IO Biotech (IOBT) 10-Q 17 Dec 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Dec. 16, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2021
Current Fiscal Year End Date	--12-31
Entity Registrant Name	IO Biotech, Inc.
Entity Central Index Key	0001865494
Entity File Number	001-41008
Entity Tax Identification Number	87-0909276
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	Ole Maaløes Vej 3
Entity Address, City or Town	Copenhagen N
Entity Address, Country	DK
Entity Address, Postal Zip Code	DK-2200
City Area Code	+45
Local Phone Number	7070 2980
Title of each class	Common Stock, par value $0.001 per share
Trading Symbol(s)	IOBT
Name of each exchange on which registered	NASDAQ
Entity Current Reporting Status	No
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 Bankruptcy Proceedings, Reporting Current	true
Entity Common Stock, Shares Outstanding		28,815,267
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 45,477	$ 3,405
Prepaid expenses and other current assets	6,516	2,230
Total current assets	51,993	5,635
Noncurrent assets	45	18
Total assets	52,038	5,653
Current liabilities
Accounts payable	2,166	522
Accrued expenses and other current liabilities	3,344	2,528
Preference shares tranche obligations	28,276
Total current liabilities	33,786	3,050
Total liabilities	33,786	3,050
Commitments and contingencies (Note 9)
Stockholders’ deficit
Additional paid-in capital	1,602	1,110
Accumulated deficit	(84,972)	(38,402)
Accumulated other comprehensive loss	705	1,961
Total stockholders’ deficit	(82,637)	(35,303)
Total liabilities, convertible preference shares and stockholders’ deficit	52,038	5,653
Class B Convertible Preference Stock
Convertible preference shares
Convertible preference shares	37,906	37,906
Class C Convertible Preference Stock
Convertible preference shares
Convertible preference shares	62,983
Class A Ordinary Shares
Stockholders’ deficit
Class A ordinary shares, par value of $0.16 per share; 177,200 shares authorized, issued and outstanding as of September 30, 2021 and December 31, 2020	$ 28	$ 28

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Class B Convertible Preference Stock
Convertible preference shares, par value	$ 0.16	$ 0.16
Convertible preference shares, shares authorized	584,583	584,583
Convertible preference shares, shares issued	584,583	584,583
Convertible preference shares, shares outstanding	584,583	584,583
Convertible preference shares, liquidation preference	$ 47,111
Class C Convertible Preference Stock
Convertible preference shares, par value	$ 0.16	$ 0.16
Convertible preference shares, shares authorized	1,263,804	0
Convertible preference shares, shares issued	538,088	0
Convertible preference shares, shares outstanding	538,088	0
Convertible preference shares, liquidation preference	$ 66,503
Class A Ordinary Shares
Ordinary shares, par value	$ 0.16	$ 0.16
Ordinary shares, shares authorized	177,200	177,200
Ordinary shares, shares issued	177,200	177,200
Ordinary shares, shares outstanding	177,200	177,200

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating expenses
Research and development	$ 4,128	$ 2,777	$ 13,712	$ 6,254
General and administrative	2,914	654	6,127	1,352
Total operating expenses	7,042	3,431	19,839	7,606
Loss from operations	(7,042)	(3,431)	(19,839)	(7,606)
Other income (expense)
Currency exchange gain (loss), net	17	(9)	309	90
Interest expense	(67)	(7)	(210)	(15)
Fair value adjustments on preference shares tranche obligations	2,630		(26,830)
Fair value adjustments on convertible notes		(41)		(1,957)
Total other income (expense), net	2,580	(57)	(26,731)	(1,882)
Net loss	(4,462)	(3,488)	(46,570)	(9,488)
Cumulative dividends on class B and C preference shares	(2,073)	(661)	(6,006)	(1,683)
Net loss attributable to class A ordinary shareholders	$ (6,535)	$ (4,149)	$ (52,576)	$ (11,171)
Net loss per class A ordinary share, basic and diluted	$ (36.88)	$ (23.41)	$ (296.70)	$ (63.04)
Weighted-average number of shares used in computing net loss per class A ordinary share, basic and diluted	177,200	177,200	177,200	177,200
Other comprehensive loss
Net loss	$ (4,462)	$ (3,488)	$ (46,570)	$ (9,488)
Foreign currency translation	(681)	248	(1,256)	487
Total comprehensive loss	$ (5,143)	$ (3,240)	$ (47,826)	$ (9,001)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Convertible Preference Shares and Stockholders' Deficit - USD ($) $ in Thousands	Total	Class B Convertible Preference Stock	Class C Convertible Preference Stock	Common StockClass A Ordinary Shares	Additional Paid-In Capital	Other Comprehensive Loss	Accumulated Deficit
Temporary equity, Balance at Dec. 31, 2019		$ 22,060
Temporary equity, Balance, shares at Dec. 31, 2019		366,301
Balance at Dec. 31, 2019	$ (23,531)			$ 28	$ 1,504	$ 1,297	$ (26,360)
Balance, shares at Dec. 31, 2019				177,200
Temporary equity, Issuance of class B preference shares upon conversion of convertible notes, net of issuance costs of $4		$ 10,273
Temporary equity, Issuance of class B preference shares upon conversion of convertible notes, net of issuance costs of $4, shares		142,437
Temporary equity, Issuance of preference shares, net of issuance costs		$ 5,573
Temporary equity, Issuance of preference shares, net of issuance costs, shares		75,845
Issuance of class B preference shares, net of issuance costs of $10	(466)				(466)
Equity-based compensation expense	48				48
Currency translation	487					487
Net loss	(9,488)						(9,488)
Temporary equity, Balance at Sep. 30, 2020		$ 37,906
Temporary equity, Balance, shares at Sep. 30, 2020		584,583
Balance at Sep. 30, 2020	(32,950)			$ 28	1,086	1,784	(35,848)
Balance, shares at Sep. 30, 2020				177,200
Temporary equity, Balance at Dec. 31, 2019		$ 22,060
Temporary equity, Balance, shares at Dec. 31, 2019		366,301
Balance at Dec. 31, 2019	(23,531)			$ 28	1,504	1,297	(26,360)
Balance, shares at Dec. 31, 2019				177,200
Net loss	(12,000)
Temporary equity, Balance at Dec. 31, 2020		$ 37,906
Temporary equity, Balance, shares at Dec. 31, 2020		584,583	0
Balance at Dec. 31, 2020	(35,303)			$ 28	1,110	1,961	(38,402)
Balance, shares at Dec. 31, 2020				177,200
Temporary equity, Issuance of preference shares, net of issuance costs			$ 62,983
Temporary equity, Issuance of preference shares, net of issuance costs, shares			538,088
Equity-based compensation expense	492				492
Currency translation	(1,256)					(1,256)
Net loss	(46,570)						(46,570)
Temporary equity, Balance at Sep. 30, 2021		$ 37,906	$ 62,983
Temporary equity, Balance, shares at Sep. 30, 2021		584,583	538,088
Balance at Sep. 30, 2021	$ (82,637)			$ 28	$ 1,602	$ 705	$ (84,972)
Balance, shares at Sep. 30, 2021				177,200

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Convertible Preference Shares and Stockholders' Deficit (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Class B Convertible Preference Stock
Temporary equity, issuance costs		$ 10
Temporary equity, issuance cost		$ 4
Class C Convertible Preference Stock
Temporary equity, issuance costs	$ 340

