; and •  the approval by the vote of the holders of a majority of the outstanding stock or, if the certificate of incorporation provides for more or less than one vote per share, a majority of the votes of the outstanding stock of the corporation entitled to vote on the matter.
Shareholder Vote on Certain Transactions	The Companies Act provides for schemes of arrangement, which are arrangements or compromises between a company and any class of shareholders or creditors and used in certain types of reconstructions, amalgamations, capital reorganizations or takeovers. These arrangements require: •  the approval at a shareholders’ or creditors’ meeting convened by order of the court, of a majority in number of shareholders or creditors representing 75% in value of the capital held by, or debt owed to, the shareholders or creditors or class thereof present and voting, either in person or by proxy; and •  the approval of the court.	Generally, under Delaware law, unless the certificate of incorporation provides for the vote of a larger portion of the stock, completion of a merger, consolidation, sale, lease or exchange of all or substantially all of a corporation’s assets or dissolution requires: •  the approval of the board of directors; and •  the approval by the vote of the holders of a majority of the outstanding stock or, if the certificate of incorporation provides for more or less than one vote per share, a majority of the votes of the outstanding stock of the corporation entitled to vote on the matter.

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	England and Wales	Delaware
Standard of Conduct for Directors	Under the laws of England and Wales, a director owes various statutory and fiduciary duties to the company, including: •  to act in the way he considers, in good faith, would be most likely to promote the success of the company for the benefit of its members as a whole, and in doing so have regard (amongst other matters) to: (i) the likely consequences of any decision in the long-term, (ii) the interests of the company’s employees,(iii) the need to foster the company’s business relationships with suppliers, customers and others, (iv) the impact of the company’s operations on the community and the environment, (v) the desirability to maintain a reputation for high standards of business conduct, and (vi) the need to act fairly as between members of the company; •  to avoid a situation in which he has, or can have, a direct or indirect interest that conflicts, or possibly conflicts, with the interests of the company; •  to act in accordance with the company’s constitution and only exercise his powers for the purposes for which they are conferred; •  to exercise independent judgment; •  to exercise reasonable care, skill and diligence; •  to accept benefits from a third party conferred by reason of his being a director or doing, or not doing, anything as a director; and •  to declare any interest that he has, whether directly or indirectly, in a proposed or existing transaction or arrangement with the company.	Delaware law does not contain specific provisions setting forth the standard of conduct of a director. The scope of the fiduciary duties of directors is generally determined by the courts of the State of Delaware. In general, directors have a duty to act without self-interest, on a well- informed basis and in a manner they reasonably believe to be in the best interest of the stockholders. Directors of a Delaware corporation owe fiduciary duties of care and loyalty to the corporation and to its shareholders. The duty of care generally requires that a director act in good faith, with the care that an ordinarily prudent person would exercise under similar circumstances. Under this duty, a director must inform himself of all material information reasonably available regarding a significant transaction. The duty of loyalty requires that a director act in a manner he reasonably believes to be in the best interests of the corporation. He must not use his corporate position for personal gain or advantage. In general, but subject to certain exceptions, actions of a director are presumed to have been made on an informed basis, in good faith and in the honest belief that the action taken was in the best interests of the corporation. However, this presumption may be rebutted by evidence of a breach of one of the fiduciary duties. Delaware courts have also imposed a heightened standard of conduct upon directors of a Delaware corporation who take any action designed to defeat a threatened change in control of the corporation. In addition, under Delaware law, when the board of directors of a Delaware corporation approves the sale or break-up of a corporation, the board of directors may, in certain circumstances, have a duty to obtain the highest value reasonably available to the shareholders.

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	England and Wales	Delaware
Stockholder Litigation	Under the laws of England and Wales, generally, the company, rather than its shareholders, is the proper claimant in an action in respect of a wrong done to the company or where there is an irregularity in the company’s internal management. Notwithstanding this general position, the Companies Act provides that (i) a court may allow a shareholder to bring a derivative claim (that is, an action in respect of and on behalf of the company) in respect of a cause of action arising from a director’s negligence, default, breach of duty or breach of trust and (ii) a shareholder may bring a claim for a court order where the company’s affairs have been or are being conducted in a manner that is unfairly prejudicial to some of its shareholders.	Under Delaware law, a stockholder may initiate a derivative action to enforce a right of a corporation if the corporation fails to enforce the right itself. The complaint must: •  state that the plaintiff was a stockholder at the time of the transaction of which the plaintiff complains or that the plaintiffs shares thereafter devolved on the plaintiff by operation of law; and •  allege with particularity the efforts made by the plaintiff to obtain the action the plaintiff desires from the directors and the reasons for the plaintiff’s failure to obtain the action; or •  state the reasons for not making the effort. Additionally, the plaintiff must remain a stockholder through the duration of the derivative suit. The action will not be dismissed or compromised without the approval of the Delaware Court of Chancery.

Stock Exchange Listing

Our ADSs representing ordinary shares are traded on The Nasdaq Global Select Market under the symbol “CNTA”.

Transfer Agent and Registrar of Shares

Our share register is maintained by Computershare Investor Services plc. The share register reflects only record owners of our ordinary shares and deferred shares. Holders of our ADSs are not be treated as our shareholders and their names are therefore not be entered in our share register. The depositary, the custodian or their nominees will be the holder of the ordinary shares underlying our ADSs. Holders of our ADSs have a right to receive the ordinary shares underlying their ADSs.

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DESCRIPTION OF AMERICAN DEPOSITARY SHARES

Citibank, N.A. has agreed to act as the depositary bank for the American Depositary Shares. Citibank’s depositary offices are located at 388 Greenwich Street, New York, New York 10013. ADS represent ownership interests in securities that are on deposit with the depositary bank. ADSs may be represented by certificates that are commonly known as “American Depositary Receipts” or “ADRs.” The depositary bank typically appoints a custodian to safekeep the securities on deposit. In this case, the custodian is Citibank, N.A., London Branch, located at 25 Canada Square, Canary Wharf, London, E14 5LB, United Kingdom.

We have appointed Citibank as depositary bank pursuant to a deposit agreement. A copy of the deposit agreement is on file with the SEC as an exhibit to a Registration Statement on Form F-6. A copy of the deposit agreement may be obtained from the SEC’s website (www.sec.gov). Please refer to Registration Number 333-256385 when retrieving such copy.

We are providing you with a summary description of the material terms of the ADSs and of the material rights of owners of ADSs. Please remember that summaries by their nature lack the precision of the information summarized and that the rights and obligations of an owner of ADSs will be determined by reference to the terms of the deposit agreement and not by this summary. We urge you to review the deposit agreement in its entirety. The portions of this summary description that are italicized describe matters that may be relevant to the ownership of ADSs but that may not be contained in the deposit agreement.

Each ADS represents the right to receive, and to exercise the beneficial ownership interests in, one ordinary share that is on deposit with the depositary bank and/or custodian. An ADS also represents the right to receive, and to exercise the beneficial interests in, any other property received by the depositary bank or the custodian on behalf of the owner of the ADS but that has not been distributed to the owners of ADSs because of legal restrictions or practical considerations. We and the depositary bank may agree to change the ADS-to-Share ratio by amending the deposit agreement. This amendment may give rise to, or change, the depositary fees payable by ADS owners. The custodian, the depositary bank and their respective nominees will hold all deposited property for the benefit of the holders and beneficial owners of ADSs. The deposited property does not constitute the proprietary assets of the depositary bank, the custodian or their nominees. Beneficial ownership in the deposited property will under the terms of the deposit agreement be vested in the beneficial owners of the ADSs. The depositary bank, the custodian and their respective nominees will be the record holders of the deposited property represented by the ADSs for the benefit of the holders and beneficial owners of the corresponding ADSs. A beneficial owner of ADSs may or may not be the holder of ADSs. Beneficial owners of ADSs will be able to receive, and to exercise beneficial ownership interests in, the deposited property only through the registered holders of the ADSs, the registered holders of the ADSs (on behalf of the applicable ADS owners) only through the depositary bank, and the depositary bank (on behalf of the owners of the corresponding ADSs) directly, or indirectly, through the custodian or their respective nominees, in each case upon the terms of the deposit agreement.

Owners of our ADSs will become a party to the deposit agreement and therefore will be bound to its terms and to the terms of any ADR that represents such ADSs. The deposit agreement and the ADR specify our rights and obligations as well as the rights and obligations of owners of ADSs and those of the depositary bank. ADS holders appoint the depositary bank to act on their behalf in certain circumstances. The deposit agreement and the ADRs are governed by New York law. However, our obligations to the holders of ordinary shares will continue to be governed by the laws of England and Wales, which may be different from the laws in the United States.

In addition, applicable laws and regulations may require holders of ADSs to satisfy reporting requirements and obtain regulatory approvals in certain circumstances. holders of ADSs are solely responsible for complying with such reporting requirements and obtaining such approvals. Neither the depositary bank, the custodian, us or any of their or our respective agents or affiliates shall be required to take any actions whatsoever on behalf of holders of ADSs to satisfy such reporting requirements or obtain such regulatory approvals under applicable laws and regulations.

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Owners of ADSs, will not be treated as one of our shareholders and will not have direct shareholder rights. The depositary bank will hold, on the ADS holders’ behalf, the shareholder rights attached to the ordinary shares underlying such ADSs. Owners of ADSs will be able to exercise the shareholders rights for the ordinary shares represented by such ADSs through the depositary bank only to the extent contemplated in the deposit agreement. To exercise any shareholder rights not contemplated in the deposit agreement a holder of ADSs will, as an ADS owner, need to arrange for the cancellation of such ADSs and become a direct shareholder.

The manner in which ADSs are owned (e.g., in a brokerage account vs. as registered holder, or as holder of certificated vs. uncertificated ADSs) may affect the rights and obligations, and the manner in which, and extent to which, the depositary bank’s services are made available to the holder of ADSs. Owners of ADSs may hold their ADSs either by means of an ADR registered in their name, through a brokerage or safekeeping account, or through an account established by the depositary bank in their name reflecting the registration of uncertificated ADSs directly on the books of the depositary bank (commonly referred to as the “direct registration system” or “DRS”). The direct registration system reflects the uncertificated (book-entry) registration of ownership of ADSs by the depositary bank. Under the direct registration system, ownership of ADSs is evidenced by periodic statements issued by the depositary bank to the holders of the ADSs. The direct registration system includes automated transfers between the depositary bank and The Depository Trust Company (“DTC”), the central book-entry clearing and settlement system for equity securities in the United States. If an ADS owner decides to hold their ADSs through their brokerage or safekeeping account, such holder must rely on the procedures of their broker or bank to assert their rights as ADS owner. Banks and brokers typically hold securities such as the ADSs through clearing and settlement systems such as DTC. The procedures of such clearing and settlement systems may limit such holder’s ability to exercise their rights as an owner of ADSs. ADS owners should consult with their broker or bank if they have any questions concerning these limitations and procedures. All ADSs held through DTC will be registered in the name of a nominee of DTC. This summary description assumes holders of ADSs have opted to own the ADSs directly by means of an ADS registered in their name and, as such, we will refer to the owner as the “holder.” This summary also assumes holders will own ADSs at the relevant time.

The registration of the ordinary shares in the name of the depositary bank or the custodian shall, to the maximum extent permitted by applicable law, vest in the depositary bank or the custodian the record ownership in the applicable ordinary shares with the beneficial ownership rights and interests in such ordinary shares being at all times vested with the beneficial owners of the ADSs representing the ordinary shares. The depositary bank or the custodian shall at all times be entitled to exercise the beneficial ownership rights in all deposited property, in each case only on behalf of the holders and beneficial owners of the ADSs representing the deposited property.

