Mural Oncology (MURA) 10-Q 14 May 24 2024 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2024	May 01, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	001-41837
Entity Registrant Name	Mural Oncology plc
Entity Central Index Key	0001971543
Entity Incorporation, State or Country Code	L2
Entity Tax Identification Number	98-1748617
Entity Address, Address Line One	10 Earlsfort Terrace
Entity Address, City or Town	Dublin 2
Entity Address, Country	IE
Entity Address, Postal Zip Code	D02 T380
City Area Code	353
Local Phone Number	1-905-8020
Title of 12(b) Security	Ordinary shares, nominal value $0.01 per share
Trading Symbol	MURA
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		16,923,878

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
CURRENT ASSETS:
Cash and cash equivalents	$ 107,263	$ 270,852
Marketable securities	124,411	0
Receivable from former parent	1,895	5,548
Prepaid expenses	5,239	150
Other current assets	620	787
Total current assets	239,428	277,337
Property and equipment, net	10,612	11,403
Right-of-use assets	11,418	12,747
Restricted cash	1,969	258
Other assets	77	0
TOTAL ASSETS	263,504	301,745
CURRENT LIABILITIES:
Accounts payable	1,567	5,973
Accrued expenses	13,524	16,946
Operating lease liabilities-short-term	6,156	6,098
Total current liabilities	21,247	29,017
Operating lease liabilities-long-term	7,330	8,911
Total liabilities	28,577	37,928
Commitments and contingencies (Note 10)
Preferred shares, nominal value $0.01; 50,000,000 shares authorized at March 31, 2024; no shares issued or outstanding at March 31, 2024 or December 31, 2023	0	0
Ordinary shares, nominal value $0.01; 450,000,000 ordinary shares authorized at March 31, 2024 and December 31, 2023; 16,922,550 and 16,689,740 shares issued and outstanding at March 31, 2024 and December 31, 2023, respectively	169	167
Additional paid-in capital	296,606	294,507
Unrealized loss on marketable securities	(74)	0
Accumulated deficit	(61,774)	(30,857)
Total equity	234,927	263,817
TOTAL LIABILITIES AND EQUITY	$ 263,504	$ 301,745

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred shares, par value	$ 0.01	$ 0.01
Preferred shares, shares authorized	50,000,000	50,000,000
Preferred shares, shares issued	0	0
Preferred shares, shares outstanding	0	0
Ordinary shares, par value	$ 0.01	$ 0.01
Ordinary shares, shares authorized	450,000,000	450,000,000
Ordinary shares, shares issued	16,922,550	16,689,740
Ordinary shares, shares outstanding	16,922,550	16,689,740

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating expenses
Research and development	$ 26,868	$ 40,410
General and administrative	7,165	3,746
Total operating expenses	34,033	44,156
Operating loss	(34,033)	(44,156)
Other income	3,116
Income tax provision	0	(2,311)
Net loss	(30,917)	(46,467)
Other comprehensive loss:
Unrealized loss on marketable securities	(74)
Other comprehensive loss	(74)
Comprehensive loss	$ (30,991)	$ (46,467)
Net loss per ordinary share - basic	$ (1.84)	$ (2.78)
Net loss per ordinary share - diluted	$ (1.84)	$ (2.78)
Weighted average ordinary shares outstanding - basic	16,793,657	16,689,740
Weighted average ordinary shares outstanding - diluted	16,793,657	16,689,740

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Equity (Deficit) - USD ($) $ in Thousands	Total	Ordinary Shares	Additional Paid in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Net Parent Investment
Beginning balance at Dec. 31, 2022	$ (21,656)					$ (21,656)
Beginning balance, in shares at Dec. 31, 2022		0
Net transfers from Former Parent prior to Separation	56,135					56,135
Share-based compensation expense allocated from Former Parent	2,753					2,753
Net Income (Loss)	(46,467)					(46,467)
Ending balance at Mar. 31, 2023	(9,235)					$ (9,235)
Ending balance, in shares at Mar. 31, 2023		0
Beginning balance at Dec. 31, 2023	263,817	$ 167	$ 294,507		$ (30,857)
Beginning balance, in shares at Dec. 31, 2023		16,689,740
Issuance of ordinary shares under employee share plans		$ 2	(2)
Issuance of ordinary shares under employee share plans, shares		232,810
Share-based compensation expense	2,101		2,101
Unrealized loss on marketable securities	(74)			$ (74)
Net Income (Loss)	(30,917)				(30,917)
Ending balance at Mar. 31, 2024	$ 234,927	$ 169	$ 296,606	$ (74)	$ (61,774)
Ending balance, in shares at Mar. 31, 2024		16,922,550

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (30,917)	$ (46,467)
Adjustments to reconcile net loss to cash flows from operating activities:
Depreciation	846	530
Share-based compensation expense	2,199	2,753
Changes in assets and liabilities:
Receivable from Former Parent	3,653
Prepaid expenses	(5,089)	1,024
Other current assets	167	(582)
Right-of-use assets	1,329	3,066
Other assets	(77)
Accounts payable and accrued expenses	(7,926)	(14,664)
Operating lease liabilities	(1,523)	(1,460)
Other long-term liabilities		63
Cash flows used in operating activities	(37,338)	(55,737)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities	(124,485)
Additions of property and equipment	(55)	(398)
Cash flows used in investing activities	(124,540)	(398)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net transfers from Former parent		56,135
Cash flows provided by financing activities		56,135
Net decrease in cash, cash equivalents and restricted cash	(161,878)
Cash, cash equivalents and restricted cash-beginning of period	271,110
Cash, cash equivalents and restricted cash-end of period	109,232
Non-cash investing and financing activities:
Purchased capital expenditures included in accounts payable and accrued expenses		$ 75
Reconciliation Of Balance Sheet To Statement Of Cash Flows Abstract
Cash and cash equivalents	107,263		$ 270,852
Restricted cash	1,969		300
Total cash, cash equivalents and restricted cash as shown in the statement of cash flows	$ 109,232		$ 271,110

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (30,917)	$ (46,467)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	During the first quarter of 2024, Adam Cutler , our Chief Financial Officer , and Caroline Loew , our Chief Executive Officer , each entered into a Rule 10b5-1 trading arrangement that is intended to qualify as an “eligible sell-to-cover transaction” (as described in Rule 10b5-1(c)(1)(ii)(D)(3) under the Exchange Act). These sell-to-cover arrangements, which were adopted on January 12, 2024 and March 27, 2024 , respectively, apply to restricted stock units (“RSUs”), whether vesting is based on the passage of time and/or the achievement of performance goals, granted on December 14, 2023 and March 1, 2024, and any RSUs that may be granted from time to time thereafter (other than those which by their terms require us to withhold shares for tax withholding obligations in connection with vesting and settlement). These arrangements provide for the automatic sale of ordinary shares that would otherwise be issuable on each settlement date of a covered RSU in an amount necessary to satisfy the applicable withholding obligation, with the proceeds of the sale delivered to us in satisfaction of the applicable withholding obligation. The number of ordinary shares that will be sold under these arrangements is not currently determinable as the number will vary based on the extent to which vesting conditions are satisfied, the market price of our ordinary shares at the time of settlement and the potential future grant of additional RSUs subject to this arrangement. None of our directors or officers terminated a Rule 10b5-1 trading arrangement or adopted or terminated a non-Rule 10b5-1 trading arrangement (as defined in Item 408(c) of Regulation S-K) during the first quarter of 2024.
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Adam Cutler
Trading Arrangements, by Individual
Name	Adam Cutler
Title	Chief Financial Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	January 12, 2024
Caroline Loew
Trading Arrangements, by Individual
Name	Caroline Loew
Title	Chief Executive Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 27, 2024