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net loss	$ (46,570)	$ (9,488)
Adjustment to reconcile net loss to net cash used in operating activities
Equity-based compensation	492	48
Fair value adjustments on preference shares tranche obligations	26,830
Fair value adjustments convertible notes		1,957
Other non-cash items, net	(307)	(90)
Changes in operating assets and liabilities
Prepaid expenses and other current assets	(4,286)	(175)
Accounts payable	1,644	(41)
Accrued expenses and other current liabilities	791	927
Net cash used in operating activities	(21,406)	(6,862)
Cash flows from investing activities
Purchase of property and equipment	(3)
Net cash used in investing activities	(3)
Cash flows from financing activities
Proceeds from issuance of preference shares	65,748	5,116
Preference shares issuance costs	(340)	(14)
Net cash provided by financing activities	65,408	5,102
Net increase (decrease) in cash and cash equivalents	43,999	(1,760)
Effect of exchange rate changes on cash and cash equivalents	(1,927)	(233)
Cash and cash equivalents, beginning of period	3,405	7,846
Cash and cash equivalents, end of period	$ 45,477	6,319
Supplemental disclosures of non-cash financing activities:
Exchange of convertible notes for class B preference shares		$ 10,277

Description of Business, Organi

Description of Business, Organization and Liquidity	9 Months Ended
	Sep. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business, Organization and Liquidity	1. Description of Business, Organization and Liquidity Business IO Biotech ApS, together with its consolidated subsidiaries, is a clinical-stage biotechnology company dedicated to the identification and development of disruptive immune therapies for the treatment of cancer. We are developing novel, immune-modulating cancer therapies based on our T-win technology platform. As used in these financial statements, unless the context otherwise requires, references to the “Company”, “we,” “us,” and “our” refer to IO Biotech ApS. We were incorporated in Denmark in December 2014. Risks and Uncertainties We are subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive pre-clinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance reporting capabilities. Our product candidates are in development. There can be no assurance that our research and development will be successfully completed, that adequate protection for our intellectual property will be obtained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if our product development efforts are successful, it is uncertain when, if ever, we will generate significant revenue from product sales. We operate in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, we are dependent upon the services of our employees and consultants. Liquidity Considerations Since inception, we have devoted substantially all our efforts to business planning, conducting research and development, recruiting management and technical staff, and raising capital. We have financed our operations primarily through the issuance of convertible preference shares, convertible notes and, most recently, our initial public offering, or IPO. Our continued discovery and development of its product candidates will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if product development efforts are successful, it is uncertain when, if ever, we will realize significant revenue from product sales. As of September 30, 2021, we had an accumulated deficit of $ 85.0 million. We have incurred losses and negative cash flows from operations since inception, including net losses of $ 46.6 million and $ 12.0 million for the nine months ended September 30, 2021 and the year ended December 31, 2020, respectively. We expect that our operating losses and negative cash flows will continue for the foreseeable future as we continue to develop our product candidates. We currently expect that our cash and cash equivalents of $ 45.5 million as of September 30, 2021 together with the gross cash proceeds of $ 84.1 million received in October 2021 from the issuance of 656,776 class C preference shares and the net proceeds from the IPO, after deducting underwriting discounts, commissions and offering costs, of $ 103.3 million in November 2021, which includes 1,072,500 shares issued upon the full exercise of the underwriters in November 2021 of their option to purchase additional shares of common stock, will be sufficient to fund our operating expenses and capital requirements for at least 12 months from the date the financial statements are issued. However, additional funding will be necessary to fund future discovery research, pre-clinical and clinical activities. We will seek additional funding through public financings, debt financings, collaboration agreements, strategic alliances and licensing arrangements. Although we have been successful in raising capital in the past, there is no assurance that we will be successful in obtaining such additional financing on terms acceptable to it, if at all, and we may not be able to enter into collaborations or other arrangements. If we are unable to obtain funding, we could be forced to delay, reduce or eliminate our research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect our business prospects, even our ability to continue operations. Coronavirus Pandemic In March 2020, the World Health Organization declared the COVID-19 outbreak a pandemic. In order to mitigate the spread of COVID-19, governments have imposed unprecedented restrictions on business operations, travel and gatherings, resulting in a global economic downturn and other adverse economic and societal impacts. The COVID-19 pandemic has also overwhelmed or otherwise led to changes in the operations of many healthcare facilities, including clinical trial sites. While we are considered an essential business under applicable regulations and continue to operate, the impacts of COVID-19 initially placed significant strain on our clinical trial sites, have raised concerns around monitoring patient safety, and resulted in changes to patient visit frequencies. We are continuing to work closely with our clinical partners and have taken steps as necessary to adjust our protocols and timelines due to the impact of the COVID-19 pandemic. The COVID-19 pandemic and its impacts continue to evolve. We cannot predict the scope and severity of any further disruptions as a result of COVID-19 or their impacts on us, but business disruptions for us or any of the third parties with whom we engage, including the collaborators, contract organizations, third-party manufacturers, suppliers, clinical trial sites, regulators and other third parties with whom we conduct business could materially and negatively impact our ability to conduct our business in the manner and on the timelines presently planned. The extent to which the COVID-19 pandemic may continue to impact our business and financial performance will depend on future developments, which are highly uncertain and cannot be predicted with confidence, including the scope and duration of the pandemic, the extent and effectiveness of government restrictions and other actions, including relief measures, implemented to address the impact of the pandemic, and resulting economic impacts. The actual and perceived impact of the COVID-19 pandemic is changing daily, and its ultimate effect on our business cannot be predicted. As a result, there can be no assurance that we will not experience additional negative impacts associated with COVID-19, which could be significant. The COVID-19 pandemic may negatively impact our business, financial condition and results of operations causing interruptions or delays in the Company’s programs and services.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies There have been no changes to the significant accounting policies as disclosed in Note 2 to the Company’s annual financial statements for the years ended December 31, 2020 and 2019 included in the final prospectus for the Company’s IPO filed pursuant to Rule 424(b)(4) under the Securities Act with the SEC on November 8, 2021 (the "Prospectus"). Principles of consolidation The Company’s condensed consolidated financial statements include the accounts of its subsidiaries IO Bio US, Inc. and IO Biotech Limited. IO Bio US, Inc., a wholly owned subsidiary of IO Biotech ApS, was incorporated in Delaware in May 2021. IO Biotech Limited, a wholly owned subsidiary of IO Biotech ApS, was incorporated in the UK in August 2021. In October 2021, the Company engaged in a series of transactions, referred to collectively as the Corporate Reorganization. As a result of the Corporate Reorganization, IO Biotech ApS became a wholly-owned subsidiary of IO Biotech, Inc. and accordingly, our consolidated financial statements will be those of IO Biotech, Inc. for the periods after the date of the Corporate Reorganization. IO Biotech, Inc. is a recently formed holding company, which, prior to our IPO, had nominal assets and no liabilities, contingencies, or commitments, and which has not conducted any operations prior to our IPO other than acquiring the entire issued and outstanding stock of IO Biotech ApS. The Company, IO Biotech ApS, and the holders of all of the issued and outstanding equity interests of IO Biotech ApS have entered into a Share Contribution and Exchange Agreement, dated as of October 29, 2021, pursuant to which the Corporate Reorganization was effected. Unaudited Financial Information The Company’s condensed financial statements included herein have been prepared in conformity with accounting principles generally accepted in the United States of America, or GAAP, and pursuant to the rules and regulations of the Securities and Exchange Commission, or SEC. In the Company’s opinion, the information furnished reflects all adjustments, all of which are of a normal and recurring nature, necessary for a fair presentation of the financial position and results of operations for the reported interim periods. The Company consider events or transactions that occur after the balance sheet date but before the financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year or any other interim period. Restatement of Prior Period Financial Statements. In connection with the preparation of our consolidated financial statements, we identified an error related to the recording of an accrued expense as of June 30, 2021, which led to the overstatement of research and development expenses for the six months ended June 30, 2021. As previously disclosed in our Current Report on Form 8-K filed on December 17, 2021, we have restated our previously reported Unaudited Interim Condensed Financial Statements as of June 30, 2021 and for the Six Months Ended June 30, 2021 and 2020 for this error. Recently Issued Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) , as amended, with guidance regarding the accounting for and disclosure of leases. ASU 2016-02 requires lessees to recognize the liabilities related all leases, including operating leases, with a term greater than 12 months on the balance sheet. This update also requires lessees and lessors to disclose key information about their leasing transactions. This standard is effective for annual reporting periods beginning after December 15, 2021, and interim periods within annual periods beginning after December 15, 2022. Early adoption is permitted. We are currently assessing the potential impact of adopting ASU 2016-02 on our financial statements and financial statement disclosures. In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments . ASU 2016-13 requires measurement and recognition of expected credit losses for financial assets. In April 2019, the FASB issued clarification to ASU 2016-13 within ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivatives and Hedging , and Topic 825, Financial Instruments , or ASU 2016-13. The guidance is effective for fiscal years beginning after December 15, 2022. We are currently assessing the potential impact of adopting ASU 2016-13 on our financial statements and financial statement disclosures. In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes , or ASU 2019-12. ASU 2019-12 eliminates certain exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also clarifies and simplifies other aspects of the accounting for income taxes. This guidance is effective for fiscal years beginning after December 15, 2021, and interim periods within fiscal years beginning after December 15, 2022. Early adoption is permitted. We are currently assessing the impact adoption of ASU 2019-12 will have on our financial statements and disclosures. In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging Contracts in Entity s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity . ASU 2020-06 will simplify the accounting for convertible instruments by reducing the number of accounting models for convertible debt instruments and convertible preferred stock. Limiting the accounting models results in fewer embedded conversion features being separately recognized from the host contract as compared with current GAAP. Convertible instruments that continue to be subject to separation models are (i) those with embedded conversion features that are not clearly and closely related to the host contract, that meet the definition of a derivative, and that do not qualify for a scope exception from derivative accounting and (ii) convertible debt instruments issued with substantial premiums for which the premiums are recorded as paid-in capital. ASU 2020-06 also amends the guidance for the derivatives scope exception for contracts in an entity’s own equity to reduce form-over-substance-based accounting conclusions. ASU 2020-06 will be effective for us beginning after December 15, 2023. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. We are currently assessing the impact adoption of ASU 2020-06 will have on our financial statements and disclosures.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The following table presents information about our financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values (in thousands): September 30, 2021 Total Level 1 Level 2 Level 3 Current liabilities Preference shares tranche obligations $ 28,276 $ — $ — $ 28,276 Total financial liabilities measured at fair value $ 28,276 $ — $ — $ 28,276 The following table presents a roll-forward of the fair value of the convertible note and preference shares tranche obligations for which fair value is determined by Level 3 inputs (in thousands): Preference Convertible Total Balance, January 1, 2020 $ — $ 8,663 $ 8,663 Fair value adjustments — 1,985 1,985 Currency exchange — ( 375 ) ( 375 ) Conversion into class B preference shares — ( 10,273 ) ( 10,273 ) Balance, December 31, 2020 — — — Addition on issuance of class C preference shares 2,425 — 2,425 Fair value adjustments 26,830 — 26,830 Currency exchange ( 979 ) — ( 979 ) Balance, September 30, 2021 $ 28,276 $ — $ 28,276 Valuation techniques used to measure fair value maximize the use of relevant observable inputs and minimize the use of unobservable inputs. Our convertible notes were classified within Level 3 of the fair value hierarchy because the fair value measurement was based, in part, on significant inputs not observed in the market. In July 2019, we issued convertible notes to existing related party investors for proceeds of $ 9.0 million. Upon issuance, we elected the fair value option to account for the convertible notes, with any subsequent changes in fair value being recognized through the statements of operations as other income (expense) until the convertible notes are settled. We have not recorded interest expense separate from those fair value adjustments. The convertible notes accrued interest at 8 % per year beginning in August 2019 payable in cash or, at the investor’s discretion, into our class B or class C preference shares. In April 2020, the convertible notes plus accrued interest of $ 0.5 million, were converted according to the terms of the convertible notes into 142,437 shares of class B preference shares (Note 8). On conversion in April 2020, we determined the fair value of the convertible notes with reference to the class B preference shares (Note 8) into which the convertible notes were converted. Our class C Preference Shares Tranche Obligation is measured at fair value using a Black-Scholes option pricing valuation methodology. The fair value of class C Preference Shares Tranche Obligation includes inputs not observable in the market and thus represents a Level 3 measurement. The option pricing valuation methodology utilized requires inputs based on certain subjective assumptions, including (i) expected stock price volatility, (ii) calculation of an expected term, (iii) a risk-free interest rate, and (iv) expected dividends. The assumptions utilized to value the class C Preference Shares Tranche Obligation as of September 30, 2021 were (i) expected stock price volatility of 73.7 %; (ii) remaining term of 0.3 years; (iii) a risk-free interest rate of 0.05 %; and (iv) an expectation of no dividends. There were no transfers among Level 1, Level 2 or Level 3 categories in the nine months ended September 30, 2021 and year ended December 31, 2020.