Dividends and Distributions

Holder of ADSs generally have the right to receive the distributions we make on the securities deposited with the custodian. Receipt of these distributions by an ADS holder may be limited, however, by practical considerations and legal limitations. Holders of ADSs will receive such distributions under the terms of the deposit agreement in proportion to the number of ADSs held as of the specified record date, after deduction of the applicable fees, taxes and expenses.

Distributions of Cash

Whenever we make a cash distribution for the securities on deposit with the custodian, we will deposit the funds with the custodian. Upon receipt of confirmation of the deposit of the requisite funds, the depositary bank will arrange for the funds received in a currency other than U.S. dollars to be converted into U.S. dollars and for the distribution of the U.S. dollars to the holders, subject to English laws and regulations.

The conversion into U.S. dollars will take place only if practicable and if the U.S. dollars are transferable to the United States. The depositary bank will apply the same method for distributing the proceeds of the sale of any property (such as undistributed rights) held by the custodian in respect of securities on deposit.

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The distribution of cash will be made net of the fees, expenses, taxes and governmental charges payable by holders under the terms of the deposit agreement. The depositary bank will hold any cash amounts it is unable to distribute in a non-interest bearing account for the benefit of the applicable holders and beneficial owners of ADSs until the distribution can be effected or the funds that the depositary bank holds must be escheated as unclaimed property in accordance with the laws of the relevant states of the United States.

Distributions of Shares

Whenever we make a free distribution of ordinary shares for the securities on deposit with the custodian, we will deposit the applicable number of ordinary shares with the custodian. Upon receipt of confirmation of such deposit, the depositary bank will either distribute to holders new ADSs representing the ordinary shares deposited or modify the ADS-to-ordinary-share ratio, in which case each ADS held will represent rights and interests in the additional ordinary shares so deposited. Only whole new ADSs will be distributed. Fractional entitlements will be sold and the proceeds of such sale will be distributed as in the case of a cash distribution.

The distribution of new ADSs or the modification of the ADS-to-ordinary-share ratio upon a distribution of ordinary shares will be made net of the fees, expenses, taxes and governmental charges payable by holders under the terms of the deposit agreement. In order to pay such taxes or governmental charges, the depositary bank may sell all or a portion of the new ordinary shares so distributed.

No such distribution of new ADSs will be made if it would violate a law (e.g., the U.S. securities laws) or if it is not operationally practicable. If the depositary bank does not distribute new ADSs as described above, it may sell the ordinary shares received upon the terms described in the deposit agreement and will distribute the proceeds of the sale as in the case of a distribution of cash.

Distributions of Rights

Whenever we intend to distribute rights to subscribe for additional ordinary shares, we will give prior notice to the depositary bank and we will assist the depositary bank in determining whether it is lawful and reasonably practicable to distribute rights to subscribe for additional ADSs to holders.

The depositary bank will establish procedures to distribute rights to subscribe for additional ADSs to holders and to enable such holders to exercise such rights if it is lawful and reasonably practicable to make the rights available to holders of ADSs, and if we provide all of the documentation contemplated in the deposit agreement (such as opinions to address the lawfulness of the transaction). Holders of ADSs may have to pay fees, expenses, taxes and other governmental charges to subscribe for the new ADSs upon the exercise of their rights. The depositary bank is not obligated to establish procedures to facilitate the distribution and exercise by holders of rights to subscribe for new ordinary shares other than in the form of ADSs.

The depositary bank will not distribute the rights to an ADS holder if:

• We do not timely request that the rights be distributed to such holders or we request that the rights not be distributed to such holders; or

• We fail to deliver satisfactory documents to the depositary bank; or

• It is not reasonably practicable to distribute the rights.

The depositary bank will sell the rights that are not exercised or not distributed if such sale is lawful and reasonably practicable. The proceeds of such sale will be distributed to holders as in the case of a cash distribution. If the depositary bank is unable to sell the rights, it will allow the rights to lapse.

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Elective Distributions

Whenever we intend to distribute a dividend payable at the election of shareholders either in cash or in additional shares, we will give prior notice thereof to the depositary bank and will indicate whether we wish the elective distribution to be made available to ADS holders. In such case, we will assist the depositary bank in determining whether such distribution is lawful and reasonably practicable.

The depositary bank will make the election available to ADS holders only if it is reasonably practicable and if we have provided all of the documentation contemplated in the deposit agreement. In such case, the depositary bank will establish procedures to enable ADS holders to elect to receive either cash or additional ADSs, in each case as described in the deposit agreement.

If the election is not made available to ADS holders, ADS holders will receive either cash or additional ADSs, depending on what a shareholder in England and Wales would receive upon failing to make an election, as more fully described in the deposit agreement.

Other Distributions

Whenever we intend to distribute property other than cash, ordinary shares or rights to subscribe for additional ordinary shares, we will notify the depositary bank in advance and will indicate whether we wish such distribution to be made to ADS holders. If so, we will assist the depositary bank in determining whether such distribution to holders is lawful and reasonably practicable.

If it is reasonably practicable to distribute such property to ADS holders and if we provide to the depositary bank all of the documentation contemplated in the deposit agreement, the depositary bank will distribute the property to the holders in a manner it deems practicable.

The distribution will be made net of fees, expenses, taxes and governmental charges payable by holders under the terms of the deposit agreement. In order to pay such taxes and governmental charges, the depositary bank may sell all or a portion of the property received.

The depositary bank will not distribute the property to holders of ADSs and will sell the property if:

• We do not request that the property be distributed to holders of ADSs or if we request that the property not be distributed to holders of ADSs; or

• We do not deliver satisfactory documents to the depositary bank; or

• The depositary bank determines that all or a portion of the distribution to holders of ADSs is not reasonably practicable.

The proceeds of such a sale will be distributed to holders as in the case of a cash distribution.

Redemption

Whenever we decide to redeem any of the securities on deposit with the custodian, we will notify the depositary bank in advance. If it is practicable and if we provide all of the documentation contemplated in the deposit agreement, the depositary bank will provide notice of the redemption to the holders.

The custodian will be instructed to surrender the shares being redeemed against payment of the applicable redemption price. The depositary bank will convert into U.S. dollars upon the terms of the deposit agreement the redemption funds received in a currency other than U.S. dollars and will establish procedures to enable holders to receive the net proceeds from the redemption upon surrender of their ADSs to the depositary bank. ADS holders may have to pay fees, expenses, taxes and other governmental charges upon the redemption of their ADSs. If less

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than all ADSs are being redeemed, the ADSs to be retired will be selected by lot or on a pro rata basis, as the depositary bank may determine.

Changes Affecting Ordinary Shares

The ordinary shares held on deposit for ADSs may change from time to time. For example, there may be a change in nominal or par value, split-up, cancellation, consolidation or any other reclassification of such ordinary shares or a recapitalization, reorganization, merger, consolidation or sale of assets of the Company.

If any such change were to occur, the ADSs would, to the extent permitted by law and the deposit agreement, represent the right to receive the property received or exchanged in respect of the ordinary shares held on deposit. The depositary bank may in such circumstances deliver new ADSs to the holders, amend the deposit agreement, the ADRs and the applicable Registration Statement(s) on Form F-6, call for the exchange of existing ADSs for new ADSs and take any other actions that are appropriate to reflect as to the ADSs the change affecting the ordinary shares. If the depositary bank may not lawfully distribute such property to the holders of ADSs, the depositary bank may sell such property and distribute the net proceeds to such holders as in the case of a cash distribution.

Issuance of ADSs upon Deposit of Ordinary Shares

The depositary bank may create ADSs on behalf of a holder if such holder or their broker deposit ordinary shares with the custodian. The depositary bank will deliver these ADSs to the person such holder indicates only after such holder pays any applicable issuance fees and any charges and taxes payable for the transfer of the ordinary shares to the custodian. The ability for a holder to deposit ordinary shares and receive ADSs may be limited by U.S. and English legal considerations applicable at the time of deposit.

The issuance of ADSs may be delayed until the depositary bank or the custodian receives confirmation that all required approvals have been given and that the ordinary shares have been duly transferred to the custodian. The depositary bank will only issue ADSs in whole numbers.

When a holder makes a deposit of ordinary shares, such holder will be responsible for transferring good and valid title to the depositary bank. As such, such holder will be deemed to represent and warrant that:

• The ordinary shares are duly authorized, validly issued, fully paid, non-assessable and legally obtained.

• All preemptive (and similar) rights, if any, with respect to such ordinary shares have been validly waived or exercised.

• The holder is duly authorized to deposit the ordinary shares.

• The ordinary shares presented for deposit are free and clear of any lien, encumbrance, security interest, charge, mortgage or adverse claim, and are not, and the ADSs issuable upon such deposit will not be, “restricted securities” (as defined in the deposit agreement).

• The ordinary shares presented for deposit have not been stripped of any rights or entitlements.

If any of the representations or warranties are incorrect in any way, we and the depositary bank may, at the holder’s cost and expense, take any and all actions necessary to correct the consequences of the misrepresentations.

Transfer, Combination and Split Up of ADRs

ADR holders will be entitled to transfer, combine or split up their ADRs and the ADSs evidenced thereby. For transfers of ADRs, a holder will have to surrender the ADRs to be transferred to the depositary bank and also must:

• ensure that the surrendered ADR is properly endorsed or otherwise in proper form for transfer;

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• provide such proof of identity and genuineness of signatures as the depositary bank deems appropriate;

• provide any transfer stamps required by the State of New York or the United States; and

• pay all applicable fees, charges, expenses, taxes and other government charges payable by ADR holders pursuant to the terms of the deposit agreement, upon the transfer of ADRs.

To have ADRs either combined or split up, a holder must surrender the ADRs in question to the depositary bank with their request to have them combined or split up, and such holder must pay all applicable fees, charges and expenses payable by ADR holders, pursuant to the terms of the deposit agreement, upon a combination or split up of ADRs.

Withdrawal of Ordinary Shares Upon Cancellation of ADSs

Holders are entitled to present their ADSs to the depositary bank for cancellation and then receive the corresponding number of underlying ordinary shares at the custodian’s offices. the ability of a holder to withdraw the ordinary shares held in respect of the ADSs may be limited by U.S. and English law considerations applicable at the time of withdrawal. In order to withdraw the ordinary shares represented by ADSs, a holder will be required to pay to the depositary bank the fees for cancellation of ADSs and any charges and taxes payable upon the transfer of the ordinary shares. Holders assume the risk for delivery of all funds and securities upon withdrawal. Once canceled, the ADSs will not have any rights under the deposit agreement.

The depositary bank may ask holders who hold ADSs registered in their name to provide proof of identity and genuineness of any signature and such other documents as the depositary bank may deem appropriate before it will cancel such holders’ ADSs. The withdrawal of the ordinary shares represented by ADSs may be delayed until the depositary bank receives satisfactory evidence of compliance with all applicable laws and regulations. The depositary bank will only accept ADSs for cancellation that represent a whole number of securities on deposit.

ADS holders will have the right to withdraw the securities represented by their ADSs at any time except for:

• Temporary delays that may arise because (i) the transfer books for the ordinary shares or ADSs are closed, or (ii) ordinary shares are immobilized on account of a shareholders’ meeting or a payment of dividends.

• Obligations to pay fees, taxes and similar charges.

• Restrictions imposed because of laws or regulations applicable to ADSs or the withdrawal of securities on deposit.

The deposit agreement may not be modified to impair ADS holders’ right to withdraw the securities represented by their ADSs except to comply with mandatory provisions of law.

Voting Rights

ADS holders generally have the right under the deposit agreement to instruct the depositary bank to exercise the voting rights for the ordinary shares represented by their ADSs. The voting rights of holders of ordinary shares are described in “Description of Share Capital and Articles of Association.”

At our request, the depositary bank will distribute to ADS holders any notice of shareholders’ meeting received from us together with information explaining how to instruct the depositary bank to exercise the voting rights of the securities represented by ADSs. In lieu of distributing such materials, the depositary bank may distribute to holders of ADSs instructions on how to retrieve such materials upon request.