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. Organization and Description of Business Mural Oncology plc and its consolidated subsidiaries (“Mural” or the “Company”), an Irish public limited company, is a clinical-stage oncology business focused on discovering and developing immunotherapies that may meaningfully improve the lives of patients with cancer. By leveraging its core competencies in immune cell modulation and protein engineering, the Company has developed a portfolio of investigational cytokine therapies designed to address areas of unmet need for patients with a variety of cancers. The Company was established as a shelf company in May 2017 as a private company limited by shares and was de-shelved in 2023 in connection with the Separation. In August 2023, the legal status of the Company under Irish law was altered to that of a public limited company. The accompanying financial statements include the combined, historical financial position, results of operations, net parent investment and cash flows of Alkermes plc, an Irish public limited company, and its consolidated subsidiaries’ (the “Former Parent” or “Alkermes”) oncology business (the “oncology business”) as it was historically managed as part of the Former Parent prior to the completion of the separation of the Former Parent’s oncology business from the Former Parent’s neuroscience business on November 15, 2023 (the “Separation”), and the creation of the Company, as a result of the Distribution (as defined below), as an independent, publicly traded company, which holds the assets, liabilities, and operations associated with the oncology business. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry. There can be no assurance that the Company’s research and development (“R&D”) will be successfully completed, that any products developed will obtain necessary government regulatory approval or that any products, if approved, will be commercially viable. The Company operates in an environment of rapid technological innovation and substantial competition from pharmaceutical and biotechnological companies. In addition, the Company is dependent upon the services of its employees, consultants and service providers. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant product revenue from product sales. The Separation On November 2, 2022, the Former Parent announced its intent, as approved by its board of directors, to explore the Separation. In connection with the Separation, on November 13, 2023, the Company entered into certain agreements with the Former Parent to provide a framework for the Company’s relationship with the Former Parent following the Separation. These agreements include: • a separation agreement; • a tax matters agreement; • an employee matters agreement; • a lease assumption agreement; and • transition services agreements. The separation agreement sets forth the Company’s agreements with the Former Parent regarding the principal actions to be taken by the Company and the Former Parent in connection with the Separation, including those related to the distribution of the Company’s ordinary shares to the Former Parent’s shareholders (the “Distribution”). The separation agreement identifies the assets transferred to, liabilities assumed by and contracts assigned to the Company, including the Winter Street Lease (as defined in Note 7, Leases ), as part of the Separation, and provides for when and how such transfers, assumptions and assignments occurred. Under the terms of the separation agreement, the Former Parent granted the Company a perpetual, worldwide, non-exclusive, royalty-free, fully paid-up license (or, as the case may be, sublicense) to any intellectual property controlled by the Former Parent as of the date of the Distribution, allowing the Company to use such intellectual property for the oncology business, and the Company granted the Former Parent a perpetual, worldwide, non-exclusive, royalty-free, fully paid-up license (or, as the case may be, sublicense) to intellectual property transferred to the Company as part of the Separation for the Former Parent’s use outside of the oncology business. Each of the Company and the Former Parent agreed to releases with respect to pre-Distribution claims, and cross-indemnities with respect to post-Distribution claims, that are principally designed to place financial responsibility for the obligations and liabilities allocated to the Company under the separation agreement with the Company, and financial responsibility for the obligations and liabilities allocated to the Former Parent under the separation agreement with the Former Parent. The Company and the Former Parent are also each subject to mutual six-month employee non-solicitation and non-hire restrictions, subject to certain customary exceptions, and certain confidentiality restrictions and information sharing obligations. The tax matters agreement governs the Company’s and the Former Parent’s respective rights, responsibilities, and obligations with respect to taxes (including taxes arising in the ordinary course of business and incurred as a result of any failure of the Distribution, together with certain related transactions, to qualify as tax-free for U.S. federal income tax purposes), tax attributes, the preparation and filing of tax returns, the control of audits and other tax proceedings, and assistance and cooperation in respect to tax matters. The employment matters agreement, as amended in December 2023, governs the Company’s and the Former Parent’s rights, responsibilities, and obligations after the Separation with respect to employment, benefits and compensation matters relating to employees and former employees (and their respective dependents and beneficiaries) who are or were associated with the Former Parent, including those who became employees of the Company in connection with the Separation. The employee matters agreement also specifies the allocation of assets and liabilities generally relating to employees, employment or service-related matters and employee benefit plans; other human resources, employment and employee benefits matters; and the treatment of equity-based awards granted by the Former Parent prior to the Separation to employees who became employees of the Company in connection with the Separation. Under the terms of the lease assumption agreement, the Company assumed all of the Former Parent’s obligations under the Winter Street Lease. The Company and the Former Parent entered into two transition services agreements, pursuant to one of which the Former Parent and its subsidiaries agreed to provide, on an interim, transitional basis, various services to the Company, and the second of which the Company and its subsidiaries agreed to provide certain services to the Former Parent, in each case for a term of two years following the Separation, unless earlier terminated in accordance with the terms of the applicable agreement. On November 14, 2023, in connection with the Separation, the Company received a cash contribution of $ 275.0 million from the Former Parent. The Former Parent effected the Separation through the Distribution on November 15, 2023 . On the effective date of the Distribution, each Alkermes shareholder received one ordinary share of the Company for every ten ordinary shares of Alkermes held as of the close of business on November 6, 2023, the record date for the Distribution. Registered shareholders received cash in lieu of any fractional ordinary shares of the Company that they would have received as a result of the application of the distribution ratio. As a result of the Separation and the Distribution, the Company operates as an independent, publicly traded company and commenced trading under the symbol “MURA” on the Nasdaq Global Market on November 16, 2023. Liquidity Under Accounting Standards Update ("ASU") No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40), the Company has the responsibility to evaluate whether conditions and/or events raise substantial doubt about its ability to meet its future financial obligations as they become due within one year after the date that the financial statements are issued. The Company has generated operating losses for all the historical periods presented and expects to continue to generate operating losses for the foreseeable future. The Company expects to fund its operations and capital needs through the funding received from the Former Parent through the date of the Separation, including the cash contribution of $ 275.0 million received from the Former Parent at the time of the Separation. The Company’s continued operations were dependent on the funding received from the Former Parent through the Separation and, going forward, will be dependent on its ability to generate cash from operating activities and to raise additional capital to finance its future operations subsequent to the Separation. The Company will need additional financing to support its continuing operations and further develop or commercialize any product candidates. If the Company is unable to obtain additional funding on a timely basis, it may be forced to significantly curtail, delay, or discontinue one or more of the planned research or development programs or be unable to expand or continue operations. There is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all. For the four-year period beginning two years before and ending two years after the Distribution, the Company is prohibited under the tax matters agreement with the Former Parent from taking or failing to take actions that would prevent the Separation and the Distribution, in relevant part and together with certain related transactions, from qualifying as transactions that are tax-free for U.S. federal income tax purposes under Sections 355 and 368(a)(1)(D) of the Internal Revenue Code of 1986, as amended (the “Code”), which may limit for a period of time the Company’s ability to pursue certain strategic transactions, equity issuances or repurchases or other transactions. The Company expects that, based on its current operating plans, the Company’s existing cash and cash equivalents will be sufficient to fund its current planned operations for at least the next twelve months from the issuance of these unaudited condensed consolidated financial statements.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	2. Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of Mural Oncology plc and its wholly-owned subsidiaries. For the periods prior to the Separation, the accompanying unaudited condensed consolidated financial statements of the Company have been prepared on a standalone basis and are derived from the Former Parent’s consolidated financial statements and accounting records. All intercompany transactions and accounts within the Company have been eliminated. The unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and, for the periods prior to the Separation, reflect the historical results of operations, financial position and cash flows of Mural, as included in the consolidated financial statements of the Former Parent and using the Former Parent’s historical accounting policies. For the periods prior to the Separation, these unaudited condensed consolidated financial statements do not purport to reflect what the Company’s results of operations, financial position or cash flows would have been had the Company operated as a standalone public company prior to the Separation, nor are they necessarily indicative of the Company’s future results of operations, financial position, or cash flows. As the Company’s operations were not historically held by a single legal entity or separate legal entities, net parent investment is shown in lieu of stockholders’ equity in the historical combined financial statements for the periods prior to the Separation. Net parent investment represents the cumulative investment by the Former Parent in the Company through the dates presented, inclusive of operating results. All transactions between the Company and the Former Parent are considered to be effectively settled in the unaudited condensed consolidated financial statements at the time the transaction is recorded. The effects of the settlement of these transactions between the Company and the Former Parent are reflected in the unaudited condensed consolidated statements of cash flows as “Net transfers from Former Parent” within financing activities and in the unaudited condensed consolidated statements of equity (deficit) as “Net parent investment.” Historically, the Company was dependent upon the Former Parent for all of its working capital and financing requirements, as the Former Parent used a centralized approach to cash management and financing its operations. There were no cash amounts specifically attributable to the Company for the historical periods presented prior to the Separation. Financing transactions prior to the Separation related to the Former Parent are accounted for as a financing activity on the accompanying unaudited condensed consolidated statements of cash flows through the date of the Separation. In connection with the Separation, certain assets and liabilities that were included on the consolidated balance sheet prior to the Separation were retained by the Former Parent and were therefore adjusted through net parent investment in the Company’s consolidated financial statements. The unaudited condensed consolidated financial statements of the Company include, for the periods prior to the Separation, the assets, liabilities, and expenses of the Former Parent that management has determined are specifically identifiable to the Company, such as those related to direct internal and external R&D activities as well as leases and fixed assets specifically identifiable to the oncology business. Based on the nature of the Company as a pre-revenue, development-stage biotechnology company, the unaudited condensed consolidated financial statements of the Company do not include any revenue or commercial expenses of the Former Parent. The unaudited condensed consolidated financial statements of the Company also include, for the periods prior to the Separation, an allocation of costs that were not directly attributable to the operations of the Company, including the costs of general and administrative support functions that were provided by the Former Parent, such as senior management, information technology, legal, accounting and finance, human resources, facility, and other corporate services. In addition, the Company’s unaudited condensed consolidated financial statements include, for the periods prior to the Separation, an allocation of certain R&D costs not directly attributable to individual programs. These costs have been allocated to the Company for the purposes of preparing the unaudited condensed consolidated financial statements based on proportional cost allocation methods using headcount, square footage or proportional hours worked supporting the Company and other organizational activities, as applicable, which are considered to be reasonable reflections of the utilization of services provided or benefit received by the Company during the periods presented. Management considers that such allocations have been made on a reasonable basis; however, these allocations may not necessarily be indicative of the costs that would have been incurred if the Company had operated on a standalone basis for the periods presented and, therefore, may not reflect the Company’s results of operations, financial position, and cash flows had the Company operated as a standalone entity during the periods presented. See Note 12, Related Parties , for additional information regarding related-party transactions with the Former Parent. The Company expects to incur additional operating expenses to operate as an independent publicly traded company, including various corporate functions, incremental information technology-related costs and incremental costs to operate standalone accounting, legal and other administrative functions. These functions were provided to the Company prior to the Separation by the Former Parent and will continue under a transition services agreement with the Former Parent or will be performed using the Company’s own resources. Unaudited Interim Financial Information The accompanying condensed consolidated financial statements of the Company for the three months ended March 31, 2024 are unaudited and have been prepared on a basis substantially consistent with the audited financial statements for the year ended December 31, 2023. The condensed consolidated financial statements for the three months ended March 31, 2023 were derived from the Former Parent’s audited financial statements. The year-end condensed consolidated balance sheet data, which are presented for comparative purposes, were derived from audited financial statements but do not include all disclosures required by GAAP. In the opinion of management, the condensed consolidated financial statements include all adjustments of a normal recurring nature that are necessary to state fairly the results of operations for the reported periods. The financial data and other information disclosed in these notes related to the three months ended March 31, 2024 and 2023 are also unaudited. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to the rules and regulations of the SEC for interim financial statements. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited annual consolidated financial statements as of and for the year ended December 31, 2023 and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023 (the “Annual Report on Form 10-K”). The results for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024 , any other interim periods, or any future year or period. Use of Estimates The preparation of the Company’s unaudited condensed consolidated financial statements in accordance with GAAP requires the Company to make estimates, judgments and assumptions that may affect the reported amounts of assets, liabilities and expenses and the related disclosure of contingent assets and liabilities. On an ongoing basis, the Company evaluates its estimates and judgments and methodologies, including but not limited to, those related to allocations of expenses, assets and liabilities from the Former Parent’s historical financials to the Company, the impairment of long-lived assets, and measurement of share-based compensation, leases, and income taxes including the valuation allowance for deferred tax assets. The Company bases its estimates on historical experience of the Former Parent and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ from these estimates under different assumptions or conditions. Significant Accounting Policies The significant accounting policies used in preparation of these unaudited condensed consolidated financial statements as of and for the three months ended March 31, 2024 and 2023 are consistent with those discussed herein and in Note 2, Basis of Presentation and Summary of Significant Accounting Policies , in the “Notes to Consolidated Financial Statements” accompanying the Company’s Annual Report on Form 10-K. Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (the “FASB”) or other standard-setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280), Improvements to Reportable Segment Disclosures (“ASU 280”). ASU 280 requires public entities to disclose significant segment expenses that are regularly provided to the chief operating decision maker and to disclose how reported measures of segment profit or loss are used in assessing segment performance and allocating resources. The amendments in ASU-280 are effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is evaluating the impact of the adoption of ASU-280 on its consolidated financial statements and related disclosures and does not expect the adoption of ASU-280 to have a material impact on the Company’s consolidated financial statements. In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU-740”). ASU-740 requires public entities to provide enhanced disclosure of specific categories of reconciling items included in the rate reconciliation; disclosure of the nature, effect and underlying causes of each reconciling item in the rate reconciliation and the judgment used in the categorization of such items; and enhanced disclosures for income taxes paid. The amendments in this ASU are effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is evaluating the impact of the adoption of ASU-740 on its consolidated financial statements and disclosures.