License and Collaboration Agree

License and Collaboration Agreements	9 Months Ended
	Sep. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
License and Collaboration Agreements	4. License and Collaboration Agreements In February 2018, we entered into a clinical collaboration with MSD International GmbH, or MSD, to evaluate IO102 in combination with KEYTRUDA ® (pembrolizumab) in first-line treatment of patients with metastatic non-small cell lung cancer. Under the terms of the collaboration with MSD, we will conduct an international Phase 1/2 study to evaluate a combination therapy of IO102 and KEYTRUDA ® . We will sponsor the clinical trials and MSD will provide KEYTRUDA ® to be used in the clinical trials free of charge. We and MSD will be responsible for our own internal costs and expenses to support the study and we shall bear all other costs associated with conducting the study, including costs of providing IO102 for use in the study. The rights to the data from the clinical trials will be shared by us and MSD and we will maintain global commercial rights to IO102. In September 2021, we entered into a clinical collaboration with MSD to evaluate IO102-IO103 in combination with KEYTRUDA ® versus KEYTRUDA ® alone in treatment of patients with metastatic (advanced) melanoma. Under the terms of the collaboration with MSD, we will conduct an international Phase 3 study to evaluate a combination therapy of IO102-IO103 and KEYTRUDA ® . We will sponsor the clinical trials and MSD will provide KEYTRUDA ® to be used in the clinical trials free of charge. We and MSD will be responsible for our own internal costs and expenses to support the study and we shall bear all other costs associated with conducting the study, including costs of providing IO102-IO103 for use in the study. The rights to the data from the clinical trials will be shared by us and MSD and we will maintain global commercial rights to IO102-IO103.