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If the depositary bank timely receives voting instructions from a holder of ADSs, it will endeavor to vote the securities (in person or by proxy) represented by the holder’s ADSs as follows:

• In the event of voting by show of hands, the depositary bank will vote (or cause the custodian to vote) all ordinary shares held on deposit at that time in accordance with the voting instructions received from a majority of holders of ADSs who provide timely voting instructions.

• In the event of voting by poll, the depositary bank will vote (or cause the Custodian to vote) the ordinary shares held on deposit in accordance with the voting instructions received from the holders of ADSs.

Securities for which no voting instructions have been received will not be voted (except as otherwise contemplated in the deposit agreement). The ability of the depositary to carry out voting instructions may be limited by practical and legal limitations and the terms of the securities on deposit. We cannot assure ADS holders that they will receive voting materials in time to enable them to return voting instructions to the depositary in a timely manner.

Fees and Charges

ADS holders are required to pay the following fees under the terms of the deposit agreement:

Service	Fees
•  Issuance of ADSs (e.g., an issuance of ADS upon a deposit of ordinary shares, upon a change in the ADS(s)-to-ordinary-share(s) ratio, or for any other reason), excluding ADS issuances as a result of distributions of shares)	Up to U.S. 5 ¢ per ADS issued
•  Cancellation of ADSs (e.g., a cancellation of ADSs for delivery of deposited property, upon a change in the ADS(s)-to-ordinary-share(s) ratio, or for any other reason)	Up to U.S. 5 ¢ per ADS cancelled
•  Distribution of cash dividends or other cash distributions (e.g., upon a sale of rights and other entitlements)	Up to U.S. 5 ¢ per ADS held
•  Distribution of ADSs pursuant to (i) stock dividends or other free stock distributions, or (ii) exercise of rights to purchase additional ADSs	Up to U.S. 5 ¢ per ADS held
•  Distribution of securities other than ADSs or rights to purchase additional ADSs (e.g., upon a spin-off)	Up to U.S. 5 ¢ per ADS held
•  ADS Services	Up to U.S. 5 ¢ per ADS held on the applicable record date(s) established by the depositary bank
•  Registration of ADS transfers (e.g., upon a registration of the transfer of registered ownership of ADSs, upon a transfer of ADSs into DTC and vice versa, or for any other reason)	Up to U.S. 5 ¢ per ADS (or fraction thereof) transferred
•  Conversion of ADSs of one series for ADSs of another series (e.g., upon conversion of Partial Entitlement ADSs for Full Entitlement ADSs, or	Up to U.S. 5 ¢ per ADS (or fraction thereof) converted
upon conversion of Restricted ADSs (each as defined in the Deposit Agreement) into freely transferable ADSs, and vice versa).

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ADS holders may also be responsible to pay certain charges such as:

• taxes (including applicable interest and penalties) and other governmental charges;

• the registration fees as may from time to time be in effect for the registration of ordinary shares on the share register and applicable to transfers of ordinary shares to or from the name of the custodian, the depositary bank or any nominees upon the making of deposits and withdrawals, respectively;

• certain cable, telex and facsimile transmission and delivery expenses;

• the fees, expenses, spreads, taxes and other charges of the depositary bank and/or service providers (which may be a division, branch or affiliate of the depositary bank) in the conversion of foreign currency;

• the reasonable and customary out-of-pocket expenses incurred by the depositary bank in connection with compliance with exchange control regulations and other regulatory requirements applicable to ordinary shares, ADSs and ADRs; and

• the fees, charges, costs and expenses incurred by the depositary bank, the custodian, or any nominee in connection with the ADR program.

ADS fees and charges for (i) the issuance of ADSs, and (ii) the cancellation of ADSs are charged to the person for whom the ADSs are issued (in the case of ADS issuances) and to the person for whom ADSs are cancelled (in the case of ADS cancellations). In the case of ADSs issued by the depositary bank into DTC, the ADS issuance and cancellation fees and charges may be deducted from distributions made through DTC, and may be charged to the DTC participant(s) receiving the ADSs being issued or the DTC participant(s) holding the ADSs being cancelled, as the case may be, on behalf of the beneficial owner(s) and will be charged by the DTC participant(s) to the account of the applicable beneficial owner(s) in accordance with the procedures and practices of the DTC participants as in effect at the time. ADS fees and charges in respect of distributions and the ADS service fee are charged to the holders as of the applicable ADS record date. In the case of distributions of cash, the amount of the applicable ADS fees and charges is deducted from the funds being distributed. In the case of (i) distributions other than cash and (ii) the ADS service fee, holders as of the ADS record date will be invoiced for the amount of the ADS fees and charges and such ADS fees and charges may be deducted from distributions made to holders of ADSs. For ADSs held through DTC, the ADS fees and charges for distributions other than cash and the ADS service fee may be deducted from distributions made through DTC, and may be charged to the DTC participants in accordance with the procedures and practices prescribed by DTC and the DTC participants in turn charge the amount of such ADS fees and charges to the beneficial owners for whom they hold ADSs. In the case of (i) registration of ADS transfers, the ADS transfer fee will be payable by the ADS holder whose ADSs are being transferred or by the person to whom the ADSs are transferred, and (ii) conversion of ADSs of one series for ADSs of another series, the ADS conversion fee will be payable by the holder whose ADSs are converted or by the person to whom the converted ADSs are delivered.

In the event of refusal to pay the depositary bank fees, the depositary bank may, under the terms of the deposit agreement, refuse the requested service until payment is received or may set off the amount of the depositary bank fees from any distribution to be made to the ADS holder. Certain depositary fees and charges (such as the ADS services fee) may become payable shortly after the closing of the ADS offering. Note that the fees and charges ADS holders may be required to pay may vary over time and may be changed by us and by the depositary bank. ADS holders will receive prior notice of such changes. The depositary bank may reimburse us for certain expenses incurred by us in respect of the ADR program, by making available a portion of the ADS fees charged in respect of the ADR program or otherwise, upon such terms and conditions as we and the depositary bank agree from time to time.

Amendments and Termination

We may agree with the depositary bank to modify the deposit agreement at any time without the consent of ADS holders. We undertake to give holders 30 days’ prior notice of any modifications that would materially prejudice

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any of their substantial rights under the deposit agreement. We will not consider to be materially prejudicial to ADS holders’ substantial rights any modifications or supplements that are reasonably necessary for the ADSs to be registered under the Securities Act or to be eligible for book-entry settlement, in each case without imposing or increasing the fees and charges ADS holders are required to pay. In addition, we may not be able to provide ADS holders with prior notice of any modifications or supplements that are required to accommodate compliance with applicable provisions of law.

ADS holders are bound by the modifications to the deposit agreement if such holder continues to hold their ADSs after the modifications to the deposit agreement become effective. The deposit agreement cannot be amended to prevent ADS holders from withdrawing the ordinary shares represented by their ADSs (except as permitted by law).

We have the right to direct the depositary bank to terminate the deposit agreement. Similarly, the depositary bank may in certain circumstances on its own initiative terminate the deposit agreement. In either case, the depositary bank must give notice to the holders at least 30 days before termination. Until termination, the rights of ADS holders under the deposit agreement will be unaffected.

After termination, the depositary bank will continue to collect distributions received (but will not distribute any such property until an ADS holder requests the cancellation of their ADSs) and may sell the securities held on deposit. After the sale, the depositary bank will hold the proceeds from such sale and any other funds then held for the holders of ADSs in a non-interest bearing account. At that point, the depositary bank will have no further obligations to holders other than to account for the funds then held for the holders of ADSs still outstanding (after deduction of applicable fees, taxes and expenses).

In connection with any termination of the deposit agreement, the depositary bank may make available to owners of ADSs a means to withdraw the ordinary shares represented by ADSs and to direct the depositary of such ordinary shares into an unsponsored American depositary share program established by the depositary bank. The ability to receive unsponsored American depositary shares upon termination of the deposit agreement would be subject to satisfaction of certain U.S. regulatory requirements applicable to the creation of unsponsored American depositary shares and the payment of applicable depositary fees.

Books of Depositary

The depositary bank will maintain ADS holder records at its depositary office. ADS holders may inspect such records at such office during regular business hours but solely for the purpose of communicating with other holders in the interest of business matters relating to the ADSs and the deposit agreement.

The depositary bank will maintain in New York facilities to record and process the issuance, cancellation, combination, split-up and transfer of ADSs. These facilities may be closed from time to time, to the extent not prohibited by law.

Limitations on Obligations and Liabilities

The deposit agreement limits our obligations and the depositary bank’s obligations to holders of ADSs. Please note the following:

• We and the depositary bank are obligated only to take the actions specifically stated in the deposit agreement without negligence or bad faith.

• The depositary bank disclaims any liability for any failure to carry out voting instructions, for any manner in which a vote is cast or for the effect of any vote, provided it acts in good faith and in accordance with the terms of the deposit agreement.

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• The depositary bank disclaims any liability for any failure to determine the lawfulness or practicality of any action, for the content of any document forwarded to a holder of ADSs on our behalf or for the accuracy of any translation of such a document, for the investment risks associated with investing in ordinary shares, for the validity or worth of the ordinary shares, for any tax consequences that result from the ownership of ADSs, for the credit-worthiness of any third party, for allowing any rights to lapse under the terms of the deposit agreement, for the timeliness of any of our notices or for our failure to give notice.

• We and the depositary bank will not be obligated to perform any act that is inconsistent with the terms of the deposit agreement.

• We and the depositary bank disclaim any liability if we or the depositary bank are prevented or forbidden from or subject to any civil or criminal penalty or restraint on account of, or delayed in, doing or performing any act or thing required by the terms of the deposit agreement, by reason of any provision, present or future of any law or regulation, or by reason of present or future provision of any provision of our Articles of Incorporation, or any provision of or governing the securities on deposit, or by reason of any act of God or war or other circumstances beyond our control.

• We and the depositary bank disclaim any liability by reason of any exercise of, or failure to exercise, any discretion provided for in the deposit agreement or in our Articles of Incorporation or in any provisions of or governing the securities on deposit.

• We and the depositary bank further disclaim any liability for any action or inaction in reliance on the advice or information received from legal counsel, accountants, any person presenting ordinary shares for deposit, any holder of ADSs or authorized representatives thereof, or any other person believed by either of us in good faith to be competent to give such advice or information.

• We and the depositary bank also disclaim liability for the inability by a holder to benefit from any distribution, offering, right or other benefit that is made available to holders of ordinary shares but is not, under the terms of the deposit agreement, made available to holders of ADSs.

• We and the depositary bank may rely without any liability upon any written notice, request or other document believed to be genuine and to have been signed or presented by the proper parties.

• We and the depositary bank also disclaim liability for any consequential or punitive damages for any breach of the terms of the deposit agreement.

• No disclaimer of any Securities Act liability is intended by any provision of the deposit agreement.

• Nothing in the deposit agreement gives rise to a partnership or joint venture, or establishes a fiduciary relationship, among us, the depositary bank and any ADS holder.

• Nothing in the deposit agreement precludes Citibank (or its affiliates) from engaging in transactions in which parties adverse to us or the ADS owners have interests, and nothing in the deposit agreement obligates Citibank to disclose those transactions, or any information obtained in the course of those transactions, to us or to the ADS owners, or to account for any payment received as part of those transactions.

As the above limitations relate to our obligations and the depositary’s obligations to ADS holders under the deposit agreement, we believe that, as a matter of construction of the clause, such limitations would likely to continue to apply to ADS holders who withdraw the ordinary shares from the ADS facility with respect to obligations or liabilities incurred under the deposit agreement before the cancellation of the ADSs and the withdrawal of the ordinary shares, and such limitations would most likely not apply to ADS holders who withdraw the ordinary shares from the ADS facility with respect to obligations or liabilities incurred after the cancellation of the ADSs and the withdrawal of the ordinary shares and not under the deposit agreement.