Cash, Cash Equivalents and Mark

Cash, Cash Equivalents and Marketable Securities	3 Months Ended
	Mar. 31, 2024
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Marketable Securities	3. Cash, Cash Equivalents and Marketable Securities As of March 31, 2024, the Company had cash and cash equivalents of $ 107.3 million and marketable securities of $ 124.4 million . As of December 31, 2023, the Company had cash and cash equivalents of $ 270.9 million and no marketable securities. In addition, the Company had a long-term restricted cash balance of $ 2.0 million and $ 0.3 million as of March 31, 2024 and December 31, 2023, respectively, which was restricted for a letter of credit and for use pertaining to corporate credit cards. See Note 7, Leases , for additional information regarding the letter of credit. Cash and cash equivalents are carried at cost, which approximates fair market value. Marketable securities are classified as available for sale and are recorded at fair value with the related unrealized gains and losses included in accumulated other comprehensive income, a component of equity. All of the realized gains and losses on the sale of these marketable securities are determined using the specific identification method. There were no realized gains or losses as of March 31, 2024. Marketable securities, all of which had maturities of less than one year, consisted of the following: March 31, 2024 (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Marketable securities: U.S. treasury securities $ 97,490 $ — $ ( 28 ) $ 97,462 U.S. government agency bonds 26,995 — ( 46 ) 26,949 Total marketable securities $ 124,485 $ — $ ( 74 ) $ 124,411 T he following table shows the fair value and gross unrealized losses of the Company’s marketable securities with unrealized losses that are not deemed to have credit losses and for which an allowance for credit losses has not been recorded, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of March 31, 2024. It is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost bases. Less than 12 months (in thousands) Estimated Fair Value Unrealized Losses Marketable securities with unrealized losses: U.S. treasury securities 90,597 ( 28 ) U.S. government agency bonds 26,949 ( 46 ) Total $ 117,546 $ ( 74 )

Fair Value

Fair Value	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value	4. Fair Value The following table presents information about the Company’s financial assets measured and recognized at fair value on a recurring basis classified under the appropriate level of the fair value hierarchy as of March 31, 2024. The fair value of these financial assets was determined based on three levels of input as follows: • Level 1 - Quoted prices in active markets for identical assets; • Level 2 - Observable inputs other than quoted prices in active markets; and • Level 3 - Unobservable inputs. (in thousands) March 31, 2024 Level 1 Level 2 Level 3 Assets: Money market mutual funds in cash equivalents $ 106,639 $ 106,639 $ — $ — Marketable securities: U.S. treasury securities 97,462 — 97,462 — U.S. government agency bonds 26,949 — 26,949 — Total $ 231,050 $ 106,639 $ 124,411 $ — The following table presents information about the Company’s financial assets measured and recognized at fair value on a recurring basis classified under the appropriate level of the fair value hierarchy as of December 31, 2023. (in thousands) December 31, 2023 Level 1 Level 2 Level 3 Assets: Money market mutual funds in cash equivalents $ 268,720 $ 268,720 $ — $ — Total $ 268,720 $ 268,720 $ — $ —

Property and Equipment, Net

Property and Equipment, Net	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	5. Property and Equipment, Net Property and equipment, net consisted of the following: March 31, December 31, (in thousands) 2024 2023 Furniture, fixtures and equipment $ 21,793 $ 21,738 Leasehold improvements 23,333 23,333 Construction in progress 15 15 Subtotal 45,141 45,086 Less: accumulated depreciation ( 34,529 ) ( 33,683 ) Total property and equipment, net $ 10,612 $ 11,403 Depreciation expense was $ 0.8 million and $ 0.5 million for the three months ended March 31, 2024 and 2023 , respectively.