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	9 Months Ended
	Sep. 30, 2021
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Current Assets	5. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of the following (in thousands): September 30, December 31, Prepaid contract research and development costs $ 1,622 $ 359 Research and development tax credit receivable 1,712 904 Value-added tax refund receivable 407 596 Deferred offering costs 2,413 — Other 362 371 Total prepaid expenses and other current assets $ 6,516 $ 2,230

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	9 Months Ended
	Sep. 30, 2021
Payables And Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following (in thousands): September 30, December 31, Accrued contract research and development costs $ 1,011 $ 1,487 Employee compensation costs 538 785 Professional fees 1,445 9 Other liabilities 350 247 Total accrued expenses and other current liabilities $ 3,344 $ 2,528

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies Lease Commitments We have two operating leases in Copenhagen, Denmark for office space that expire in August 2021 and December 2021 , respectively. In March 2021, we entered into a new lease for our office space in Copenhagen, Denmark that expires in January 2025 , terminable upon three months’ notice. Rent expense for the nine months ended September 30, 2021 and 2020 was $ 210,000 and $ 147,000 respectively, and for the three months ended September 30, 2021 and 2020 was $ 81,000 and $ 64,000 , respectively. Legal Proceedings From time to time, we may be party to litigation arising in the ordinary course of its business. We were not subject to any material legal proceedings during the nine months ended September 30, 2021 and year ended December 31, 2020, and, to our knowledge, no material legal proceedings are currently pending or threatened. Research Agreements The Company and the Herlev University Hospital in Denmark (“Herlev”) have a number of existing agreements for scientific and other support of the Company’s ongoing development activities. In January 2021, the Company entered into an additional agreement with Herlev regarding the payment of specific services whereupon in addition to any consideration payable by the Company to Herlev pursuant to the existing agreements the Company shall pay a fee to Herlev of DKK 5.0 million (approximately $ 0.8 million) in the event of an initial public offering or other liquidity event whereby all or substantially all of the value of the Company is realized in consideration for cash. The Company consummated its IPO in November 2021, resulting in this payment to Herlev becoming payable. Additionally, upon the completion of the IPO, the Company is obligated to make payments to Herlev in the aggregate amount of DKK 13.6 million, (which is approximately $ 2.1 million based on the exchange rate of DKK 6.43 to one U.S. dollar on September 30, 2021) including the DKK 5.0 million previously mentioned. Indemnification Agreements We enter into certain types of contracts that contingently requires us to indemnify various parties against claims from third parties. These contracts primarily relate to procurement, service, consultancy or license agreements under which we may be required to indemnify vendors, service providers or licensees for certain claims, including claims that may be brought against them arising from our acts or omissions with respect to our products, technology, intellectual property or services. From time to time, we may receive indemnification claims under these contracts in the normal course of business. In the event that one or more of these matters were to result in a claim against us, an adverse outcome, including a judgment or settlement, may cause a material adverse effect on our future business, operating results or financial condition. It is not possible to estimate the maximum amount potentially payable under these contracts since we have no history of prior indemnification claims and the unique facts and circumstances involved in each particular claim will be determinative.

Convertible Preference Shares

Convertible Preference Shares	9 Months Ended
	Sep. 30, 2021
Temporary Equity Disclosure [Abstract]
Convertible Preference Shares	8. Convertible Preference Shares As of September 30, 2021 and December 31, 2020 , we had 584,583 class B preference shares authorized, issued and outstanding. As of September 30, 2021 , we had 1,263,804 class C preference shares authorized and 538,088 class C preference shares issued and outstanding. In April 2020, we issued 142,437 class B preference shares at a subscription price of $ 64.48 per share to existing related-party investors upon the conversion of convertible notes (Note 3). We recorded the 142,437 class B preference shares at fair value of $ 10.3 million ($ 72.15 per share) determined using an option pricing model, or OPM, assuming a Company equity value of $ 40.6 million, a term of 1.6 years, volatility of 86.0 % and a risk-free rate of 0.18 %. We incurred issuance costs of $ 4,000 in connection with the issuances of the class B preference shares on conversion of the convertible notes. In July 2020, we issued 75,845 class B preference shares to existing related-party investors at a subscription price of $ 67.46 per share for gross cash proceeds of $ 5.1 million. We recorded the 75,845 class B preference shares at fair value of $ 5.6 million ($ 73.60 per share), resulting in a deemed dividend of $ 0.5 million recorded against additional paid-in capital on our balance sheet. Fair value of the class B preference shares issued on this date was determined using an OPM methodology assuming a Company equity value of $ 47.6 million, a term of 1.36 years, volatility of 92.4 % and a risk-free rate of 0.16 %. We incurred issuance costs of $ 10,000 in connection with the issuances of the class B preference shares. In January 2021, we completed an investment agreement, Class C Investment Agreement, for the sale and issuance of up to 1,263,804 class C preference shares to new investors and existing related-party investors at a subscription price of $ 121.55 per share. Then, pursuant to the Class C Investment Agreement, we issued 505,520 class C preference shares for gross cash proceeds of $ 61.5 million. The Class C Investment Agreement further provides for a milestone closing in the event of certain development milestones before April 2022, whereby purchasers of class C preference shares are obligated to a further subscription amount of $ 88.4 million, or the Preference Shares Tranche Obligation, which resulted in a further issuance of 689,344 class C preference shares at a subscription price of $ 128.19 per share. We incurred issuance costs of $ 340,000 in connection with the issuances of the class C preference shares. We concluded that the Preference Shares Tranche Obligation met the definition of a freestanding financial instrument, as it is legally detachable and separately exercisable from the class C preference shares. Therefore, we allocated the proceeds received from the issuance of shares under the Class C Investment Agreement between the Preference Shares Tranche Obligation and the class C preference shares. The fair value of the Preference Shares Tranche Obligation of $ 2.4 million on issuance was allocated from the $ 61.5 million proceeds of the class C preference shares financing and is classified as a current liability on the balance sheet as of September 30, 2021 as the class C preference shares would become redeemable upon a Deemed Liquidation Event, the occurrence of which is not within our control. In March 2021, prior to a milestone closing, an investor elected to purchase and we issued 35,825 class C preference shares for gross cash proceeds of $ 4.2 million pursuant to the Class C Investment Agreement. As a result of entering into a collaboration agreement with Merck in September 2021, the number of class C preference shares issued in March 2021 was adjusted downward to 32,568 class C preference shares. In October 2021, investors purchased and we issued 656,776 class C preference shares for gross cash proceeds of $ 84.1 million pursuant to the Class C Investment Agreement. Preferences, Privileges and Rights Our class C preference shares and our class B preference shares together constitute our preferred classes of stock, or Preference Shares. Our Preference Shares have the following rights, preferences, privileges and restrictions: Liquidity Preference Company liquidity events, or Liquidity Events, include assignment or transfer of all or part of the shares from our shareholders as a whole, listing of our shares, merger, demerger, liquidation or other dissolution of the Company, payment of dividends, reduction of our share capital for distribution to shareholders. In the case of a Liquidity Event, cash and property proceeds shall be distributed to our shareholders in accordance with the following priority: (i) First, the holders of class C preference shares, in preference to holders of class B preference shares and class A ordinary shares, the subscription price paid and 8 % per year interest on the subscription price paid from the date of payment of the subscription price until the date of allocation of proceeds, provided that where the available proceeds are insufficient to make payment in full on the class C preference shares, then the available proceeds shall be allocated pro rata among the holders in proportion to their holdings of class C preference shares; (ii) Second, the holders of class B preference in preference to holders of class A ordinary shares, on any proceeds remaining after payment of proceeds to the holders of class C preference shares the subscription price paid and 8 % per year interest on the subscription price paid from the date of payment of the subscription price until the date of allocation of proceeds, provided that where the available proceeds are insufficient to make payment in full on the class B preference shares, then the available proceeds shall be allocated pro rata among the holders in proportion to their holdings of class B preference shares. Distribution preferences pursuant to (i) and (ii) above, together the Liquidity Preference. Conversion Option Our Preference Shares are convertible at the option of the holder at any time on a one-for-one basis into our class A ordinary shares. Voting Rights and Board Representation The holders of Preference Shares are entitled to one vote per share on all matters to be voted upon at all shareholder meetings and written actions in lieu of meetings. The holders of Preference Shares are entitled to elect six of the eight directors on our board. Anti-Dilution Protection In the event we issue any additional shares for a consideration per share that is less than the applicable subscription price paid for the Preference Shares, the subscription price of the applicable Preference Shares (as adjusted for share splits, payment of dividends, recapitalization, consolidations of shares and similar events) for existing shareholders who participate in the purchase of such additional shares shall be adjusted on a weighted average basis. The adjustment shall be made through the issuance of new Preference Shares of the relevant class to the Preference Shareholders at quota value. Redemption Preference Shares are not subject to mandatory redemption. Upon certain change in control events that are outside of our control, including liquidation, sale or transfer of control of the Company, the Preference Shares are contingently redeemable.