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In any event, ADS holders will not be deemed, by agreeing to the terms of the deposit agreement, to have waived our or the depositary’s compliance with U.S. federal securities laws and the rules and regulations promulgated thereunder. In fact, ADS holders cannot waive our or the depositary’s compliance with U.S. federal securities laws and the rules and regulations promulgated thereunder.

Taxes

ADS holders are responsible for the taxes and other governmental charges payable on the ADSs and the securities represented by the ADSs. We, the depositary bank and the custodian may deduct from any distribution the taxes and governmental charges payable by holders and may sell any and all property on deposit to pay the taxes and governmental charges payable by holders. ADS holders are liable for any deficiency if the sale proceeds do not cover the taxes that are due.

The depositary bank may refuse to issue ADSs, to deliver, transfer, split and combine ADRs or to release securities on deposit until all taxes and charges are paid by the applicable holder. The depositary bank and the custodian may take reasonable administrative actions to obtain tax refunds and reduced tax withholding for any distributions on behalf of the ADS holders. However, holders of ADSs may be required to provide to the depositary bank and to the custodian proof of taxpayer status and residence and such other information as the depositary bank and the custodian may require to fulfill legal obligations. Holders of ADSs are required to indemnify us, the depositary bank and the custodian for any claims with respect to taxes based on any tax benefit obtained for such holder.

Foreign Currency Conversion

The depositary bank will arrange for the conversion of all foreign currency received into U.S. dollars if such conversion is practical, and it will distribute the U.S. dollars in accordance with the terms of the deposit agreement. Holders of ADSs may have to pay fees and expenses incurred in converting foreign currency, such as fees and expenses incurred in complying with currency exchange controls and other governmental requirements.

If the conversion of foreign currency is not practical or lawful, or if any required approvals are denied or not obtainable at a reasonable cost or within a reasonable period, the depositary bank may take the following actions in its discretion:

• Convert the foreign currency to the extent practical and lawful and distribute the U.S. dollars to the holders for whom the conversion and distribution is lawful and practical.

• Distribute the foreign currency to holders for whom the distribution is lawful and practical.

• Hold the foreign currency (without liability for interest) for the applicable holders.

Governing Law/Waiver of Jury Trial

The deposit agreement, the ADRs and the ADSs will be interpreted in accordance with the laws of the State of New York. The rights of holders of ordinary shares (including ordinary shares represented by ADSs) is governed by the laws of England and Wales.

AS A PARTY TO THE DEPOSIT AGREEMENT, HOLDERS OF ADSs IRREVOCABLY WAIVE, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, THEIR RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF THE DEPOSIT AGREEMENT OR THE ADRs AGAINST US AND/OR THE DEPOSITARY BANK.

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The deposit agreement provides that, to the extent permitted by law, ADS holders waive the right to a jury trial of any claim they may have against us or the depositary arising out of or relating to our ordinary shares, the ADSs or the deposit agreement, including any claim under U.S. federal securities laws. If we or the depositary opposed a jury trial demand based on the waiver, the court would determine whether the waiver was enforceable in the facts and circumstances of that case in accordance with applicable case law. However, holders of ADSs will not be deemed, by agreeing to the terms of the deposit agreement, to have waived our or the depositary’s compliance with U.S. federal securities laws and the rules and regulations promulgated thereunder.

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DESCRIPTION OF DEBT SECURITIES

This prospectus describes the general terms and provisions of the debt securities we may offer under this prospectus. When we offer to sell a particular series of debt securities, we will describe the specific terms of the securities in a supplement to this prospectus, including any additional covenants or changes to existing covenants relating to such series. The prospectus supplement also will indicate whether any of the general terms and provisions described in this prospectus apply to a particular series of debt securities. You should read the applicable indenture if you do not fully understand a term or the way we use it in this prospectus.

We may offer senior or subordinated debt securities, which may be convertible. Each series of debt securities may have different terms. The senior debt securities will be issued under one or more senior indentures, dated as of a date prior to such issuance, between us and the trustee identified in the applicable prospectus supplement, as amended or supplemented from time to time. We will refer to any such indenture throughout this prospectus as the “senior indenture.” Any subordinated debt securities will be issued under one or more separate indentures, dated as of a date prior to such issuance, between us and the trustee identified in the applicable prospectus supplement, as amended or supplemented from time to time. We will refer to any such indenture throughout this prospectus as the “subordinated indenture” and to the trustee under the senior or subordinated indenture as the “trustee.” The senior indenture and the subordinated indenture are sometimes collectively referred to in this prospectus as the “indentures.” The indentures will be subject to and governed by the Trust Indenture Act of 1939, as amended. We included copies of the forms of the indentures as exhibits to this registration statement of which this prospectus forms a part.

If we issue debt securities at a discount from their principal amount, then, for purposes of calculating the aggregate initial offering price of the offered securities issued under this prospectus, we will include only the initial offering price of the debt securities and not the principal amount of the debt securities.

We have summarized below the material provisions of the indentures and the debt securities, or indicated which material provisions will be described in the related prospectus supplement. The prospectus supplement relating to any particular securities offered will describe the specific terms of the debt securities, which may be in addition to or different from the general terms summarized in this prospectus. Because the summary in this prospectus and in any prospectus supplement does not contain all of the information that you may find useful, you should read the documents relating to the debt securities that are described in this prospectus or in any applicable prospectus supplement. The statements below are not complete and are subject to, and qualified in their entirety by reference to, all of the provisions of the applicable indenture, as amended or supplemented from time to time. Please read “Where You Can Find More Information” to find out how you can obtain a copy of those documents. Except as otherwise indicated, the terms of the indentures are identical. As used under this caption, the term “debt securities” includes the debt securities being offered by this prospectus and all other debt securities issued by us under the indentures.

General

We expect that the indentures will:

• not limit the amount of debt securities that we may issue;

• allow us to issue debt securities in one or more series;

• not require us to issue all of the debt securities of a series at the same time;

• allow us to reopen a series to issue additional debt securities without the consent of the holders of the debt securities of such series; and

• provide that the debt securities will be unsecured, except as may be set forth in the applicable prospectus supplement.

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Unless we give you different information in the applicable prospectus supplement, the senior debt securities will be unsubordinated obligations and will rank equally with all of our other unsecured and unsubordinated indebtedness. Payments on the subordinated debt securities will be subordinated to the prior payment in full of all of our senior indebtedness, as described under “—Subordination” and in the applicable prospectus supplement.

Each indenture will provide that we may, but need not, designate more than one trustee under an indenture. Any trustee under an indenture may resign or be removed and a successor trustee may be appointed to act with respect to the series of debt securities administered by the resigning or removed trustee. If two or more persons are acting as trustee with respect to different series of debt securities, each trustee shall be a trustee of a trust under the applicable indenture separate and apart from the trust administered by any other trustee. Except as otherwise indicated in this prospectus, any action described in this prospectus to be taken by each trustee may be taken by each trustee with respect to, and only with respect to, the one or more series of debt securities for which it is trustee under the applicable indenture.

The prospectus supplement for each offering will provide the following terms, where applicable:

• the title of the debt securities and whether they are senior or subordinated;

• the aggregate principal amount of the debt securities being offered, the aggregate principal amount of the debt securities outstanding as of the most recent practicable date and any limit on their aggregate principal amount, including the aggregate principal amount of debt securities authorized;

• the price at which the debt securities will be issued, expressed as a percentage of the principal and, if other than the principal amount thereof, the portion of the principal amount thereof payable upon declaration of acceleration of the maturity thereof or, if applicable, the portion of the principal amount of such debt securities that is convertible into ordinary shares or the method by which any such portion shall be determined;

• if convertible, the terms on which such debt securities are convertible, including the initial conversion price or rate and the conversion period and any applicable limitations on the ownership or transferability of ordinary shares received on conversion;

• the date or dates, or the method for determining the date or dates, on which the principal of the debt securities will be payable;

• the fixed or variable interest rate or rates of the debt securities, or the method by which the interest rate or rates is determined;

• the date or dates, or the method for determining the date or dates, from which interest will accrue;

• the dates on which interest will be payable;

• the record dates for interest payment dates, or the method by which we will determine those dates;

• the persons to whom interest will be payable;

• the basis upon which interest will be calculated if other than that of a 360-day year of twelve 30-day months;

• any make-whole amount, which is the amount in addition to principal and interest that is required to be paid to the holder of a debt security as a result of any optional redemption or accelerated payment of such debt security, or the method for determining the make-whole amount;

• the place or places where the principal of, and any premium, or make-whole amount, and interest on, the debt securities will be payable;

• where the debt securities may be surrendered for registration of transfer or conversion or exchange;

• where notices or demands to or upon us in respect of the debt securities and the applicable indenture may be served;

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• the times, prices and other terms and conditions upon which we may redeem the debt securities;

• any obligation we have to redeem, repay or purchase the debt securities pursuant to any sinking fund or analogous provision or at the option of holders of the debt securities, and the times and prices at which we must redeem, repay or purchase the debt securities as a result of such an obligation;

• the currency or currencies in which the debt securities are denominated and payable if other than United States dollars, which may be a foreign currency or units of two or more foreign currencies or a composite currency or currencies and the terms and conditions relating thereto, and the manner of determining the equivalent of such foreign currency in United States dollars;

• whether the principal of, and any premium, or make-whole amount, or interest on, the debt securities of the series are to be payable, at our election or at the election of a holder, in a currency or currencies other than that in which the debt securities are denominated or stated to be payable, and other related terms and conditions;

• whether the amount of payments of principal of, and any premium, or make-whole amount, or interest on, the debt securities may be determined according to an index, formula or other method and how such amounts will be determined;

• whether the debt securities will be in registered form, bearer form or both and (1) if in registered form, the person to whom any interest shall be payable, if other than the person in whose name the security is registered at the close of business on the regular record date for such interest, or (2) if in bearer form, the manner in which, or the person to whom, any interest on the security shall be payable if otherwise than upon presentation and surrender upon maturity;

• any restrictions applicable to the offer, sale or delivery of debt securities in bearer form and the terms upon which securities in bearer form of the series may be exchanged for debt securities in registered form of the series and vice versa if permitted by applicable laws and regulations;

• whether any debt securities of the series are to be issuable initially in temporary global form and whether any debt securities of the series are to be issuable in permanent global form with or without coupons and, if so, whether beneficial owners of interests in any such permanent global security may or shall be required to exchange their interests for other debt securities of the series, and the manner in which interest shall be paid;

• the identity of the depositary for securities in registered form, if such series are to be issuable as a global security;

• the guarantors of each series, if any, and the extent of the guarantees (including provisions relating to seniority, subordination, security and release of the guarantees), if any;

• the date as of which any debt securities in bearer form or in temporary global form shall be dated if other than the original issuance date of the first security of the series to be issued;

• the applicability, if any, of the defeasance and covenant defeasance provisions described in this prospectus or in the applicable indenture;

• whether and under what circumstances we will pay any additional amounts on the debt securities in respect of any tax, assessment or governmental charge and, if so, whether we will have the option to redeem the debt securities in lieu of making such a payment;

• whether and under what circumstances the debt securities being offered are convertible into ordinary shares, including the conversion price or rate or the manner of calculation thereof;

• the circumstances, if any, specified in the applicable prospectus supplement, under which beneficial owners of interests in the global security may obtain definitive debt securities and the manner in which payments on a permanent global debt security will be made if any debt securities are issuable in temporary or permanent global form;

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• any provisions granting special rights to holders of securities upon the occurrence of such events as specified in the applicable prospectus supplement;

• if the debt securities of such series are to be issuable in definitive form only upon receipt of certain certificates or other documents or satisfaction of other conditions, then the form and/or terms of such certificates, documents or conditions;

• the name of the applicable trustee and the nature of any material relationship between the trustee and us or any of our affiliates, and the percentage of debt securities of the class necessary to require the trustee to take action;

• any deletions from, modifications of, or additions to our events of default or covenants and any change in the right of any trustee or any of the holders to declare the principal amount of any of such debt securities due and payable;

• provisions related to the modification of the indentures;

• applicable CUSIP numbers; and

• any other terms of such debt securities not inconsistent with the provisions of the applicable indenture or the Trust Indenture Act.