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2024
Payables and Accruals [Abstract]
Accrued Expenses	6. Accrued Expenses Accrued expenses consisted of the following: March 31, December 31, (in thousands) 2024 2023 Accrued external research and development services $ 8,105 $ 8,543 Accrued compensation 3,049 5,858 Accrued general and administrative 2,290 2,545 Accrued other 80 — Total accrued expenses $ 13,524 $ 16,946

Leases

Leases	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Leases	7. Leases The Company’s only lease as of March 31, 2024 and December 31, 2023 was an operating lease for approximately 180,000 square feet of corporate office space, administrative areas and laboratories at 850 and 852 Winter Street in Waltham, Massachusetts, which includes 34,000 square feet of laboratory space (as amended, the “Winter Street Lease”). Under the terms of the Winter Street Lease, the Company also has the ability to sub-lease its corporate office and laboratory space. The original lease commenced in 2010 and was extended, at the Former Parent’s option, for approximately five years in 2020. The lease extension commenced in March 2021 for approximately 163,000 square feet of space and in September 2021 for the remaining approximately 17,000 square feet of space. The Winter Street Lease expires in 2026 and includes a tenant option to extend the term of the lease for an additional five-year period, which the Company is not reasonably certain to exercise. The Winter Street Lease was assigned to the Company in connection with the Separation and is used solely for operations of the Company. The Former Parent has been primarily obligated to the landlord for the Winter Street Lease, and, following the Separation, the Former Parent is jointly and severally liable with the Company for, and continues to guarantee, all obligations under the Winter Street Lease. As of December 31, 2023, the Former Parent was the applicant with respect to a letter of credit security deposit that secured the obligations of the tenant under the Winter Street Lease. The Former Parent maintained a $ 1.9 million collateralized letter of credit (the “Former Parent Letter of Credit”) related to such security deposit as of December 31, 2023. As the Company did not have legal ownership over any bank accounts prior to the Separation, there were no cash or cash equivalents balances specifically attributable to the Company for the historical periods presented and, accordingly, no amount related to the Former Parent Letter of Credit was reflected in the consolidated financial statements prior to the Separation. On January 3, 2024, the Company entered into a $ 1.7 million collateralized letter of credit that secures the obligations of the tenant under the Winter Street Lease. This letter of credit replaced the $ 1.9 million Former Parent Letter of Credit. As of the three months ended March 31, 2024 and 2023 , the incremental borrowing rate for the Winter Street Lease was 3.52 %. As of March 31, 2024 , the remaining term for the operating lease was 2.6 years. During each of the three months ended March 31, 2024 and 2023 , cash paid by the Company and, prior to the Separation, by the Former Parent, for amounts included for the measurement of lease liabilities was $ 1.6 million, and is included within cash flows from operating activities. The following table summarizes the effect of lease costs in the Company’s unaudited condensed consolidated statements of operations and comprehensive loss: Three Months Ended March 31, (in thousands) 2024 2023 Operating lease cost $ 1,406 $ 1,550 Variable lease cost 1,235 1,199 Total lease cost $ 2,641 $ 2,749 Future lease payments under non-cancelable leases as of March 31, 2024 consisted of the following: (in thousands) March 31, Remainder of 2024 $ 4,895 2025 6,642 2026 2,484 Total operating lease payments $ 14,021 Less: imputed interest ( 535 ) Total operating lease liabilities $ 13,486

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Share-Based Compensation	8. Share-Based Compensation 2023 Stock Option and Incentive Plan The Company’s 2023 Stock Option and Incentive Plan (the “2023 Plan”), which became effective on October 30, 2023, provides for the grant of up to 5,000,000 of the Company’s ordinary shares. The 2023 Plan allows the Company to make equity-based and cash-based incentive awards such as stock options, share appreciation rights, RSUs, restricted share awards, unrestricted share awards, cash-based awards, and dividend equivalent rights to officers, employees, non-employee directors, and consultants, subject to the provisions of the 2023 Plan. Option awards must be granted with an exercise price per ordinary share at least equal to the fair value of one ordinary share on the date of grant. The term of each option award will be fixed by the 2023 Plan Administrator and may not exceed 10 years from the date of grant. Stock options granted generally vest over a four-year period, with 25 % vesting on the one-year anniversary of the grant date and the remaining 75 % vesting quarterly over the remaining three years , assuming continued service, and with vesting acceleration in full immediately prior to a change in control. RSUs generally vest and are settled over a four-year period, with 25 % vesting and settling upon each of the first four anniversaries of the grant date. The 2023 Plan provides that the number of shares reserved and available for issuance under the 2023 Plan will be automatically increased on January 1, 2025, and each January 1 thereafter, in an amount equal to (i) 5 % of the outstanding number of the Company’s ordinary shares on the immediately preceding December 31, or (ii) such lesser number of shares as determined by the 2023 Plan Administrator. The ordinary shares underlying any awards under the 2023 Plan that are forfeited, cancelled or held back upon exercise of settlement of an award to satisfy the exercise price or any tax withholding obligation, or are otherwise terminated or forfeited (other than by exercise) will be added back to the ordinary shares available for issuance under the 2023 Plan. At March 31, 2024 , 430,191 ordinary shares were reserved and available for issuance under the 2023 Plan. 2023 Employee Stock Purchase Plan The Company’s 2023 Employee Stock Purchase Plan (the “ESPP”) became effective on October 30, 2023. The ESPP initially reserves and authorizes the issuance of up to a total of 100,000 of the Company’s ordinary shares to participating employees. The ESPP provides that the number of shares reserved and available for issuance will automatically increase on January 1, 2025 and each January 1 thereafter through January 1, 2034, by the least of (i) 100,000 ordinary shares, (ii) 1 % of the outstanding number of ordinary shares on the immediately preceding December 31, or (iii) such lesser number of ordinary shares as determined by the administrator of the ESPP. The number of shares reserved under the ESPP is subject to adjustment in the event of a share split, share dividend, or other change in the Company’s capitalization. 2024 Inducement Stock Option and Incentive Plan The Company’s 2024 Inducement Stock Option and Incentive Plan (the “2024 Plan”), which became effective on January 12, 2024, provides for the grant of up to 300,000 of the Company’s ordinary shares. The 2024 Plan allows the Company to make equity-based incentive awards such as non-qualified stock options, share appreciation rights, RSUs, restricted share awards, unrestricted share awards, and dividend equivalent rights to persons who (a) were not previously an employee or director of the Company or (b) are commencing employment with the Company following a bona fide period of non-employment with the Company, in either case as an inducement material to the individual’s entering into employment with the Company and in accordance with the requirements of Nasdaq Stock Market Rule 5635(c)(4), subject to the provisions of the 2024 Plan. The 2024 Plan is administered by the Company’s Board of Directors, which may in turn delegate authority to administer the plan to a committee of the Board of Directors, referred to herein as the 2024 Plan Administrator. Subject to the terms of the 2024 Plan, the 2024 Plan Administrator has the authority to determine recipients, the number of shares subject to awards to be granted, the type of award, and the terms and conditions of the awards, including the exercise period and vesting terms. The fair market value of the shares on any given date is determined in good faith by the 2024 Plan Administrator; provided, however, that if the shares are listed on a national securities exchange or traded on any established market, the determination is made by reference to the closing price on such date. If there is no closing price for such date, the determination is made by reference to the last date preceding such date for which there is a closing price. Option awards must be granted with an exercise price per ordinary share at least equal to the fair value of one ordinary share on the date of grant. The term of each option award will be fixed by the 2024 Plan Administrator and may not exceed 10 years from the date of grant. Stock options granted generally vest over a four-year period, with 25 % vesting on the one-year anniversary of the grant date and the remaining 75 % vesting quarterly over the remaining three years, assuming continued service, and with vesting acceleration in full immediately prior to a change in control. RSUs generally vest and are settled over a four-year period, with 25 % vesting and settling upon each of the first four anniversaries of the grant date. The ordinary shares underlying any awards under the 2024 Plan that are forfeited, cancelled or held back upon exercise of settlement of an award to satisfy the exercise price or any tax withholding obligation, or are otherwise terminated or forfeited (other than by exercise) will be added back to the ordinary shares available for issuance under the 2024 Plan. At March 31, 2024 , 279,000 ordinary shares were reserved and available for issuance under the 2024 Plan. Converted Awards On November 13, 2023, the Company entered into the employee matters agreement with the Former Parent under which the Company agreed to convert all outstanding Former Parent stock options and RSUs held by the Company’s employees under the Former Parent’s share-based compensation plans into the Company stock options and RSUs under the 2023 Plan in accordance with the conversion ratio set forth in the agreement. On December 14, 2023, the Former Parent and the Company amended the employee matters agreement to adjust the conversion ratio used to calculate the number of the Company’s RSUs issuable to each employee in exchange for each RSU of the Former Parent. All outstanding equity awards held by the Company’s employees were converted and issued under the 2023 Plan in December 2023 in accordance with the amended employee matters agreement. Except for the number of underlying shares and the exercise price of the stock options, the converted awards retain substantially the same terms and conditions of the original awards, including their term and vesting conditions. Former Parent Share-based Compensation Plans The Former Parent had share-based compensation plans which provided for granting equity awards, including non-qualified and incentive stock options, RSUs, RSU awards, cash-based awards, and performance shares to employees, officers and directors of, and consultants to, the Former Parent. Prior to the Separation, all share-based compensation plans were managed on a consolidated basis by the Former Parent and share-based compensation expense was allocated to the Company related to stock options, time-based RSU awards and performance-based RSU awards issued by the Former Parent. Accordingly, the amounts presented for periods prior to the Separation are not necessarily indicative of future share-based compensation and do not necessarily reflect the amount that the Company would have issued as an independent company for the periods presented. Stock Plan Activity The following average assumptions were used to estimate the fair value of stock options granted by the Company three months ended March 31, 2024 using the Black-Scholes option pricing model: Three Months Ended March 31, 2024 Risk-free interest rate 4.1 % Dividend rate 0 % Expected volatility 87.4 % Expected life (years) 6.2 A summary of stock option activity under the 2023 Plan and the 2024 Plan for the three months ended March 31, 2024 is as follows: Number of Options Weighted-Average Exercise Price Options outstanding at December 31, 2023 3,348,715 $ 4.53 Granted 359,874 $ 5.37 Cancelled/forfeited ( 338,687 ) $ 4.64 Options outstanding at March 31, 2024 3,369,902 $ 4.61 Options exercisable at March 31, 2024 1,355,800 $ 4.65 The weighted average grant date fair value of stock options granted during the three months ended March 31, 2024 was $ 4.05 . At March 31, 2024 , there were 3.1 million stock options vested or expected to vest, with a weighted average exercise price of $ 4.61 per share, a weighted average contractual remaining life of 6.8 years and an aggregate intrinsic value of $ 1.8 million. At March 31, 2024 , the aggregate intrinsic value of stock options exercisable was $ 0.8 million with a weighted average remaining contractual term of 4.7 years. The number of stock options expected to vest was determined by applying the pre-vesting forfeiture rate to the total number of outstanding options. The intrinsic value of a stock option is the amount by which the market value of the underlying shares exceeds the exercise price of the stock option. At March 31, 2024 , there was $ 4.4 million of unrecognized share-based compensation expense related to unvested stock options, which is expected to be recognized over a weighted average period of 1.9 years. A summary of RSU activity under the 2023 Plan and the 2024 Plan for the three months ended March 31, 2024 is as follows: Number of Shares Weighted-Average Grant Date Fair Value Per Share Unvested outstanding at December 31, 2023 1,129,512 $ 4.45 Granted 193,776 $ 5.34 Vested ( 232,810 ) $ 4.32 Cancelled/forfeited ( 102,381 ) $ 4.70 Unvested outstanding at March 31, 2024 988,097 $ 4.63 At March 31, 2024 , there was $ 3.2 million of unrecognized share-based compensation expense related to unvested RSUs, which will be recognized over a weighted average remaining contractual term of 1.8 years. The following table represents share-based compensation expense included in the Company’s unaudited condensed consolidated statements of operations and comprehensive loss: Three Months Ended (in thousands) 2024 2023 Research and development $ 1,066 $ 2,222 General and administrative 1,133 531 Total share-based compensation expense $ 2,199 $ 2,753