Ordinary Shares

Ordinary Shares	9 Months Ended
	Sep. 30, 2021
Class Of Stock Disclosures [Abstract]
Ordinary Shares	9. Ordinary Shares As of September 30, 2021 and December 31, 2020 , we had 177,200 shares of class A ordinary shares authorized, issued and outstanding. The holders of class A ordinary shares are entitled to an allocation and distribution of proceeds in a Liquidity Event subject to the Liquidation Preference. When the Liquidity Preference has been paid in full, any remaining proceeds shall be allocated pro rata to all shares in the Company. The holders of class A ordinary shares are entitled to one vote per share on all matters to be voted upon at all shareholder meetings and written actions in lieu of meetings. Together, as a single class with holders of Preference Shares, holders of class A ordinary shares may appoint two independent directors of our board.

Equity-Based Compensation

Equity-Based Compensation	9 Months Ended
	Sep. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity-Based Compensation	10. Equity-Based Compensation Employee Equity Plan We may award up to 1,187,272 warrants. Each vested warrant will entitle the warrant holder to a single class A ordinary share. Holders of stock warrants are entitled to exercise the vested portion of the stock warrant. Stock warrants generally vest over a three-year period and expire five years from the vest date. At September 30, 2021 , we had 402,024 warrants available for future grant under our employee equity plan. There were no grants, exercises, or forfeitures of any stock warrants during the nine months ended September 30, 2020 . We issued 695,313 warrants with an exercise price of $ 19.62 to certain employees, board members and advisors during the nine months ended September 30, 2021. The following table summarizes our stock warrants activity: Number of Weighted- Weighted- Aggregate Outstanding December 31, 2019 89,935 $ 15.00 5.6 $ — Outstanding December 31, 2020 89,935 $ 15.00 4.6 $ — Granted 695,313 $ 19.62 Outstanding September 30, 2021 785,248 $ 19.09 8.1 $ — Exercisable at September 30, 2021 120,920 $ 16.24 4.4 $ — Equity-Based Compensation All share-based awards granted are measured based on the fair value on the date of the grant and compensation expense is recognized with respect to those awards over the requisite service period, which is generally the vesting period of the respective award. Forfeitures related to equity-based compensation awards are recognized as they occur, and we reverse any previously recognized compensation cost associated with forfeited awards in the period the forfeiture occurs. As of September 30, 2021, there was $ 5.3 million of unrecognized compensation cost related to unvested stock-based compensation arrangements that is expected to be recognized over a weighted average period of 3.6 years. Equity-based compensation expense recorded as research and development and general and administrative expenses is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Research and development $ 163 $ 5 $ 166 $ 16 General and administrative 320 11 326 32 Total equity-based compensation $ 483 $ 16 $ 492 $ 48

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes We are subject to taxes for earnings generated in Denmark and our tax expense is primarily affected by unrecognized tax benefits in Denmark. We did no t record a provision or benefit for income taxes during the nine months ended September 30, 2021 and 2020. We continue to maintain a full valuation allowance against all of our deferred tax assets. We have evaluated the positive and negative evidence involving our ability to realize our deferred tax assets. We have considered our history of cumulative net losses incurred since inception and our lack of any commercial products. We have concluded that it is more likely than not that we will not realize the benefits of our deferred tax assets. We reevaluate the positive and negative evidence at each reporting period.

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Loss Per Share	12. Net Loss Per Share Basic and diluted net loss per ordinary share is calculated as follows (in thousands except share and per share amounts): For the Three Months Nine Months Ended 2021 2020 2021 2020 Net loss $ ( 4,462 ) $ ( 3,488 ) $ ( 46,570 ) $ ( 9,488 ) Cumulative dividends on class B and C preference shares ( 2,073 ) ( 661 ) ( 6,006 ) ( 1,683 ) Net loss attributable to class A ordinary shareholders $ ( 6,535 ) $ ( 4,149 ) $ ( 52,576 ) $ ( 11,171 ) Net loss per class A ordinary share, basic and diluted $ ( 36.88 ) $ ( 23.41 ) $ ( 296.70 ) $ ( 63.04 ) Weighted-average number of shares used in computing net loss per class A ordinary shares, basic and diluted 177,200 177,200 177,200 177,200 The following outstanding potentially dilutive securities have been excluded from the calculation of diluted net loss per class A ordinary share, as their effect is anti-dilutive: Three Months Ended Nine Months Ended 2021 2020 2021 2020 Convertible preference shares 1,122,671 584,583 1,122,671 584,583 Stock warrants to purchase class A ordinary shares 785,248 89,935 785,248 89,935

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events Stock Split Our board of directors and shareholders approved a 3.544 -for-1 stock split of the issued and outstanding class A ordinary shares and a proportional adjustment to the existing conversion ratios for the preference shares effective as of November 1, 2021. Accordingly, all share and per share amounts for all periods presented in the accompanying financial statements and notes thereto have been retroactively adjusted, where applicable, to reflect the stock split. 2021 Equity Incentive Plan In November 2021, in anticipation of the IPO, our board of directors adopted and our stockholders approved the 2021 Equity Incentive Plan (or the “2021 Plan”), which became effective on November 4, 2021. The 2021 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, awards of restricted stock, restricted stock units and other stock-based awards. The number of shares of our common stock reserved for issuance under the 2021 Plan is equal to 2,465,150 , subject to an annual increase, to be added on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2022 and continuing until, and including, the fiscal year ending December 31, 2031, equal to the lesser of (i) 4 % of the number of shares of common stock outstanding on the first day of such fiscal year or (ii) such other amount determined by our board of directors . 2021 Employee Stock Purchase Plan In November 2021, in anticipation of the IPO, our board of directors adopted and our stockholders approved the 2021 Employee Stock Purchase Plan (or the “2021 ESPP”), which became effective on November 4, 2021. The number of shares of our common stock reserved for issuance under the 2021 ESPP is equal to 257,272 , subject to an annual increase, to be added on the first day of each fiscal year, beginning January 1, 2023, equal to the lesser of (i) 1 % of the number of shares of common stock outstanding on the first day of such fiscal year, (ii) 257,272 shares of our common stock or (iii) such other amount determined by our board of directors . Initial Public Offering In November 2021, we completed our IPO, selling an aggregate of 8,222,500 shares of common stock at a price to the public of $ 14.00 per share, including 1,072,500 shares of common stock sold pursuant to the underwriters’ exercise of their option to purchase additional shares of common stock. We received net proceeds from the IPO, after deducting underwriting discounts and commissions but before deducting offering costs, of approximately $ 103.3 million. Immediately prior to the consummation of the IPO, all outstanding shares of our class A ordinary shares and class B and class C convertible preference shares were converted into 20,592,413 shares of common stock. Upon the closing of the IPO on November 9, 2021, a total of 28,815,267 shares of common stock were outstanding. Our common stock began trading on the Nasdaq Global Market on November 5, 2021 under the symbol “IOBT”. On November 9, 2021, we amended and restated the certificate of incorporation of IO Biotech, Inc. to authorize 300,000,000 shares of common stock and 5,000,000 shares of preferred stock, which shares of preferred stock are currently undesignated. Equity-based compensation In October 2021, our Board of directors granted a total of 1,611,174 warrants to purchase class A ordinary shares to employees, directors and consultants with an exercise price of $ 12.64 .