We may issue debt securities at a discount below their principal amount and provide for less than the entire principal amount thereof to be payable upon declaration of acceleration of the maturity of the debt securities. We refer to any such debt securities throughout this prospectus as “original issue discount securities.” The applicable prospectus supplement will describe the United States federal income tax consequences and other relevant considerations applicable to original issue discount securities.

We also may issue indexed debt securities. Payments of principal, premium and interest on indexed debt securities are determined with reference to the rate of exchange between the currency or currency unit in which the debt security is denominated and any other currency or currency unit specified by us, to the relationship between two or more currencies or currency units or by other similar methods or formulas specified in the prospectus supplement.

Except as described under “—Merger, Consolidation or Sale of Assets” or as may be set forth in any prospectus supplement, the debt securities will not contain any provisions that (1) would limit our ability to incur indebtedness or (2) would afford holders of debt securities protection in the event of (a) a highly leveraged or similar transaction involving us, or (b) a change of control or reorganization, restructuring, merger or similar transaction involving us that may adversely affect the holders of the debt securities. In the future, we may enter into transactions, such as the sale of all or substantially all of our assets or a merger or consolidation, that may have an adverse effect on our ability to service our indebtedness, including the debt securities, by, among other things, substantially reducing or eliminating our assets.

We will provide you with more information in the applicable prospectus supplement regarding any deletions, modifications, or additions to the events of default or covenants that are described below, including any addition of a covenant or other provision providing event risk or similar protection.

Payment

Unless we give you different information in the applicable prospectus supplement, the principal of, and any premium or make-whole amount, and interest on, any series of the debt securities will be payable at the corporate trust office of the trustee. We will provide you with the address of the trustee in the applicable prospectus supplement. We may also pay interest by mailing a check to the address of the person entitled to it as it appears in the applicable register for the debt securities or by wire transfer of funds to that person at an account maintained within the United States.

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All monies that we pay to a paying agent or a trustee for the payment of the principal of, and any premium or make-whole amount, or interest on, any debt security will be repaid to us if unclaimed at the end of two years after the obligation underlying payment becomes due and payable. After funds have been returned to us, the holder of the debt security may look only to us for payment, without payment of interest for the period which we hold the funds.

Denomination, Interest, Registration and Transfer

Unless otherwise described in the applicable prospectus supplement, the debt securities of any series will be issuable in denominations of $1,000 and integral multiples of $1,000.

Subject to the limitations imposed upon debt securities that are evidenced by a computerized entry in the records of a depository company rather than by physical delivery of a note, a holder of debt securities of any series may:

• exchange them for any authorized denomination of other debt securities of the same series and of a like aggregate principal amount and kind upon surrender of such debt securities at the corporate trust office of the applicable trustee or at the office of any transfer agent that we designate for such purpose; and

• surrender them for registration of transfer or exchange at the corporate trust office of the applicable trustee or at the office of any transfer agent that we designate for such purpose.

Every debt security surrendered for registration of transfer or exchange must be duly endorsed or accompanied by a written instrument of transfer satisfactory to the applicable trustee or transfer agent. Payment of a service charge will not be required for any registration of transfer or exchange of any debt securities, but we or the trustee may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith. If in addition to the applicable trustee, the applicable prospectus supplement refers to any transfer agent initially designated by us for any series of debt securities, we may at any time rescind the designation of any such transfer agent or approve a change in the location through which any such transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for such series. We may at any time designate additional transfer agents for any series of debt securities.

Neither we, nor any trustee, will be required to:

• issue, register the transfer of or exchange debt securities of any series during a period beginning at the opening of business 15 calendar days before the day that the notice of redemption of any debt securities selected for redemption is mailed and ending at the close of business on the day of such mailing;

• register the transfer of or exchange any debt security, or portion thereof, so selected for redemption, in whole or in part, except the unredeemed portion of any debt security being redeemed in part; and

• issue, register the transfer of or exchange any debt security that has been surrendered for repayment at the option of the holder, except the portion, if any, of such debt security not to be so repaid.

Merger, Consolidation or Sale of Assets

The indentures provide that we may, without the consent of the holders of any outstanding debt securities, (1) consolidate with, (2) sell, lease or convey all or substantially all of our assets to, or (3) merge with or into, any other entity provided that:

• either we are the continuing entity, or the successor entity, if other than us, assumes the obligations (A) to pay the principal of, and any premium (or make-whole amount) and interest on, all of the debt securities and (B) to duly perform and observe all of the covenants and conditions contained in each indenture;

• after giving effect to the transaction, there is no event of default under the indentures and no event which, after notice or the lapse of time, or both, would become such an event of default, occurs and continues; and

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• an officers’ certificate and legal opinion covering such conditions are delivered to each applicable trustee.

Covenants

Existence. Except as permitted under “—Merger, Consolidation or Sale of Assets,” the indentures require us to do or cause to be done all things necessary to preserve and keep in full force and effect our existence, rights and franchises. However, the indentures do not require us to preserve any right or franchise if we determine that any right or franchise is no longer desirable in the conduct of our business.

Payment of taxes and other claims. The indentures require us to pay, discharge or cause to be paid or discharged, before they become delinquent (1) all taxes, assessments and governmental charges levied or imposed on us, our subsidiaries or our subsidiaries’ income, profits or property, and (2) all lawful claims for labor, materials and supplies which, if unpaid, might by law become a lien upon our property or the property of our subsidiaries. However, we will not be required to pay, discharge or cause to be paid or discharged any such tax, assessment, charge or claim whose amount, applicability or validity is being contested in good faith by appropriate proceedings.

Provision of financial information. The indentures require us to (1) within 15 days of each of the respective dates by which we are required to file our annual reports, quarterly reports and other documents with the SEC, file with the trustee copies of the annual report, quarterly report and other documents that we file with the SEC under Section 13 or 15(d) of the Exchange Act of 1934, as amended (the “Exchange Act”), (2) file with the trustee and the SEC any additional information, documents and reports regarding compliance by us with the conditions and covenants of the indentures, as required, (3) within 30 days after the filing with the trustee, mail to all holders of debt securities, as their names and addresses appear in the applicable register for such debt securities, without cost to such holders, summaries of any documents and reports required to be filed by us pursuant to (1) and (2) above, and (4) supply, promptly upon written request and payment of the reasonable cost of duplication and delivery, copies of such documents to any prospective holder.

Additional covenants. The applicable prospectus supplement will set forth any additional covenants relating to any series of debt securities.

Events of Default, Notice and Waiver

Unless the applicable prospectus supplement states otherwise, when we refer to “events of default” as defined in the indentures with respect to any series of debt securities, we mean:

• default in the payment of any installment of interest on any debt security of such series continuing for 30 calendar days;

• default in the payment of principal of, or any premium, or make-whole amount, on any debt security of such series for five business days at its stated maturity;

• default in making any sinking fund payment as required for any debt security of such series for five business days;

• default in the performance or breach of any covenant or warranty in the debt securities or in the indenture by us continuing for 90 calendar days after written notice as provided in the applicable indenture, but not of a covenant added to the indenture solely for the benefit of a series of debt securities issued thereunder other than such series;

• a default under any bond, debenture, note, mortgage, indenture or instrument:

(1) having an aggregate principal amount in excess of a minimum amount as specified in a prospectus supplement; or

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(2) under which there may be issued, secured or evidenced any existing or later created indebtedness for money borrowed by us or our subsidiaries, if we are directly responsible or liable as obligor or guarantor, if the default results in the indebtedness becoming or being declared due and payable prior to the date it otherwise would have, without such indebtedness having been discharged, or such acceleration having been rescinded or annulled, within 30 days after notice to the issuing company specifying such default. Such notice shall be given to us by the trustee, or to us and the trustee by the holders of at least 10% in principal amount of the outstanding debt securities of that series. The written notice specifying such default and requiring us to cause such indebtedness to be discharged or cause such acceleration to be rescinded or annulled and shall state that such notice is a “Notice of Default” under such indenture;

• bankruptcy, insolvency or reorganization, or court appointment of a receiver, liquidator or trustee of Centessa Therapeutics or any significant subsidiary that, if contested, is not dismissed or stayed within 90 calendar days; and

• any other event of default provided with respect to a particular series of debt securities.

When we use the term “significant subsidiary,” we refer to the meaning ascribed to such term in Rule 1-02 of Regulation S-X promulgated under the Securities Act of 1933, as amended (the “Securities Act”).

If an event of default occurs and is continuing with respect to debt securities of any series outstanding, then the applicable trustee or the holders of 33% or more in principal amount of the debt securities of that series will have the right to declare the principal amount of all the debt securities of that series to be due and payable. If the debt securities of that series are original issue discount securities or indexed securities, then the applicable trustee or the holders of 33% or more in principal amount of the debt securities of that series will have the right to declare the portion of the principal amount as may be specified in the terms thereof to be due and payable. However, at any time after such a declaration of acceleration has been made, but before a judgment or decree for payment of the money due has been obtained by the applicable trustee, the holders of at least a majority in principal amount of outstanding debt securities of such series or of all debt securities then outstanding under the applicable indenture may rescind and annul such declaration and its consequences if:

• we have deposited with the applicable trustee all required payments of the principal, any premium, or make-whole amount, interest and, to the extent permitted by law, interest on overdue installment of interest, plus applicable fees, expenses, disbursements and advances of the applicable trustee; and

• all events of default, other than the non-payment of accelerated principal, or a specified portion thereof, and any premium, or make-whole amount, have been cured or waived.

We expect that the indentures will also provide that the holders of at least a majority in principal amount of the outstanding debt securities of any series or of all debt securities then outstanding under the applicable indenture may, on behalf of all holders, waive any past default with respect to such series and its consequences, except a default:

• in the payment of the principal, any premium, or make-whole amount, or interest;

• in respect of a covenant or provision contained in the applicable indenture that cannot be modified or amended without the consent of the holders of the outstanding debt security that is affected by the default; or

• in respect of a covenant or provision for the benefit or protection of the trustee, without its express written consent.

We expect that the indentures will require each trustee to give notice to the holders of debt securities within 90 days of a default unless such default has been cured or waived. However, the trustee may withhold notice if specified persons of such trustee consider such withholding to be in the interest of the holders of debt securities.

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The trustee may not withhold notice of a default in the payment of principal, any premium or interest on any debt security of such series or in the payment of any sinking fund installment in respect of any debt security of such series.

We expect that the indentures will provide that holders of debt securities of any series may not institute any proceedings, judicial or otherwise, with respect to such indenture or for any remedy under the indenture, unless the trustee fails to act for a period of 60 days after the trustee has received a written request to institute proceedings in respect of an event of default from the holders of 25% or more in principal amount of the outstanding debt securities of such series, as well as an offer of indemnity reasonably satisfactory to the trustee. However, this provision will not prevent any holder of debt securities from instituting suit for the enforcement of payment of the principal of, and any premium, or make-whole amount, and interest on, such debt securities at the respective due dates thereof.