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	9. Income Taxes During the three months ended March 31, 2024, the Company recorded no tax provision expense. During the three months ended March 31, 2023, the Company recorded income tax provisions of $ 2.3 million related to its U.S. entity. The income tax provision was primarily due to the capitalization and amortization of R&D expenses in accordance with Section 174 of the Code. The provision was calculated on a separate return basis and is not necessarily representative of the tax provision that may arise in the future. Net operating losses previously reported by the Former Parent did not carry over to the Company after the Separation. On a quarterly basis, the Company reassesses the valuation allowance on its deferred tax assets, weighing positive and negative evidence to determine the recoverability of such deferred tax assets. In the first quarter of 2024, the Company reassessed the valuation allowance and considered all positive and negative evidence, including its cumulative losses over the year ended December 31, 2023 and the three months ended March 31, 2024 and concluded that it should maintain the valuation allowance on its Irish net operating losses and other Irish and U.S. deferred tax assets as of March 31, 2024 .

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies The Company, from time to time, may be involved with lawsuits arising in the ordinary course of business. the Company is not involved in any pending legal proceedings that it believes could have a material adverse effect on its financial condition, results of operations or cash flows. In the normal course of business, the Company contracts with third parties for preclinical, clinical and other research and development services. These contracts generally do not contain minimum purchase commitments and are cancellable upon notice by the Company. The Company has, however, entered into agreements with contract manufacturing organizations that include noncancellable costs or that may be subject to cancellation fees. As of March 31, 2024 , open purchase commitments for such noncancellable contract manufacturing costs totaled approximately $ 10.5 million. See Note 7, Leases , for information related to the Company’s lease obligations. See Note 1, Organization and Description of Business , for information related to the tax matters agreement, which governs the Company’s and the Former Parent’s respective rights, responsibilities, and obligations with respect to taxes and which contains certain indemnifications.

Related Parties

Related Parties	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
Related Parties	12. Related Parties Corporate expenses prior to the Separation represent shared costs of the Former Parent that have been allocated to the Company based on a systematic and rational methodology and are reflected as expenses in these unaudited condensed consolidated financial statements. These amounts include, but are not limited to, items such as general management and executive oversight, costs to support the Company’s information technology infrastructure, facilities, compliance, human resources, legal and finance functions, risk management, and share-based compensation administration, all of which support the operations of the Former Parent as a whole. Corporate expense allocations in the periods prior to the Separation were generally allocated to the Company based on proportional cost allocation methods using headcount, square footage, or proportional hours worked supporting the Company and other organizational activities, as applicable, which are considered to be reasonable reflections of the utilization of services provided or benefit received by the Company during the periods presented. Total corporate expense allocations from the Former Parent for the periods prior to the Separation in general and administrative expenses were $ 3.7 million during the three months ended March 31, 2023 . Total corporate expense allocations from the Former Parent for the periods prior to the Separation in R&D expenses were $ 40.4 million during the three months ended March 31, 2023. The Former Parent assumed all of the outstanding accrued liabilities and accounts payable related to the oncology business as of the date of the Separation. Management considers the allocation methodologies used to be reasonable and appropriate reflections of the related expenses attributable to the Company for purposes of the unaudited condensed consolidated financial statements; however, the expenses reflected in these unaudited condensed consolidated financial statements may not be indicative of the actual expenses that would have been incurred during the periods presented if the Company had operated as a standalone entity. In addition, the expenses reflected in the unaudited condensed consolidated financial statements may not be indicative of expenses that will be incurred in the future by the Company. See Note 1, Organization and Description of Business , for details of the Company’s cash and financing arrangements. As of the date these unaudited condensed consolidated financial statements were available for issuance, there were no existing intercompany debt or other financing agreements in place with the Former Parent. As of March 31, 2024, the Company had a receivable from the Former Parent of $ 1.9 million pursuant to the transition services agreements. During the three months ended March 31, 2024 , the Company received $ 4.9 million from the Former Parent and paid $ 4.0 million to the Former Parent pursuant to the transition services agreements. See Note 2, Basis of Presentation and Summary of Significant Accounting Policies , for additional information on the preparation and basis of presentation of these consolidated financial statements, including the treatment of certain R&D costs not directly attributable to individual programs, cash and cash equivalents, share-based compensation, and 401(k) Plan expenses. As of the date of the Separation, the Former Parent is no longer a related party to the Company.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Earnings per Share	11. Net Loss per Share Basic net loss per share is computed by dividing the net loss in each period by the weighted average number of ordinary shares outstanding during such period. Diluted net loss per share is computed similarly to basic net loss per share except that the denominator is increased to include the number of additional ordinary shares that would have been outstanding if the potential ordinary shares had been issued and if the additional ordinary shares were dilutive. For the periods presented, ordinary share equivalents, consisting of share-based awards, were not included in the calculation of the diluted net loss per share because to do so would be anti-dilutive. There were no dilutive equity instruments as of March 31, 2023 as there were no equity awards of the Company’s ordinary shares prior to the Separation. On November 15, 2023, the effective date of the Distribution, 16,689,740 of the Company’s ordinary shares were distributed to the Former Parent’s shareholders of record as of November 6, 2023, the record date for the Distribution. This share amount was utilized for the calculation of basic and diluted earnings per share for periods prior to the Separation as there were no shares of the Company outstanding prior to the Separation. As of March 31, 2024 and 2023, the number of ordinary shares underlying potentially dilutive securities consist of: March 31, 2024 2023 Options to purchase ordinary shares 3,369,902 — Restricted share units 988,097 — Total 4,357,999 —