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Principles of Consolidation	Principles of consolidation The Company’s condensed consolidated financial statements include the accounts of its subsidiaries IO Bio US, Inc. and IO Biotech Limited. IO Bio US, Inc., a wholly owned subsidiary of IO Biotech ApS, was incorporated in Delaware in May 2021. IO Biotech Limited, a wholly owned subsidiary of IO Biotech ApS, was incorporated in the UK in August 2021. In October 2021, the Company engaged in a series of transactions, referred to collectively as the Corporate Reorganization. As a result of the Corporate Reorganization, IO Biotech ApS became a wholly-owned subsidiary of IO Biotech, Inc. and accordingly, our consolidated financial statements will be those of IO Biotech, Inc. for the periods after the date of the Corporate Reorganization. IO Biotech, Inc. is a recently formed holding company, which, prior to our IPO, had nominal assets and no liabilities, contingencies, or commitments, and which has not conducted any operations prior to our IPO other than acquiring the entire issued and outstanding stock of IO Biotech ApS. The Company, IO Biotech ApS, and the holders of all of the issued and outstanding equity interests of IO Biotech ApS have entered into a Share Contribution and Exchange Agreement, dated as of October 29, 2021, pursuant to which the Corporate Reorganization was effected.
Unaudited Financial Information	Unaudited Financial Information The Company’s condensed financial statements included herein have been prepared in conformity with accounting principles generally accepted in the United States of America, or GAAP, and pursuant to the rules and regulations of the Securities and Exchange Commission, or SEC. In the Company’s opinion, the information furnished reflects all adjustments, all of which are of a normal and recurring nature, necessary for a fair presentation of the financial position and results of operations for the reported interim periods. The Company consider events or transactions that occur after the balance sheet date but before the financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year or any other interim period.
Restatement of Prior Period Financial Statements.	Restatement of Prior Period Financial Statements. In connection with the preparation of our consolidated financial statements, we identified an error related to the recording of an accrued expense as of June 30, 2021, which led to the overstatement of research and development expenses for the six months ended June 30, 2021. As previously disclosed in our Current Report on Form 8-K filed on December 17, 2021, we have restated our previously reported Unaudited Interim Condensed Financial Statements as of June 30, 2021 and for the Six Months Ended June 30, 2021 and 2020 for this error.
Recently Issued Accounting Standards	Recently Issued Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) , as amended, with guidance regarding the accounting for and disclosure of leases. ASU 2016-02 requires lessees to recognize the liabilities related all leases, including operating leases, with a term greater than 12 months on the balance sheet. This update also requires lessees and lessors to disclose key information about their leasing transactions. This standard is effective for annual reporting periods beginning after December 15, 2021, and interim periods within annual periods beginning after December 15, 2022. Early adoption is permitted. We are currently assessing the potential impact of adopting ASU 2016-02 on our financial statements and financial statement disclosures. In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments . ASU 2016-13 requires measurement and recognition of expected credit losses for financial assets. In April 2019, the FASB issued clarification to ASU 2016-13 within ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivatives and Hedging , and Topic 825, Financial Instruments , or ASU 2016-13. The guidance is effective for fiscal years beginning after December 15, 2022. We are currently assessing the potential impact of adopting ASU 2016-13 on our financial statements and financial statement disclosures. In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes , or ASU 2019-12. ASU 2019-12 eliminates certain exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also clarifies and simplifies other aspects of the accounting for income taxes. This guidance is effective for fiscal years beginning after December 15, 2021, and interim periods within fiscal years beginning after December 15, 2022. Early adoption is permitted. We are currently assessing the impact adoption of ASU 2019-12 will have on our financial statements and disclosures. In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging Contracts in Entity s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity . ASU 2020-06 will simplify the accounting for convertible instruments by reducing the number of accounting models for convertible debt instruments and convertible preferred stock. Limiting the accounting models results in fewer embedded conversion features being separately recognized from the host contract as compared with current GAAP. Convertible instruments that continue to be subject to separation models are (i) those with embedded conversion features that are not clearly and closely related to the host contract, that meet the definition of a derivative, and that do not qualify for a scope exception from derivative accounting and (ii) convertible debt instruments issued with substantial premiums for which the premiums are recorded as paid-in capital. ASU 2020-06 also amends the guidance for the derivatives scope exception for contracts in an entity’s own equity to reduce form-over-substance-based accounting conclusions. ASU 2020-06 will be effective for us beginning after December 15, 2023. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. We are currently assessing the impact adoption of ASU 2020-06 will have on our financial statements and disclosures.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table presents information about our financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values (in thousands): September 30, 2021 Total Level 1 Level 2 Level 3 Current liabilities Preference shares tranche obligations $ 28,276 $ — $ — $ 28,276 Total financial liabilities measured at fair value $ 28,276 $ — $ — $ 28,276
Roll-forward of Fair Value of Convertible Note and Preference Shares Tranche Obligations for Which Fair Value Determined by Level 3 Inputs	The following table presents a roll-forward of the fair value of the convertible note and preference shares tranche obligations for which fair value is determined by Level 3 inputs (in thousands): Preference Convertible Total Balance, January 1, 2020 $ — $ 8,663 $ 8,663 Fair value adjustments — 1,985 1,985 Currency exchange — ( 375 ) ( 375 ) Conversion into class B preference shares — ( 10,273 ) ( 10,273 ) Balance, December 31, 2020 — — — Addition on issuance of class C preference shares 2,425 — 2,425 Fair value adjustments 26,830 — 26,830 Currency exchange ( 979 ) — ( 979 ) Balance, September 30, 2021 $ 28,276 $ — $ 28,276

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	9 Months Ended
	Sep. 30, 2021
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Summary of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consist of the following (in thousands): September 30, December 31, Prepaid contract research and development costs $ 1,622 $ 359 Research and development tax credit receivable 1,712 904 Value-added tax refund receivable 407 596 Deferred offering costs 2,413 — Other 362 371 Total prepaid expenses and other current assets $ 6,516 $ 2,230

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2021
Payables And Accruals [Abstract]
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): September 30, December 31, Accrued contract research and development costs $ 1,011 $ 1,487 Employee compensation costs 538 785 Professional fees 1,445 9 Other liabilities 350 247 Total accrued expenses and other current liabilities $ 3,344 $ 2,528