We expect that the indentures will provide that, subject to provisions in each indenture relating to its duties in the case of a default, a trustee has no obligation to exercise any of its rights or powers at the request or direction of any holders of any series of debt securities then outstanding under the indenture, unless the holders have offered to the trustee reasonable security or indemnity. The holders of at least a majority in principal amount of the outstanding debt securities of any series or of all debt securities then outstanding under an indenture shall have the right to direct the time, method and place of conducting any proceeding for any remedy available to the applicable trustee, or of exercising any trust or power conferred upon such trustee. However, a trustee may refuse to follow any direction which:

• is in conflict with any law or the applicable indenture;

• may involve the trustee in personal liability; or

• may be unduly prejudicial to the holders of debt securities of the series not joining the proceeding.

Within 120 days after the close of each fiscal year, we will be required to deliver to each trustee a certificate, signed by one of our several specified officers, stating whether or not that officer has knowledge of any default under the applicable indenture. If the officer has knowledge of any default, the notice must specify the nature and status of the default.

Modification of the Indentures

We expect that the indentures will provide that modifications and amendments may be made only with the consent of the affected holders of at least a majority in principal amount of all outstanding debt securities issued under that indenture. However, no such modification or amendment may, without the consent of each of the affected holders of the debt securities affected by the modification or amendment:

• change the stated maturity of the principal of, or any premium, or make-whole amount, on, or any installment of principal of or interest on, any such debt security;

• reduce the principal amount of, the rate or amount of interest on or any premium, or make-whole amount, payable on redemption of any such debt security;

• reduce the amount of principal of an original issue discount security that would be due and payable upon declaration of acceleration of the maturity thereof or would be provable in bankruptcy, or adversely affect any right of repayment of the holder of any such debt security;

• change the place of payment or the coin or currency for payment of principal of, or any premium, or make-whole amount, or interest on, any such debt security;

• impair the right to institute suit for the enforcement of any payment on or with respect to any such debt security;

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• reduce the percentage in principal amount of any outstanding debt securities necessary to modify or amend the applicable indenture with respect to such debt securities, to waive compliance with particular provisions thereof or defaults and consequences thereunder or to reduce the quorum or voting requirements set forth in the applicable indenture; or

• modify any of the foregoing provisions or any of the provisions relating to the waiver of particular past defaults or covenants, except to increase the required percentage to effect such action or to provide that some of the other provisions may not be modified or waived without the consent of the holder of such debt security.

The holders of a majority in aggregate principal amount of the outstanding debt securities of each series may, on behalf of all holders of debt securities of that series, waive, insofar as that series is concerned, our compliance with material restrictive covenants of the applicable indenture.

We and our respective trustee may make modifications and amendments of an indenture without the consent of any holder of debt securities for any of the following purposes:

• to evidence the succession of another person to us as obligor under such indenture;

• to add to our covenants for the benefit of the holders of all or any series of debt securities or to surrender any right or power conferred upon us in such indenture;

• to add events of default for the benefit of the holders of all or any series of debt securities;

• to add or change any provisions of an indenture (1) to change or eliminate restrictions on the payment of principal of, or premium, or make-whole amount, or interest on, debt securities in bearer form, or (2) to permit or facilitate the issuance of debt securities in uncertificated form, provided that such action shall not adversely affect the interests of the holders of the debt securities of any series in any material respect;

• to change or eliminate any provisions of an indenture, provided that any such change or elimination shall become effective only when there are no debt securities outstanding of any series created prior thereto which are entitled to the benefit of such provision;

• to secure the debt securities;

• to establish the form or terms of debt securities of any series;

• to provide for the acceptance of appointment by a successor trustee or facilitate the administration of the trusts under an indenture by more than one trustee;

• to cure any ambiguity, defect or inconsistency in an indenture, provided that such action shall not adversely affect the interests of holders of debt securities of any series issued under such indenture; and

• to supplement any of the provisions of an indenture to the extent necessary to permit or facilitate defeasance and discharge of any series of such debt securities, provided that such action shall not adversely affect the interests of the holders of the outstanding debt securities of any series.

Voting

We expect the indentures will provide that in determining whether the holders of the requisite principal amount of outstanding debt securities of a series have given any request, demand, authorization, direction, notice, consent or waiver under the indentures or whether a quorum is present at a meeting of holders of debt securities:

• the principal amount of an original issue discount security that shall be deemed to be outstanding shall be the amount of the principal thereof that would be due and payable as of the date of such determination upon declaration of acceleration of the maturity thereof;

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• the principal amount of any debt security denominated in a foreign currency that shall be deemed outstanding shall be the United States dollar equivalent, determined on the issue date for such debt security, of the principal amount or, in the case of an original issue discount security, the United States dollar equivalent on the issue date of such debt security of the amount determined as provided in the preceding bullet point;

• the principal amount of an indexed security that shall be deemed outstanding shall be the principal face amount of such indexed security at original issuance, unless otherwise provided for such indexed security under such indenture; and

• debt securities owned by us or any other obligor upon the debt securities or by any affiliate of ours or of such other obligor shall be disregarded.

The indentures contain provisions for convening meetings of the holders of debt securities of a series. A meeting will be permitted to be called at any time by the applicable trustee, and also, upon request, by us or the holders of at least 25% in principal amount of the outstanding debt securities of such series, in any such case upon notice given as provided in such indenture. Except for any consent that must be given by the holder of each debt security affected by the modifications and amendments of an indenture described above, any resolution presented at a meeting or adjourned meeting duly reconvened at which a quorum is present may be adopted by the affirmative vote of the holders of a majority of the aggregate principal amount of the outstanding debt securities of that series represented at such meeting.

Notwithstanding the preceding paragraph, except as referred to above, any resolution relating to a request, demand, authorization, direction, notice, consent, waiver or other action that may be made, given or taken by the holders of a specified percentage, which is less than a majority of the aggregate principal amount of the outstanding debt securities of a series, may be adopted at a meeting or adjourned meeting duly reconvened at which a quorum is present by the affirmative vote of such specified percentage.

Any resolution passed or decision taken at any properly held meeting of holders of debt securities of any series will be binding on all holders of such series. The quorum at any meeting called to adopt a resolution, and at any reconvened meeting, will be persons holding or representing a majority in principal amount of the outstanding debt securities of a series. However, if any action is to be taken relating to a consent or waiver which may be given by the holders of at least a specified percentage in principal amount of the outstanding debt securities of a series, the persons holding such percentage will constitute a quorum.

Notwithstanding the foregoing provisions, we expect that the indentures will provide that if any action is to be taken at a meeting with respect to any request, demand, authorization, direction, notice, consent, waiver or other action that such indenture expressly provides may be made, given or taken by the holders of a specified percentage in principal amount of all outstanding debt securities affected by such action, or of the holders of such series and one or more additional series:

• there shall be no minimum quorum requirement for such meeting; and

• the principal amount of the outstanding debt securities of such series that vote in favor of such request, demand, authorization, direction, notice, consent, waiver or other action shall be taken account in determining whether such request, demand, authorization, direction, notice, consent, waiver or other action has been made, given or taken under such indenture.

Subordination

Unless otherwise provided in the applicable prospectus supplement and indenture, subordinated securities will be subject to the following subordination provisions.

Upon any distribution to our creditors in a liquidation, dissolution or reorganization, the payment of the principal of and interest on any subordinated securities will be subordinated to the extent provided in the applicable

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indenture in right of payment to the prior payment in full of all senior debt. However, our obligation to make payments of the principal of and interest on such subordinated securities otherwise will not be affected. No payment of principal or interest will be permitted to be made on subordinated securities at any time if a default on senior debt exists that permits the holders of such senior debt to accelerate its maturity and the default is the subject of judicial proceedings or we receive notice of the default. After all senior debt is paid in full and until the subordinated securities are paid in full, holders of subordinated securities will be subrogated to the rights of holders of senior debt to the extent that distributions otherwise payable to holders of subordinated securities have been applied to the payment of senior debt. The subordinated indenture will not restrict the amount of senior debt or other indebtedness of Centessa Therapeutics and its subsidiaries. As a result of these subordination provisions, in the event of a distribution of assets upon insolvency, holders of subordinated securities may recover less, ratably, than our general creditors.

The term “senior debt” will be defined in the applicable indenture as the principal of and interest on, or substantially similar payments to be made by us in respect of, other outstanding indebtedness, whether outstanding at the date of execution of the applicable indenture or subsequently incurred, created or assumed. The prospectus supplement may include a description of additional terms implementing the subordination feature.

No restrictions will be included in any indenture relating to subordinated securities upon the creation of additional senior debt.

If this prospectus is being delivered in connection with the offering of a series of subordinated securities, the accompanying prospectus supplement or the information incorporated in this prospectus by reference will set forth the approximate amount of senior debt outstanding as of the end of our most recent fiscal quarter.

Defeasance and Discharge

The terms of each indenture are expected to provide us with the option to be discharged from any and all obligations in respect of the debt securities issued thereunder upon the deposit with the trustee, in trust, of money or government obligations, or both, which through the payment of interest and principal in accordance with their terms will provide money in an amount sufficient to pay any installment of principal, premium and interest on, and any mandatory sinking fund payments in respect of, the debt securities on the stated maturity of the payments in accordance with the terms of the debt securities and the indenture governing the debt securities. We expect that this right may only be exercised if, among other things, we have received from, or there has been published by, the Internal Revenue Service a ruling to the effect that such a discharge will not be deemed, or result in, a taxable event with respect to holders. This discharge would not apply to our obligations to register the transfer or exchange of debt securities, to replace stolen, lost or mutilated debt securities, to maintain paying agencies and hold moneys for payment in trust.

Defeasance of Certain Covenants

We expect that the terms of the debt securities will provide us with the right not to comply with specified covenants and that specified events of default described in a prospectus supplement will not apply provided we deposit with the trustee money or government obligations, or both, which through the payment of interest and principal will provide money in an amount sufficient to pay any installment of principal, premium, and interest on, and any mandatory sinking fund payments in respect of, the debt securities on the stated maturity of such payments in accordance with the terms of the debt securities and the indenture governing such debt securities. We expect that to exercise this right, we will also be required to deliver to the trustee an opinion of counsel to the effect that the deposit and related covenant defeasance should not cause the holders of such series to recognize income, gain or loss for federal income tax purposes.

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Conversion Rights

The terms and conditions, if any, upon which the debt securities are convertible into ordinary shares will be set forth in the applicable prospectus supplement. The terms will include whether the debt securities are convertible into ordinary shares, the conversion price, or manner of calculation thereof, the conversion period, provisions as to whether conversion will be at the issuing company’s option or the option of the holders, the events requiring an adjustment of the conversion price and provisions affecting conversion in the event of the redemption of the debt securities and any restrictions on conversion.

Global Securities

The debt securities of a series may be issued in whole or in part in the form of one or more global securities that will be deposited with, or on behalf of, a depository identified in the applicable prospectus supplement relating to such series. Global securities, if any, issued in the United States are expected to be deposited with The Depository Trust Company (“DTC”) as depository. We may issue global securities in either registered or bearer form and in either temporary or permanent form. We will describe the specific terms of the depository arrangement with respect to a series of debt securities in the applicable prospectus supplement relating to such series. We expect that unless the applicable prospectus supplement provides otherwise, the following provisions will apply to depository arrangements.

Once a global security is issued, the depository for such global security or its nominee will credit on its book-entry registration and transfer system the respective principal amounts of the individual debt securities represented by such global security to the accounts of participants that have accounts with such depository. Such accounts shall be designated by the underwriters, dealers or agents with respect to such debt securities or by us if we offer such debt securities directly. Ownership of beneficial interests in such global security will be limited to participants with the depository or persons that may hold interests through those participants.