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of Mural Oncology plc and its wholly-owned subsidiaries. For the periods prior to the Separation, the accompanying unaudited condensed consolidated financial statements of the Company have been prepared on a standalone basis and are derived from the Former Parent’s consolidated financial statements and accounting records. All intercompany transactions and accounts within the Company have been eliminated. The unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and, for the periods prior to the Separation, reflect the historical results of operations, financial position and cash flows of Mural, as included in the consolidated financial statements of the Former Parent and using the Former Parent’s historical accounting policies. For the periods prior to the Separation, these unaudited condensed consolidated financial statements do not purport to reflect what the Company’s results of operations, financial position or cash flows would have been had the Company operated as a standalone public company prior to the Separation, nor are they necessarily indicative of the Company’s future results of operations, financial position, or cash flows. As the Company’s operations were not historically held by a single legal entity or separate legal entities, net parent investment is shown in lieu of stockholders’ equity in the historical combined financial statements for the periods prior to the Separation. Net parent investment represents the cumulative investment by the Former Parent in the Company through the dates presented, inclusive of operating results. All transactions between the Company and the Former Parent are considered to be effectively settled in the unaudited condensed consolidated financial statements at the time the transaction is recorded. The effects of the settlement of these transactions between the Company and the Former Parent are reflected in the unaudited condensed consolidated statements of cash flows as “Net transfers from Former Parent” within financing activities and in the unaudited condensed consolidated statements of equity (deficit) as “Net parent investment.” Historically, the Company was dependent upon the Former Parent for all of its working capital and financing requirements, as the Former Parent used a centralized approach to cash management and financing its operations. There were no cash amounts specifically attributable to the Company for the historical periods presented prior to the Separation. Financing transactions prior to the Separation related to the Former Parent are accounted for as a financing activity on the accompanying unaudited condensed consolidated statements of cash flows through the date of the Separation. In connection with the Separation, certain assets and liabilities that were included on the consolidated balance sheet prior to the Separation were retained by the Former Parent and were therefore adjusted through net parent investment in the Company’s consolidated financial statements. The unaudited condensed consolidated financial statements of the Company include, for the periods prior to the Separation, the assets, liabilities, and expenses of the Former Parent that management has determined are specifically identifiable to the Company, such as those related to direct internal and external R&D activities as well as leases and fixed assets specifically identifiable to the oncology business. Based on the nature of the Company as a pre-revenue, development-stage biotechnology company, the unaudited condensed consolidated financial statements of the Company do not include any revenue or commercial expenses of the Former Parent. The unaudited condensed consolidated financial statements of the Company also include, for the periods prior to the Separation, an allocation of costs that were not directly attributable to the operations of the Company, including the costs of general and administrative support functions that were provided by the Former Parent, such as senior management, information technology, legal, accounting and finance, human resources, facility, and other corporate services. In addition, the Company’s unaudited condensed consolidated financial statements include, for the periods prior to the Separation, an allocation of certain R&D costs not directly attributable to individual programs. These costs have been allocated to the Company for the purposes of preparing the unaudited condensed consolidated financial statements based on proportional cost allocation methods using headcount, square footage or proportional hours worked supporting the Company and other organizational activities, as applicable, which are considered to be reasonable reflections of the utilization of services provided or benefit received by the Company during the periods presented. Management considers that such allocations have been made on a reasonable basis; however, these allocations may not necessarily be indicative of the costs that would have been incurred if the Company had operated on a standalone basis for the periods presented and, therefore, may not reflect the Company’s results of operations, financial position, and cash flows had the Company operated as a standalone entity during the periods presented. See Note 12, Related Parties , for additional information regarding related-party transactions with the Former Parent. The Company expects to incur additional operating expenses to operate as an independent publicly traded company, including various corporate functions, incremental information technology-related costs and incremental costs to operate standalone accounting, legal and other administrative functions. These functions were provided to the Company prior to the Separation by the Former Parent and will continue under a transition services agreement with the Former Parent or will be performed using the Company’s own resources.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying condensed consolidated financial statements of the Company for the three months ended March 31, 2024 are unaudited and have been prepared on a basis substantially consistent with the audited financial statements for the year ended December 31, 2023. The condensed consolidated financial statements for the three months ended March 31, 2023 were derived from the Former Parent’s audited financial statements. The year-end condensed consolidated balance sheet data, which are presented for comparative purposes, were derived from audited financial statements but do not include all disclosures required by GAAP. In the opinion of management, the condensed consolidated financial statements include all adjustments of a normal recurring nature that are necessary to state fairly the results of operations for the reported periods. The financial data and other information disclosed in these notes related to the three months ended March 31, 2024 and 2023 are also unaudited. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to the rules and regulations of the SEC for interim financial statements. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited annual consolidated financial statements as of and for the year ended December 31, 2023 and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023 (the “Annual Report on Form 10-K”). The results for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024 , any other interim periods, or any future year or period.
Use of Estimates	Use of Estimates The preparation of the Company’s unaudited condensed consolidated financial statements in accordance with GAAP requires the Company to make estimates, judgments and assumptions that may affect the reported amounts of assets, liabilities and expenses and the related disclosure of contingent assets and liabilities. On an ongoing basis, the Company evaluates its estimates and judgments and methodologies, including but not limited to, those related to allocations of expenses, assets and liabilities from the Former Parent’s historical financials to the Company, the impairment of long-lived assets, and measurement of share-based compensation, leases, and income taxes including the valuation allowance for deferred tax assets. The Company bases its estimates on historical experience of the Former Parent and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ from these estimates under different assumptions or conditions.
Significant Accounting Policies	Significant Accounting Policies The significant accounting policies used in preparation of these unaudited condensed consolidated financial statements as of and for the three months ended March 31, 2024 and 2023 are consistent with those discussed herein and in Note 2, Basis of Presentation and Summary of Significant Accounting Policies , in the “Notes to Consolidated Financial Statements” accompanying the Company’s Annual Report on Form 10-K.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (the “FASB”) or other standard-setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280), Improvements to Reportable Segment Disclosures (“ASU 280”). ASU 280 requires public entities to disclose significant segment expenses that are regularly provided to the chief operating decision maker and to disclose how reported measures of segment profit or loss are used in assessing segment performance and allocating resources. The amendments in ASU-280 are effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is evaluating the impact of the adoption of ASU-280 on its consolidated financial statements and related disclosures and does not expect the adoption of ASU-280 to have a material impact on the Company’s consolidated financial statements. In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU-740”). ASU-740 requires public entities to provide enhanced disclosure of specific categories of reconciling items included in the rate reconciliation; disclosure of the nature, effect and underlying causes of each reconciling item in the rate reconciliation and the judgment used in the categorization of such items; and enhanced disclosures for income taxes paid. The amendments in this ASU are effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is evaluating the impact of the adoption of ASU-740 on its consolidated financial statements and disclosures.