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Stock Warrants Activity	The following table summarizes our stock warrants activity: Number of Weighted- Weighted- Aggregate Outstanding December 31, 2019 89,935 $ 15.00 5.6 $ — Outstanding December 31, 2020 89,935 $ 15.00 4.6 $ — Granted 695,313 $ 19.62 Outstanding September 30, 2021 785,248 $ 19.09 8.1 $ — Exercisable at September 30, 2021 120,920 $ 16.24 4.4 $ —
Schedule of Equity-based Compensation Expense	Equity-based compensation expense recorded as research and development and general and administrative expenses is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Research and development $ 163 $ 5 $ 166 $ 16 General and administrative 320 11 326 32 Total equity-based compensation $ 483 $ 16 $ 492 $ 48

Net Loss Per Share (Table)

Net Loss Per Share (Table)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	Basic and diluted net loss per ordinary share is calculated as follows (in thousands except share and per share amounts): For the Three Months Nine Months Ended 2021 2020 2021 2020 Net loss $ ( 4,462 ) $ ( 3,488 ) $ ( 46,570 ) $ ( 9,488 ) Cumulative dividends on class B and C preference shares ( 2,073 ) ( 661 ) ( 6,006 ) ( 1,683 ) Net loss attributable to class A ordinary shareholders $ ( 6,535 ) $ ( 4,149 ) $ ( 52,576 ) $ ( 11,171 ) Net loss per class A ordinary share, basic and diluted $ ( 36.88 ) $ ( 23.41 ) $ ( 296.70 ) $ ( 63.04 ) Weighted-average number of shares used in computing net loss per class A ordinary shares, basic and diluted 177,200 177,200 177,200 177,200
Schedule of Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss per Share	The following outstanding potentially dilutive securities have been excluded from the calculation of diluted net loss per class A ordinary share, as their effect is anti-dilutive: Three Months Ended Nine Months Ended 2021 2020 2021 2020 Convertible preference shares 1,122,671 584,583 1,122,671 584,583 Stock warrants to purchase class A ordinary shares 785,248 89,935 785,248 89,935

Description of Business, Orga_2

Description of Business, Organization and Liquidity - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended
	Nov. 30, 2021	Oct. 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Mar. 31, 2021	Jan. 31, 2021
Description Of Business Organization And Liquidity [Line Items]
Accumulated deficit			$ (84,972)		$ (84,972)		$ (38,402)
Net losses			(4,462)	$ (3,488)	(46,570)	$ (9,488)	(12,000)
Cash and cash equivalents			$ 45,477		45,477		$ 3,405
Gross cash proceeds from issuance of convertible preferred stock					$ 65,748	$ 5,116
Subsequent Events
Description Of Business Organization And Liquidity [Line Items]
Net proceeds from IPO, after deducting underwriting discounts, commissions and offering costs	$ 103,300
Class C Preference Shares
Description Of Business Organization And Liquidity [Line Items]
Convertible preference shares, shares issued								35,825	505,520
Class C Preference Shares | Subsequent Events
Description Of Business Organization And Liquidity [Line Items]
Gross cash proceeds from issuance of convertible preferred stock		$ 84,100
Convertible preference shares, shares issued		656,776
Underwriters | Subsequent Events
Description Of Business Organization And Liquidity [Line Items]
Shares issued	1,072,500

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Recurring $ in Thousands	Sep. 30, 2021USD ($)
Current liabilities
Preference shares tranche obligations	$ 28,276
Total financial liabilities measured at fair value	28,276
Level 3
Current liabilities
Preference shares tranche obligations	28,276
Total financial liabilities measured at fair value	$ 28,276

Fair Value Measurements - Roll-

Fair Value Measurements - Roll-forward of Fair Value of Convertible Note and Preference Shares Tranche Obligations for Which Fair Value Determined by Level 3 Inputs (Details) - Level 3 - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Beginning balance		$ 8,663
Addition on issuance of class C preference shares	$ 2,425
Fair value adjustments	26,830	1,985
Currency exchange	(979)	(375)
Conversion into class B preference shares		(10,273)
Ending balance	28,276
Preference Shares Tranche Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Addition on issuance of class C preference shares	2,425
Fair value adjustments	26,830
Currency exchange	(979)
Ending balance	$ 28,276
Convertible Note
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Beginning balance		8,663
Fair value adjustments		1,985
Currency exchange		(375)
Conversion into class B preference shares		$ (10,273)

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details)	1 Months Ended		9 Months Ended	12 Months Ended
	Apr. 30, 2020USD ($)shares	Jul. 31, 2019USD ($)	Sep. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Proceeds from issuance of convertible notes		$ 9,000,000
Convertible notes converted	$ 500,000
Transfers from Level 1 to Level 2			$ 0	$ 0
Transfers from Level 2 to Level 1			0	0
Transfers into Level 3			0	0
Transfers out of Level 3			$ 0	$ 0
Convertible Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Convertible notes interest rate	8.00%
Class B Preference Shares
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number of preferred stock shares upon conversion | shares	142,437
Class C Convertible Preference Stock | Expected Stock Price Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Preference stock measurement input			0.737
Class C Convertible Preference Stock | Remaining Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Remaining term			3 months 18 days
Class C Convertible Preference Stock | Risk-Free Interest Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Preference stock measurement input			0.05
Class C Convertible Preference Stock | Expectation of Dividends
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Preference stock measurement input			0

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets - Summary of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid contract research and development costs	$ 1,622	$ 359
Research and development tax credit receivable	1,712	904
Value-added tax refund receivable	407	596
Deferred offering costs	2,413
Other	362	371
Total prepaid expenses and other current assets	$ 6,516	$ 2,230

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Accrued contract research and development costs	$ 1,011	$ 1,487
Employee compensation costs	538	785
Professional fees	1,445	9
Other liabilities	350	247
Total accrued expenses and other current liabilities	$ 3,344	$ 2,528

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) kr in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 31, 2021	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)Lease	Sep. 30, 2020USD ($)	Sep. 30, 2021DKK (kr)	Jan. 31, 2021USD ($)	Jan. 31, 2021DKK (kr)
Commitments And Contingencies Disclosure [Abstract]
Number of operating leases | Lease				2
Operating lease expiration period one				2021-08
Operating lease expiration period two				2021-12
Operating new lease expiration period	2025-01
Lessee, operating lease, option to terminate				In March 2021, we entered into a new lease for our office space in Copenhagen, Denmark that expires in January 2025, terminable upon three months’ notice.
Rent expense | $		$ 81,000	$ 64,000	$ 210,000	$ 147,000
Fee payable for specific services							$ 800,000	kr 5
Aggregate amount obligated to pay under research agreements		$ 2,100,000		$ 2,100,000		kr 13.6
Exchange rate of DKK to one U.S. dollar		6.43		6.43		6.43