We expect that, under procedures established by DTC, ownership of beneficial interests in any global security for which DTC is the depository will be shown on, and the transfer of that ownership will be effected only through, records maintained by DTC or its nominee, with respect to beneficial interests of participants with the depository, and records of participants, with respect to beneficial interests of persons who hold through participants with the depository. Neither we nor the trustee will have any responsibility or liability for any aspect of the records of DTC or for maintaining, supervising or reviewing any records of DTC or any of its participants relating to beneficial ownership interests in the debt securities. The laws of some states require that certain purchasers of securities take physical delivery of such securities in definitive form. Such limits and laws may impair the ability to own, pledge or transfer beneficial interest in a global security.

So long as the depository for a global security or its nominee is the registered owner of such global security, such depository or such nominee, as the case may be, will be considered the sole owner or holder of the debt securities represented by the global security for all purposes under the applicable indenture. Except as described below or in the applicable prospectus supplement, owners of beneficial interest in a global security will not be entitled to have any of the individual debt securities represented by such global security registered in their names, will not receive or be entitled to receive physical delivery of any such debt securities in definitive form and will not be considered the owners or holders thereof under the applicable indenture. Beneficial owners of debt securities evidenced by a global security will not be considered the owners or holders thereof under the applicable indenture for any purpose, including with respect to the giving of any direction, instructions or approvals to the trustee under the indenture. Accordingly, each person owning a beneficial interest in a global security with respect to which DTC is the depository must rely on the procedures of DTC and, if such person is not a participant with the depository, on the procedures of the participant through which such person owns its interests, to exercise any rights of a holder under the applicable indenture. We understand that, under existing industry practice, if DTC requests any action of holders or if an owner of a beneficial interest in a global security desires to give or take any action which a holder is entitled to give or take under the applicable indenture, DTC would authorize the participants holding the relevant beneficial interest to give or take such action, and such participants

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would authorize beneficial owners through such participants to give or take such actions or would otherwise act upon the instructions of beneficial owners holding through them.

Payments of principal of, and any premium, or make-whole amount, and interest on, individual debt securities represented by a global security registered in the name of a depository or its nominee will be made to or at the direction of the depository or its nominee, as the case may be, as the registered owner of the global security under the applicable indenture. Under the terms of the applicable indenture, we and the trustee may treat the persons in whose name debt securities, including a global security, are registered as the owners thereof for the purpose of receiving such payments. Consequently, neither we nor the trustee have or will have any responsibility or liability for the payment of such amounts to beneficial owners of debt securities including principal, any premium, or make-whole amount, or interest. We believe, however, that it is currently the policy of DTC to immediately credit the accounts of relevant participants with such payments, in amounts proportionate to their respective holdings of beneficial interests in the relevant global security as shown on the records of DTC or its nominee. We also expect that payments by participants to owners of beneficial interests in such global security held through such participants will be governed by standing instructions and customary practices, as is the case with securities held for the account of customers in bearer form or registered in street name, and will be the responsibility of such participants. Redemption notices with respect to any debt securities represented by a global security will be sent to the depository or its nominee. If less than all of the debt securities of any series are to be redeemed, we expect the depository to determine the amount of the interest of each participant in such debt securities to be redeemed to be determined by lot. Neither we, the trustee, any paying agent nor the security registrar for such debt securities will have any responsibility or liability for any aspect of the records relating to or payments made on account of beneficial ownership interests in the global security for such debt securities or for maintaining any records with respect thereto.

Neither we nor the trustee will be liable for any delay by the holders of a global security or the depository in identifying the beneficial owners of debt securities, and we and the trustee may conclusively rely on, and will be protected in relying on, instructions from the holder of a global security or the depository for all purposes. The rules applicable to DTC and its participants are on file with the SEC.

If a depository for any debt securities is at any time unwilling, unable or ineligible to continue as depository and we do not appoint a successor depository within 90 days, we will issue individual debt securities in exchange for the global security representing such debt securities. In addition, we may at any time and in our sole discretion, subject to any limitations described in the applicable prospectus supplement relating to such debt securities, determine not to have any of such debt securities represented by one or more global securities and in such event will issue individual debt securities in exchange for the global security or securities representing such debt securities. Individual debt securities so issued will be issued in denominations of $1,000 and integral multiples of $1,000.

The debt securities of a series may also be issued in whole or in part in the form of one or more bearer global securities that will be deposited with a depository, or with a nominee for such depository, identified in the applicable prospectus supplement. Any such bearer global securities may be issued in temporary or permanent form. The specific terms and procedures, including the specific terms of the depositary arrangement, with respect to any portion of a series of debt securities to be represented by one or more bearer global securities will be described in the applicable prospectus supplement.

No Recourse

There is no recourse under any obligation, covenant or agreement in the applicable indenture or with respect to any security against any of our or our successor’s past, present or future shareholders, employees, officers or directors.

We refer you to any applicable prospectus supplement with respect to any deletions or additions or modifications to the descriptions above.

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DESCRIPTION OF WARRANTS

We may offer warrants for the purchase of ordinary shares, each of which may be represented by one American Depositary Share, and/or senior or subordinated debt securities in one or more series, from time to time. We may issue warrants independently or together with ordinary shares, each of which may be represented by one American Depositary Share, and/or senior or subordinated debt securities, and the warrants may be attached to or separate from those securities.

If we offer warrants, they will be evidenced by warrant certificates issued under one or more warrant agreements, which are contracts between us and an agent for the holders of the warrants. We will indicate the name and address of the warrant agent in the applicable prospectus supplement relating to a particular series of warrants.

The prospectus supplement for each offering will provide the following terms, where applicable:

• the offering price and aggregate number of warrants offered;

• the currency for which the warrants may be purchased;

• if applicable, the designation and terms of the securities with which the warrants are issued and the number of warrants issued with each such security or each principal amount of such security;

• if applicable, the date on and after which the warrants and the related securities will be separately transferable;

• in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one warrant and the price at, and currency in which, this principal amount of debt securities may be purchased upon such exercise;

• in the case of warrants to purchase securities, the number of shares purchasable upon the exercise of one warrant and the price at which these shares may be purchased upon such exercise;

• the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreement and the warrants;

• the terms of any rights to redeem or call the warrants;

• any provisions for changes to or adjustments in the exercise price or number of securities issuable upon exercise of the warrants;

• the periods during which, and places at which, the warrants are exercisable;

• the manner of exercise;

• the dates on which the right to exercise the warrants will commence and expire;

• the manner in which the warrant agreement and warrants may be modified;

• United States federal income tax consequences of holding or exercising the warrants;

• the terms of the securities issuable upon exercise of the warrants; and

• any other specific terms, preferences, rights or limitations of or restrictions on the warrants.

We urge you to read the prospectus supplement related to any series of warrants we may offer, as well as the complete warrant agreement and warrant certificate that contain the terms of the warrants. If we offer warrants, forms of warrant agreements and warrant certificates relating to warrants for the purchase of such ordinary shares and debt securities will be incorporated by reference into the registration statement of which this prospectus is a part from reports we would subsequently file with the SEC.

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DESCRIPTION OF UNITS

We may offer units consisting of ordinary shares, ordinary shares in the form of ADSs, debt securities and/or warrants for the purchase of ordinary shares and/or debt securities in any combination in one or more series, from time to time.

If we offer units, they will be evidenced by unit certificates issued under one or more unit agreements, which are contracts between us and an agent for the holders of the units.

If we offer any units, certain terms of that series of units will be described in the applicable prospectus supplement, including, without limitation, the following, as applicable:

• the title of the series of units;

• identification and description of the separate constituent securities comprising the units;

• the price or prices at which the units will be issued;

• the date, if any, on and after which the constituent securities comprising the units will be separately transferable;

• a discussion of certain United States federal income tax considerations applicable to the units; and

• any other terms of the units and their constituent securities.

We urge you to read the prospectus supplement related to any series of units we may offer, as well as the complete unit agreement and unit certificate that contain the terms of the unit. If we offer units, forms of unit agreements and unit certificates relating to units will be incorporated by reference into the registration statement of which this prospectus is a part from reports we would subsequently file with the SEC.

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TAXATION

U.S. Federal Income Tax Considerations For U.S. Holders

The applicable prospectus supplement will contain information about any material U.S. federal income tax considerations relating to the securities covered by such prospectus supplement.

U.K. Taxation

The applicable prospectus supplement will contain information about any U.K. tax considerations relating to the securities covered by such prospectus supplement.

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USE OF PROCEEDS

We will retain broad discretion over the use of the net proceeds from the sale of our securities offered by us under this prospectus. Except as described in any prospectus supplement, we currently anticipate using the net proceeds from the sale of our securities offered hereby primarily for general corporate purposes. We may also use a portion of the net proceeds to pay interest or principal on outstanding indebtedness, if any, and/or acquire or invest in complementary businesses, products and technologies. Although we have no specific agreements, commitments or understandings with respect to any acquisition, we evaluate acquisition opportunities and engage in related discussions with other companies from time to time.

Pending the use of the net proceeds, we intend to invest the net proceeds in in a variety of capital preservation instruments, including short-term, interest-bearing, investment-grade securities.

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PLAN OF DISTRIBUTION

We may sell our securities from time to time in one or more transactions. We may sell our securities to or through agents, underwriters, dealers, remarketing firms or other third parties or directly to one or more purchasers or through a combination of any of these methods. In some cases, we or dealers acting with us or on our behalf may also purchase our securities and reoffer them to the public. We may also offer and sell, or agree to deliver, securities pursuant to, or in connection with, any option agreement or other contractual arrangement.

Agents whom we designate may solicit offers to purchase our securities.

• We will name any agent involved in offering or selling our securities, and disclose any commissions that we will pay to the agent, in the applicable prospectus supplement.

• Unless indicate otherwise in the applicable prospectus supplement, agents will act on a best efforts basis for the period of their appointment.

• Agents may be deemed to be underwriters under the Securities Act of any of our securities that they offer or sell.

We may use an underwriter or underwriters in the offer or sale of our securities.

• If we use an underwriter or underwriters, we will execute an underwriting agreement with the underwriter or underwriters at the time that we reach an agreement for the sale of our securities.

• We will include the names of the specific managing underwriter or underwriters, as well as the names of any other underwriters, and the terms of the transactions, including the compensation the underwriters and dealers will receive, in the applicable prospectus supplement.

• The underwriters will use the applicable prospectus supplement, together with the prospectus, to sell our securities.

We may use a dealer to sell our securities.

• If we use a dealer, we will sell our securities to the dealer, as principal.

• The dealer will then sell our securities to the public at varying prices that the dealer will determine at the time it sells our securities.

• We will include the name of the dealer and the terms of the transactions with the dealer in the applicable prospectus supplement.

One or more firms, referred to as “remarketing firms,” may also offer or sell the securities, if a prospectus supplement so indicates, in connection with a remarketing arrangement upon their purchase. Remarketing firms will act as principals for their own accounts or as our agents. These remarketing firms will offer or sell the securities in accordance with the terms of the securities. Each prospectus supplement will identify and describe any remarketing firm and the terms of its agreement, if any, with us and will describe the remarketing firm’s compensation. Remarketing firms may be deemed to be underwriters in connection with the securities they remarket. Remarketing firms may be entitled under agreements that may be entered into with us to indemnification by us against certain civil liabilities, including liabilities under the Securities Act, and may be customers of, engage in transactions with or perform services for us in the ordinary course of business.

We may solicit directly offers to purchase our securities, and we may directly sell our securities to institutional or other investors. We will describe the terms of direct sales in the applicable prospectus supplement.

We may engage in at the market offerings into an existing trading market in accordance with Rule 415(a)(4) of the Securities Act.

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We may enter into derivative or hedging transactions with third parties or sell securities not covered by this prospectus to third parties in privately negotiated transactions. In connection with such a transaction, the third parties may sell securities covered by and pursuant to this prospectus and any accompanying prospectus supplement. If so, the third party may use securities borrowed from us or others to settle such sales and may use securities received from us to close out any related short positions. We may also loan or pledge securities covered by this prospectus and any accompanying prospectus supplement to third parties, who may sell the loaned securities or, in an event of default in the case of a pledge, sell the pledged securities pursuant to this prospectus and any accompanying prospectus supplement.