Cash, Cash Equivalents and Ma_2

Cash, Cash Equivalents and Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2024
Cash and Cash Equivalents [Abstract]
Schedule of Marketable Securities	Marketable securities, all of which had maturities of less than one year, consisted of the following: March 31, 2024 (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Marketable securities: U.S. treasury securities $ 97,490 $ — $ ( 28 ) $ 97,462 U.S. government agency bonds 26,995 — ( 46 ) 26,949 Total marketable securities $ 124,485 $ — $ ( 74 ) $ 124,411
Schedule of Marketable Securities in Continuous Unrealized Loss Position	T he following table shows the fair value and gross unrealized losses of the Company’s marketable securities with unrealized losses that are not deemed to have credit losses and for which an allowance for credit losses has not been recorded, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of March 31, 2024. It is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost bases. Less than 12 months (in thousands) Estimated Fair Value Unrealized Losses Marketable securities with unrealized losses: U.S. treasury securities 90,597 ( 28 ) U.S. government agency bonds 26,949 ( 46 ) Total $ 117,546 $ ( 74 )

Fair Value (Tables)

Fair Value (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Financial Assets Measured and Recognized at Fair Value on Recurring Basis	The following table presents information about the Company’s financial assets measured and recognized at fair value on a recurring basis classified under the appropriate level of the fair value hierarchy as of March 31, 2024. The fair value of these financial assets was determined based on three levels of input as follows: • Level 1 - Quoted prices in active markets for identical assets; • Level 2 - Observable inputs other than quoted prices in active markets; and • Level 3 - Unobservable inputs. (in thousands) March 31, 2024 Level 1 Level 2 Level 3 Assets: Money market mutual funds in cash equivalents $ 106,639 $ 106,639 $ — $ — Marketable securities: U.S. treasury securities 97,462 — 97,462 — U.S. government agency bonds 26,949 — 26,949 — Total $ 231,050 $ 106,639 $ 124,411 $ — The following table presents information about the Company’s financial assets measured and recognized at fair value on a recurring basis classified under the appropriate level of the fair value hierarchy as of December 31, 2023. (in thousands) December 31, 2023 Level 1 Level 2 Level 3 Assets: Money market mutual funds in cash equivalents $ 268,720 $ 268,720 $ — $ — Total $ 268,720 $ 268,720 $ — $ —

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following: March 31, December 31, (in thousands) 2024 2023 Furniture, fixtures and equipment $ 21,793 $ 21,738 Leasehold improvements 23,333 23,333 Construction in progress 15 15 Subtotal 45,141 45,086 Less: accumulated depreciation ( 34,529 ) ( 33,683 ) Total property and equipment, net $ 10,612 $ 11,403

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2024
Payables and Accruals [Abstract]
Components of Accrued Expenses	Accrued expenses consisted of the following: March 31, December 31, (in thousands) 2024 2023 Accrued external research and development services $ 8,105 $ 8,543 Accrued compensation 3,049 5,858 Accrued general and administrative 2,290 2,545 Accrued other 80 — Total accrued expenses $ 13,524 $ 16,946

Net Loss per Share (Tables)

Net Loss per Share (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Schedule of Number of Ordinary Shares Underlying Potentially Dilutive Securities	As of March 31, 2024 and 2023, the number of ordinary shares underlying potentially dilutive securities consist of: March 31, 2024 2023 Options to purchase ordinary shares 3,369,902 — Restricted share units 988,097 — Total 4,357,999 —

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Summary of Effect of Lease Costs in Unaudited Condensed Combined Statements of Operations	The following table summarizes the effect of lease costs in the Company’s unaudited condensed consolidated statements of operations and comprehensive loss: Three Months Ended March 31, (in thousands) 2024 2023 Operating lease cost $ 1,406 $ 1,550 Variable lease cost 1,235 1,199 Total lease cost $ 2,641 $ 2,749
Schedule of Future Lease Payments under Non-cancelable Leases	Future lease payments under non-cancelable leases as of March 31, 2024 consisted of the following: (in thousands) March 31, Remainder of 2024 $ 4,895 2025 6,642 2026 2,484 Total operating lease payments $ 14,021 Less: imputed interest ( 535 ) Total operating lease liabilities $ 13,486

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Summary of Assumption Estimate Fair Value of Stock Options Granted	The following average assumptions were used to estimate the fair value of stock options granted by the Company three months ended March 31, 2024 using the Black-Scholes option pricing model: Three Months Ended March 31, 2024 Risk-free interest rate 4.1 % Dividend rate 0 % Expected volatility 87.4 % Expected life (years) 6.2
Summary of Stock Option Activity	A summary of stock option activity under the 2023 Plan and the 2024 Plan for the three months ended March 31, 2024 is as follows: Number of Options Weighted-Average Exercise Price Options outstanding at December 31, 2023 3,348,715 $ 4.53 Granted 359,874 $ 5.37 Cancelled/forfeited ( 338,687 ) $ 4.64 Options outstanding at March 31, 2024 3,369,902 $ 4.61 Options exercisable at March 31, 2024 1,355,800 $ 4.65
Summary of Restricted Share Activity	A summary of RSU activity under the 2023 Plan and the 2024 Plan for the three months ended March 31, 2024 is as follows: Number of Shares Weighted-Average Grant Date Fair Value Per Share Unvested outstanding at December 31, 2023 1,129,512 $ 4.45 Granted 193,776 $ 5.34 Vested ( 232,810 ) $ 4.32 Cancelled/forfeited ( 102,381 ) $ 4.70 Unvested outstanding at March 31, 2024 988,097 $ 4.63
Schedule of Share-Based Compensation Expense	The following table represents share-based compensation expense included in the Company’s unaudited condensed consolidated statements of operations and comprehensive loss: Three Months Ended (in thousands) 2024 2023 Research and development $ 1,066 $ 2,222 General and administrative 1,133 531 Total share-based compensation expense $ 2,199 $ 2,753

Organization and Description _2

Organization and Description of Business - Additional Information (Details) - Alkermes - USD ($) $ in Millions	Nov. 15, 2023	Nov. 14, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Effective time of distribution		Nov. 15, 2023
Cash distribution received from parent		$ 275
Distribution term of shares	one ordinary share of the Company for every ten ordinary shares

Cash, Cash Equivalents and Ma_3

Cash, Cash Equivalents and Marketable Securities - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 107,263	$ 270,852
Marketable securities	124,411	0
Long-term restricted cash balance	$ 1,969	$ 300

Cash, Cash Equivalents and Ma_4

Cash, Cash Equivalents and Marketable Securities - Schedule of Marketable Securities (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Marketable Securities [Line Items]
Amortized Cost	$ 124,485
Gross Unrealized Losses	(74)
Estimated Fair Value	124,411
U.S. treasury securities
Marketable Securities [Line Items]
Amortized Cost	97,490
Gross Unrealized Losses	(28)
Estimated Fair Value	97,462
U.S. government agency bonds
Marketable Securities [Line Items]
Amortized Cost	26,995
Gross Unrealized Losses	(46)
Estimated Fair Value	$ 26,949

Cash, Cash Equivalents and Ma_5

Cash, Cash Equivalents and Marketable Securities - Schedule of Marketable Securities in Continuous Unrealized Loss Position (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Marketable Securities [Line Items]
Marketable securities with unrealized losses, Less than 12 months, Estimated Fair Value	$ 117,546
Marketable securities with unrealized losses, Less than 12 months, Unrealized Losses	(74)
U.S. treasury securities
Marketable Securities [Line Items]
Marketable securities with unrealized losses, Less than 12 months, Estimated Fair Value	90,597
Marketable securities with unrealized losses, Less than 12 months, Unrealized Losses	(28)
U.S. government agency bonds
Marketable Securities [Line Items]
Marketable securities with unrealized losses, Less than 12 months, Estimated Fair Value	26,949
Marketable securities with unrealized losses, Less than 12 months, Unrealized Losses	$ (46)

Fair Value - Financial Assets M

Fair Value - Financial Assets Measured and Recognized at Fair Value on Recurring Basis (Details) - Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 231,050	$ 268,720
Money Market Mutual Funds in Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	106,639	268,720
U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	97,462
U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	26,949
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	106,639	268,720
Level 1 | Money Market Mutual Funds in Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	106,639	$ 268,720
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	124,411
Level 2 | U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	97,462
Level 2 | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 26,949

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Subtotal	$ 45,141	$ 45,086
Less: accumulated depreciation	(34,529)	(33,683)
Total property and equipment, net	10,612	11,403
Furniture, Fixtures and Equipment
Property, Plant and Equipment [Line Items]
Subtotal	21,793	21,738
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Subtotal	23,333	23,333
Construction in Progress
Property, Plant and Equipment [Line Items]
Subtotal	$ 15	$ 15