Convertible Preference Shares -

Convertible Preference Shares - Additional information (Details)	1 Months Ended					9 Months Ended
	Oct. 31, 2021USD ($)shares	Mar. 31, 2021USD ($)shares	Jan. 31, 2021USD ($)$ / sharesshares	Jul. 31, 2020USD ($)$ / sharesshares	Apr. 30, 2020USD ($)$ / sharesshares	Sep. 30, 2021USD ($)DirectorVoteshares	Dec. 31, 2020shares
Class Of Stock [Line Items]
Preferred stock, conversion basis						one-for-one basis into our class A ordinary shares.
Number of votes per share | Vote						1
Number of directors on board | Director						8
Number of directors entitled to be elected by preference shareholders | Director						6
Class B Preference Shares
Class Of Stock [Line Items]
Preference shares authorized | shares						584,583	584,583
Preference shares issued | shares					142,437	584,583	584,583
Preference shares outstanding | shares						584,583	584,583
Preference share per share | $ / shares					$ 64.48
Fair value of shares issued					$ 10,300,000
Shares issued fair value per share | $ / shares					$ 72.15
Convertible preference shares, shares issued | shares				75,845
Temporary equity, subscription price per share | $ / shares				$ 67.46
Proceeds from issuance of preference shares				$ 5,100,000
Temporary equity, Issuance of preference shares, net of issuance costs				$ 5,600,000
Temporary equity, share price | $ / shares				$ 73.60
Deemed dividend				$ 500,000
Temporary equity, issuance costs				10,000
Percentage of interest on subscription price						8.00%
Class B Preference Shares | Option Pricing Model
Class Of Stock [Line Items]
Convertible notes equity value					$ 40,600,000
Convertible notes term					1 year 7 months 6 days
Convertible notes volatility percentage					86.00%
Convertible notes risk free rate					0.18%
Convertible notes conversion cost					$ 4,000,000
Equity, fair value assumed				$ 47,600,000
Equity securities term				1 year 4 months 9 days
Class B Preference Shares | Option Pricing Model | Expected Stock Price Volatility
Class Of Stock [Line Items]
Equity securities, measurement input				92.4
Class B Preference Shares | Option Pricing Model | Risk-Free Interest Rate
Class Of Stock [Line Items]
Equity securities, measurement input				0.16
Class C Preference Shares
Class Of Stock [Line Items]
Preference shares authorized | shares						1,263,804
Preference shares issued | shares						538,088
Preference shares outstanding | shares						538,088
Convertible preference shares, shares issued | shares		35,825	505,520
Temporary equity, subscription price per share | $ / shares			$ 121.55
Proceeds from issuance of preference shares		$ 4,200,000	$ 61,500,000
Temporary equity, issuance costs			$ 340,000
Convertible preference shares, shares authorized | shares			1,263,804
Number of shares issued for adjusted downward | shares		32,568
Percentage of interest on subscription price						8.00%
Class C Preference Shares | Subsequent Events
Class Of Stock [Line Items]
Convertible preference shares, shares issued | shares	656,776
Proceeds from issuance of preference shares	$ 84,100,000
Class C Preference Shares | Tranche Obligation
Class Of Stock [Line Items]
Convertible preference shares, shares issued | shares			689,344
Temporary equity, subscription price per share | $ / shares			$ 128.19
Proceeds from issuance of preference shares						$ 61,500,000
Temporary equity, subscription amount			$ 88,400,000
Fair value of preference shares tranche obligation						$ 2,400,000

Ordinary Shares - Additional In

Ordinary Shares - Additional Information (Details)	Sep. 30, 2021Voteshares	Dec. 31, 2020shares
Class Of Stock [Line Items]
Number of votes per share | Vote	1
Class A Ordinary Shares
Class Of Stock [Line Items]
Ordinary shares, shares authorized	177,200	177,200
Ordinary shares, shares issued	177,200	177,200
Ordinary shares, shares outstanding	177,200	177,200
Number of votes per share | Vote	1

Equity-Based Compensation - Add

Equity-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost	$ 5.3
Unrecognized compensation cost, recognition period	3 years 7 months 6 days
Employee Equity Plan | Stock Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	3 years
Expiration period from vest date	5 years
Number of warrants available for future grant	402,024
Number of warrants issued/granted	695,313	0
Warrants, exercise price	$ 19.62
Number of warrants, exercised		0
Number of warrants, forfeitures		0
Employee Equity Plan | Stock Warrants | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of warrants	1,187,272

Equity-Based Compensation - Sch

Equity-Based Compensation - Schedule of Stock Warrants Activity (Details) - Warrant - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Warrants, Beginning balance	89,935	89,935
Number of Warrants, Granted	695,313
Number of Warrants, Ending balance	785,248	89,935	89,935
Number of Warrants, Exercisable	120,920
Weighted-average exercise price per share, Beginning balance	$ 15	$ 15
Weighted-average exercise price per share, Granted	19.62
Weighted-average exercise price per share, Ending balance	19.09	$ 15	$ 15
Weighted-average exercise price per share, Exercisable	$ 16.24
Weighted-average remaining contractual term (in years), Outstanding	8 years 1 month 6 days	4 years 7 months 6 days	5 years 7 months 6 days
Weighted-average remaining contractual term (in years), Exercisable	4 years 4 months 24 days

Equity-Based Compensation - S_2

Equity-Based Compensation - Schedule of Equity-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total equity-based compensation	$ 483	$ 16	$ 492	$ 48
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total equity-based compensation	163	5	166	16
General and Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total equity-based compensation	$ 320	$ 11	$ 326	$ 32

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Provision or benefit for income taxes	$ 0	$ 0

Net Loss Per Share - Basic and

Net Loss Per Share - Basic and Diluted Net Loss Per Ordinary Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Earnings Per Share [Abstract]
Net loss	$ (4,462)	$ (3,488)		$ (46,570)	$ (9,488)	$ (12,000)
Cumulative dividends on class B and C preference shares	(2,073)	(661)		(6,006)	(1,683)
Net loss attributable to class A ordinary shareholders	$ (6,535)	$ (4,149)		$ (52,576)	$ (11,171)
Net loss per class A ordinary share, basic and diluted	$ (36.88)	$ (23.41)	$ (23.41)	$ (296.70)	$ (63.04)
Weighted-average number of shares used in computing net loss per class A ordinary share, basic and diluted	177,200	177,200		177,200	177,200

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Convertible Preference Shares
Earnings Per Share Basic [Line Items]
Outstanding potentially dilutive securities	1,122,671	584,583	1,122,671	584,583
Stock Warrants
Earnings Per Share Basic [Line Items]
Outstanding potentially dilutive securities	785,248	89,935	785,248	89,935

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - Subsequent Events $ / shares in Units, $ in Millions	Nov. 04, 2021shares	Nov. 01, 2021	Nov. 30, 2021USD ($)$ / sharesshares	Nov. 09, 2021shares	Oct. 31, 2021$ / sharesshares
Subsequent Event [Line Items]
Stock split, description		3.544-for-1 stock split
Stock split, conversion ratio		3.544
Net proceeds from IPO, after deducting underwriting discounts, commissions and offering costs | $			$ 103.3
Convertible preference share issued upon conversion				20,592,413
Common stock shares outstanding				28,815,267
Common stock shares authorized				300,000,000
Warrants exercise price | $ / shares					$ 12.64
Common Stock
Subsequent Event [Line Items]
Warrants granted to purchase ordinary shares					1,611,174
Undesignated Preferred Stock
Subsequent Event [Line Items]
Preferred stock shares authorized				5,000,000
IPO
Subsequent Event [Line Items]
Shares issued			8,222,500
Common stock shares sold, price per share | $ / shares			$ 14
Underwriters
Subsequent Event [Line Items]
Shares issued			1,072,500
2021 Equity Incentive Plan
Subsequent Event [Line Items]
Common stock reserved for issuance	2,465,150
2021 Equity Incentive Plan | Maximum
Subsequent Event [Line Items]
Annual increase in common stock reserved for issuance as percentage of common stock outstanding	4.00%
2021 Employee Stock Purchase Plan
Subsequent Event [Line Items]
Common stock reserved for issuance	257,272
Annual increase in common stock reserved for issuance as percentage of common stock outstanding	1.00%