Agents, underwriters and dealers participating in the distribution of the securities may be deemed to be underwriters within the meaning of the Securities Act, and any discounts and commissions received by them and any profit realized by them on resale of the securities may be deemed to be underwriting discounts and commissions. In addition, the underwriters’ commissions, discounts or concessions may qualify as underwriters’ compensation under the Securities Act and the rules of the Financial Industry Regulatory Authority, Inc. We may indemnify agents, underwriters and dealers against certain liabilities, including liabilities under the Securities Act. Agents, underwriters and dealers, or their affiliates, may be customers of, engage in transactions with or perform services for us or our respective affiliates, in the ordinary course of business.

We may authorize agents and underwriters to solicit offers by certain institutions to purchase our securities at the public offering price under delayed delivery contracts.

• If we use delayed delivery contracts, we will disclose that we are using them in the prospectus supplement and will tell you when we will demand payment and when delivery of our securities will be made under the delayed delivery contracts.

• These delayed delivery contracts will be subject only to the conditions that we describe in the prospectus supplement.

• We will describe in the applicable prospectus supplement the commission that underwriters and agents soliciting purchases of our securities under delayed delivery contracts will be entitled to receive.

Unless otherwise specified in connection with a particular underwritten offering of our securities, the underwriters will not be obligated to purchase offered securities unless specified conditions are satisfied, and if the underwriters do purchase any offered securities, they will purchase all offered securities.

Certain underwriters may use this prospectus and any accompanying prospectus supplement for offers and sales related to market-making transactions in the securities. These underwriters may act as principal or agent in these transactions, and the sales will be made at prices related to prevailing market prices at the time of sale.

In order to facilitate the offering of the securities, certain persons participating in the offering may engage in transactions that stabilize, maintain or otherwise affect the price of the securities. This may include over-allotments or short sales of the securities, which involve the sale by persons participating in the offering of more securities than we sold to them. In these circumstances, these persons would cover such over-allotments or short positions by making purchases in the open market or by exercising their over-allotment option. In addition, these persons may stabilize or maintain the price of the securities by bidding for or purchasing the applicable security in the open market or by imposing penalty bids, whereby selling concessions allowed to dealers participating in the offering may be reclaimed if the securities sold by them are repurchased in connection with stabilization transactions. The effect of these transactions may be to stabilize or maintain the market price of the securities at a level above that which might otherwise prevail in the open market. These transactions may be discontinued at any time.

The underwriters, dealers and agents may engage in other transactions with us, or perform other services for us, in the ordinary course of their business.

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We may effect sales of securities in connection with forward sale, option, swap or other types of agreements with third parties.

Any distribution of securities pursuant to any sale may be effected from time to time in one or more transactions that may take place through a stock exchange, including block trades or ordinary broker’s transactions, or through broker-dealers acting either as principal or agent, or through privately-negotiated transactions, or through an underwritten public offering, or through a combination of any such methods of sale, at market prices prevailing at the time of sale, prices relating to such prevailing market prices or at negotiated or fixed prices.

The specific terms of the lock-up provisions, if any, with respect to any given offering will be described in the applicable prospectus supplement.

The expenses of any offering of our securities will be detailed in the applicable prospectus supplement.

We will identify the specific plan of distribution, including any agents, underwriters, dealers, remarketing firms or other third parties and their compensation in a prospectus supplement.

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LEGAL MATTERS

Certain legal matters of English law and U.S. federal law will be passed upon for us by Goodwin Procter (UK) LLP and Goodwin Procter LLP, respectively. Any underwriters will be advised about other issues relating to any offering by their own legal counsel.

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EXPERTS

The consolidated financial statements of Centessa Pharmaceuticals plc and subsidiaries as of December 31, 2023 and 2022, and for the years then ended, have been incorporated by reference herein in reliance upon the report of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing.

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SERVICE OF PROCESS AND ENFORCEMENT OF LIABILITIES

We are incorporated and currently existing under the laws of England and Wales. In addition, certain of our directors and officers reside outside of the United States and most of the assets of our non-U.S. subsidiaries are located outside of the United States. As a result, it may be difficult for investors to effect service of process on us or those persons in the United States or to enforce in the United States judgments obtained in United States courts against us or those persons based on the civil liability or other provisions of the United States securities laws or other laws. In addition, uncertainty exists as to whether the courts of England and Wales would:

• recognize or enforce judgments of United States courts obtained against us or our directors or officers predicated upon the civil liabilities provisions of the securities laws of the United States or any state in the United States; or

• entertain original actions brought in England and Wales against us or our directors or officers predicated upon the securities laws of the United States or any state in the United States.

There is currently no treaty between (i) the United States and (ii) England and Wales providing for reciprocal recognition and enforcement of judgments of United States courts in civil and commercial matters (although the United States and the United Kingdom are both parties to the New York Convention on the Recognition and Enforcement of Foreign Arbitral Awards) and that a final judgment for the payment of money rendered by any general or state court in the United States based on civil liability, whether predicated solely upon the United States securities laws, would not be automatically enforceable in England and Wales. Any final and conclusive monetary judgment for a definite sum obtained against us in United States courts would be treated by the courts of England and Wales as a cause of action in itself and sued upon as a debt at common law so that no retrial of the issues would be necessary, provided that:

• the relevant U.S. court had jurisdiction over the original proceedings according to English conflicts of laws principles at the time when proceedings were initiated;

• England and Wales courts had jurisdiction over the matter on enforcement and we either submitted to such jurisdiction or were resident or carrying on business within such jurisdiction and were duly served with process;

• the U.S. judgment was final and conclusive on the merits in the sense of being final and unalterable in the court that pronounced it and being for a definite sum of money;

• the judgment given by the courts was not in respect of penalties, taxes, fines or similar fiscal or revenue obligations (or otherwise based on a U.S. law that an English court considers to relate to a penal, revenue or other public law);

• the judgment was not procured by fraud;

• recognition or enforcement of the judgment in England and Wales would not be contrary to public policy or the Human Rights Act 1998;

• the proceedings pursuant to which judgment was obtained were not contrary to natural justice;

• the U.S. judgment was not arrived at by doubling, trebling or otherwise multiplying a sum assessed as compensation for the loss or damages sustained and not being otherwise in breach of Section 5 of the UK Protection of Trading Interests Act 1980, or is a judgment based on measures designated by the Secretary of State under Section 1 of that Act;

• there is not a prior decision of an English court or the court of another jurisdiction on the issues in question between the same parties; and

• the English enforcement proceedings were commenced within the limitation period.

Whether these requirements are met in respect of a judgment based upon the civil liability provisions of the United States securities laws, including whether the award of monetary damages under such laws would constitute a penalty, is an issue for the court making such decision.

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Subject to the foregoing, investors may be able to enforce in England and Wales judgments in civil and commercial matters that have been obtained from U.S. federal or state courts. Nevertheless, we cannot assure you that those judgments will be recognized or enforceable in England and Wales.

If an English court gives judgment for the sum payable under a U.S. judgment, the English judgment will be enforceable by methods generally available for this purpose. These methods generally permit the English court discretion to prescribe the manner of enforcement. In addition, it may not be possible to obtain an English judgment or to enforce that judgment if the judgment debtor is or becomes subject to any insolvency or similar proceedings, or if the judgment debtor has any set-off or counterclaim against the judgment creditor. Also note that, in any enforcement proceedings, in certain circumstances the judgment debtor may raise any counterclaim that could have been brought if the action had been originally brought in England unless the subject of the counterclaim was in issue and denied (other than on procedural grounds) in the U.S. proceedings.

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WHERE YOU CAN FIND MORE INFORMATION

This prospectus is part of a registration statement on Form S-3 we filed with the SEC under the Securities Act and does not contain all the information set forth or incorporated by reference in the registration statement. Whenever a reference is made in this prospectus to any of our contracts, agreements or other documents, the reference may not be complete and you should refer to the exhibits that are a part of the registration statement or the exhibits to the reports or other documents incorporated by reference into this prospectus for a copy of such contract, agreement or other document. You may obtain copies of the registration statement and its exhibits via the SEC’s EDGAR database.

We file annual, quarterly and current reports, proxy statements and other information with the SEC under the Exchange Act. The SEC maintains a website that contains reports, proxy and information statements and other information regarding issuers, including us, that file electronically with the SEC. You may obtain documents that we file with the SEC at www.sec.gov.

Our website address is http://www.centessa.com. We do not incorporate the information on or accessible through our website into this prospectus or any prospectus supplement, and you should not consider any information on, or that can be accessed through, our website as part of this prospectus or any prospectus supplement. Our website address is included in this prospectus as an inactive textual reference only.

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INCORPORATION BY REFERENCE

The SEC allows us to incorporate by reference into this prospectus the information contained in other documents we file with the SEC, which means that we can disclose important information to you by referring you to those documents. Any statement contained in any document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded, for purposes of this prospectus, to the extent that a statement contained in or omitted from this prospectus, or in any other subsequently filed document that also is or is deemed to be incorporated by reference herein, modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus. We incorporate by reference the documents listed below which have been filed by us:

• Our Annual Report on  Form 10-K for the year ended December 31, 2023, filed with the SEC on March 28, 2024

• Quarterly Reports on Form 10-Q for the quarter ended March 31, 2024, filed with the SEC on May 13, 2024 and for the quarter ended June 30, 2024, filed with the SEC on August 13, 2024;

• Current Reports on Form 8-K filed with the SEC on  April 22, 2024, April 24, 2024, June  10, 2024, June  25, 2024 and September 10, 2024 (except that, with respect to the foregoing Current Reports, any portions thereof which are furnished and not filed shall not be deemed incorporated by reference);

• Our definitive proxy statement on Schedule 14A filed with the SEC on May 9, 2024 and amended on May 21, 2024; and

• The description of our ordinary shares and ADSs contained in our Registration Statement on  Form 8-A, as filed with the SEC under Section 12(b) of the Exchange Act on May 25, 2021, including any amendment or report filed for the purpose of updating such description (File No. 001-40445).

All reports and other documents we subsequently file pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act on or after the date of this prospectus, until the earlier of the date on which all of the securities registered hereunder have been sold or the registration statement of which this prospectus is a part has been withdrawn, but excluding any information furnished to, rather than filed with, the SEC, will also be incorporated by reference into this prospectus and deemed to be part of this prospectus from the date of the filing of such reports and documents.

We will provide to each person at their request, including any beneficial owner, to whom a prospectus is delivered, a copy of any or all of the reports or documents that have been incorporated by reference into this prospectus but not delivered with this prospectus free of charge. We will provide these reports upon written or oral request at no cost to the requester. Please direct your request, either in writing or by telephone, to the following address and telephone number:

Centessa Pharmaceuticals plc

3rd Floor, 1 Ashley Rd,

Altrincham, Cheshire,

United Kingdom, WA14 2DT

+1 (617) 468-5770

You may also access these documents on our website, http://www.centessa.com. The information contained on, or that can be accessed through, our website is not a part of this prospectus. We have included our website address in this prospectus solely as an inactive textual reference.

You should rely only on the information incorporated by reference or provided in this prospectus. We have not authorized anyone else to provide you with different or additional information. An offer of these securities is not being made in any jurisdiction where the offer or sale is not permitted. You should not assume that the information in this prospectus is accurate as of any date other than the date on the front of those documents.

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$150,000,000

Centessa Pharmaceuticals plc

American Depositary Shares Representing Ordinary Shares

PRELIMINARY PROSPECTUS SUPPLEMENT

Goldman Sachs & Co. LLC

Leerink Partners

Evercore ISI

Guggenheim Securities

BMO Capital Markets

    , 2024