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 846	$ 530

Accrued Expenses - Components o

Accrued Expenses - Components of Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued external research and development services	$ 8,105	$ 8,543
Accrued compensation	3,049	5,858
Accrued general and administrative	2,290	2,545
Accrued other	80	0
Total accrued expenses	$ 13,524	$ 16,946

Leases - Additional Information

Leases - Additional Information (Details) $ in Millions	1 Months Ended		3 Months Ended
	Sep. 30, 2021 ft²	Mar. 31, 2021 ft²	Mar. 31, 2024 USD ($) ft²	Mar. 31, 2023 USD ($)	Jan. 03, 2024 USD ($)	Dec. 31, 2023 USD ($) ft²
Lessee, Lease, Description [Line Items]
Area of Land | ft²	17,000	163,000	180,000			180,000
Lease commenced year			2010
Operating leases, options to extend leases term			5 years
Extended lease commenced month and year	2021-09	2021-03
Lease expiration year			2026
Incremental borrowing rate			3.52%
Remaining lease term			2 years 7 months 6 days
Winter Street Lease [Member]
Lessee, Lease, Description [Line Items]
Letter of credit					$ 1.7
Laboratory Space
Lessee, Lease, Description [Line Items]
Area of Land | ft²			34,000
Parent
Lessee, Lease, Description [Line Items]
Letter of credit security deposit						$ 1.9
Cash paid for amounts included for measurement of lease liabilities			$ 1.6	$ 1.6
Parent | Winter Street Lease [Member]
Lessee, Lease, Description [Line Items]
Letter of credit security deposit					$ 1.9

Leases - Summary of Effect of L

Leases - Summary of Effect of Lease Costs in Unaudited Condensed Combined Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Leases [Abstract]
Operating lease cost	$ 1,406	$ 1,550
Variable lease cost	1,235	1,199
Total lease costs	$ 2,641	$ 2,749

Leases - Schedule of Future Lea

Leases - Schedule of Future Lease Payments under Non-cancelable Leases (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Leases [Abstract]
Remainder of 2024	$ 4,895
2025	6,642
2026	2,484
Total operating lease payments	14,021
Less: imputed interest	(535)
Total operating lease liabilities	$ 13,486

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Assumption Estimate Fair Value of Stock Options Granted (Details)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement, Noncash Expense [Abstract]
Risk-free interest rate	4.10%
Dividend rate	0%
Expected volatility	87.40%
Expected life (years)	6 years 2 months 12 days

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Stock Option Activity (Details) - 2023 Plan and 2024 Plan	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options outstanding at December 31, 2023, Number of Options, Beginning Balance | shares	3,348,715
Granted, Number of Options | shares	359,874
Cancelled/forfeited, Number of Options | shares	(338,687)
Options outstanding at March 31, 2024, Number of Options, Ending Balance | shares	3,369,902
Options exercisable at March 31, 2024, Number of Options | shares	1,355,800
Options outstanding at December 31, 2023, Weighted-Average Exercise Price, Beginning Balance | $ / shares	$ 4.53
Granted,Weighted-Average Exercise Price | $ / shares	5.37
Cancelled/forfeited, Weighted-Average Exercise Price | $ / shares	4.64
Options outstanding at March 31, 2024, Weighted Average Exercise Price, Ending Balance | $ / shares	4.61
Options exercisable at March 31, 2024, Weighted-Average Exercise Price | $ / shares	$ 4.65

Share-Based Compensation - Su_3

Share-Based Compensation - Summary of Restricted Share Activity (Details) - 2023 Plan and 2024 Plan - Restricted Stock Units	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unvested outstanding at December 31, 2023, Beginning Balance | shares	1,129,512
Granted, Number of Shares | shares	193,776
Vested, Number of Shares | shares	(232,810)
Cancelled/forfeited | shares	(102,381)
Unvested outstanding at March 31, 2024 ,Number of Shares, Ending Balance | shares	988,097
Unvested outstanding at December 31, 2023, Weighted-Average Grant Date Fair Value Per Share, Beginning Balance | $ / shares	$ 4.45
Granted, Weighted-Average Grant Date Fair Value Per Share | $ / shares	5.34
Vested, Weighted-Average Grant Date Fair Value Per Share | $ / shares	4.32
Cancelled/forfeited, Weighted-Average Grant Date Fair Value Per Share | $ / shares	4.70
Unvested outstanding at March 31, 2024, Weighted-Average Grant Date Fair Value Per Share, Ending Balance | $ / shares	$ 4.63

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock authorized for issuance	5,000,000
Exercisable weighted average remaining contractual term	4 years 8 months 12 days
Aggregate intrinsic value of stock options exercisable | $	$ 0.8
Weighted average aggregate intrinsic value | $	$ 1.8
Weighted average contractual remaining life	6 years 9 months 18 days
Weighted average exercise price | $ / shares	$ 4.61
Stock options vested or expected to vest	3,100,000
Weighted-average grant date fair value of options | $ / shares	$ 4.05
Tranche One
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage	25%
2023 Stock Option and Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, description	The 2023 Plan provides that the number of shares reserved and available for issuance under the 2023 Plan will be automatically increased on January 1, 2025, and each January 1 thereafter, in an amount equal to (i) 5% of the outstanding number of the Company’s ordinary shares on the immediately preceding December 31, or (ii) such lesser number of shares as determined by the 2023 Plan Administrator.
Percentage of outstanding our common stock	5%
Vesting period	4 years
Options contractual term	10 years
Ordinary shares reserved and available for issuance	430,191
2023 Stock Option and Incentive Plan | Tranche One
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage	25%
2023 Stock Option and Incentive Plan | Tranche Two
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	3 years
Vesting percentage	75%
2023 Employee Stock Purchase Plan | Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock authorized for issuance	100,000
2023 Employee Stock Purchase Plan | Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock authorized for issuance	100,000
2023 Employee Stock Purchase Plan | Common Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Percentage of outstanding our common stock	1%
2024 Inducement Stock Option and Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options contractual term	10 years
Ordinary shares reserved and available for issuance	279,000
2024 Inducement Stock Option and Incentive Plan | Tranche One
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	4 years
2024 Inducement Stock Option and Incentive Plan | Tranche Two
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage	75%
Options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized share-based compensation expense | $	$ 4.4
Unvested stock options weighted average period	1 year 10 months 24 days
Restricted Stock Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized share-based compensation expense | $	$ 3.2
Unvested stock options weighted average period	1 year 9 months 18 days
Restricted Stock Units | 2023 Stock Option and Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	4 years
Vesting percentage	25%
Restricted Stock Units | 2024 Inducement Stock Option and Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	4 years
Vesting percentage	25%

Share-Based Compensation - Sche

Share-Based Compensation - Schedule of Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	$ 2,199	$ 2,753
Research and Development
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	1,066	2,222
General and Administrative
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	$ 1,133	$ 531

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income tax provisions	$ 0	$ 2,311

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Millions	Mar. 31, 2024 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Open purchase commitments for noncancellable contract manufacturing costs	$ 10.5

Net Loss Per Share (Additional

Net Loss Per Share (Additional Information) (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Nov. 15, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive equity instruments	4,357,999	0
Equity awards		0
Distribution of ordinary shares	16,922,550		16,689,740
Alkermes Plc. [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Distribution of ordinary shares				16,689,740

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Number of Ordinary Shares Underlying Potentially Dilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	4,357,999	0
Options to Purchase Ordinary Shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	3,369,902
Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	988,097

Related Parties - Additional In

Related Parties - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Related Party Transaction [Line Items]
General and administrative expense	$ 7,165	$ 3,746
Research and development expense	26,868	40,410
Receivable from former parent	1,895		$ 5,548
Corporate Expense Allocations | Alkermes
Related Party Transaction [Line Items]
General and administrative expense		3,700
Research and development expense		$ 40,400
Receivable from former parent	1,900
Cash received from former parent	4,900
Paid to former parent pursuant to transition services agreements	$ 4,000

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Nov. 15, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Distribution of ordinary shares	16,922,550		16,689,740
Equity awards		0
Dilutive equity instruments	4,357,999	0
Alkermes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Distribution of ordinary shares				16,689,740

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - Alkermes - USD ($) $ in Millions	Nov. 15, 2023	Nov. 14, 2023
Subsequent Event [Line Items]
Distribution term of shares	one ordinary share of the Company for every ten ordinary shares
Effective time of distribution		Nov. 15, 2023
Cash distribution received from parent		$ 275