0001847903-26-000049 | 10-Q | XBRL Viewer | Centessa Pharmaceuticals PLC

Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2026

Summary of Significant Accounting Policies

The accompanying unaudited interim consolidated financial statements should be read in conjunction with the annual audited consolidated financial statements of Centessa Pharmaceuticals plc and related notes which can be found in our Annual Report on Form 10-K for the year ended December 31, 2025 (the “2025 Annual Report”). The Summary of Significant Accounting Policies included in the Company’s annual financial statements have not materially changed, except as set forth below.

Basis of Presentation and Consolidation

The accompanying unaudited interim consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASUs”) promulgated by the Financial Accounting Standards Board (“FASB”).

In the opinion of management, the accompanying unaudited interim consolidated financial statements include all normal and recurring adjustments (which consist primarily of accruals, estimates and assumptions that impact the financial statements) considered necessary to present fairly:

•the Company’s financial position as of March 31, 2026 and as of December 31, 2025;

•the Company’s results of operations for the three months ended March 31, 2026 and March 31, 2025; and

•the Company’s cash flows for the three months ended March 31, 2026 and March 31, 2025.

Operating results for the Company for the three months ended March 31, 2026 are not necessarily indicative of the results that may be expected for the full year. The unaudited interim consolidated financial statements presented herein do not contain all of the required disclosures under U.S. GAAP for annual financial statements. Notes to the financial statements which would substantially duplicate the disclosure contained in the audited financial statements for fiscal 2025 as reported in the 2025 Annual Report have been omitted. Therefore, these unaudited interim consolidated financial statements should be read in conjunction with the annual audited consolidated financial statements and related notes for Centessa Pharmaceuticals plc found in the Form 10-K for the year ended December 31, 2025 filed with the SEC.

The Company’s unaudited interim consolidated financial statements include the accounts of Centessa Pharmaceuticals plc, and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.

Cash, Cash Equivalents, and Restricted Cash

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Company’s consolidated balance sheets that sum to the total of the amounts shown in the consolidated statement of cash flows as of March 31, 2026 and March 31, 2025 (in thousands):


	March 31,
	2026		2025
Cash and cash equivalents	$	62,431	$	105,156
Restricted cash (included within Other non-current assets)	654		654
Total	$	63,085	$	105,810

Investments in Marketable Securities

The Company invests its excess cash in money market funds, U.S. Treasury securities, U.S. government agency securities, corporate debt securities, commercial paper, and municipal bonds. The Company’s investment policy limits investments to money market funds, certain types of debt securities issued by the U.S. Government and its agencies, corporate notes, commercial paper and municipal bonds, and places restrictions on the credit ratings, maturities and concentration by type and issuer. Securities with original maturities of three months or less when purchased are included in cash and cash equivalents. We consider investments with original maturities greater than three months and remaining maturities less than one year to be short-term investments, while remaining maturities greater than one year are classified as long-term investments.

As of March 31, 2026, investments in U.S. government Treasury and agency securities, corporate notes, commercial paper, and municipal bonds were classified as available-for-sale securities, which are recorded at fair value. Unrealized gains and losses on available-for-sale securities are reported net of related income taxes in accumulated other comprehensive income until realized. Purchase premiums and discounts are amortized to interest income over the terms of the related securities.

Reclassifications

Certain amounts in the prior period financial statements have been reclassified to conform to the presentation of the current period financial statements. These reclassifications had no effect on previously reported net loss or comprehensive loss.

Use of Estimates

The preparation of unaudited interim consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the unaudited interim consolidated financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates.

Estimates and assumptions are periodically reviewed and the effects of revisions are reflected in the unaudited interim consolidated financial statements in the period they are determined to be necessary. On an ongoing basis, an evaluation of estimates and judgments are required, including those related to accrued and prepaid research and development expenses, share-based compensation expense and tax related matters. Estimates are based on historical experience, known trends and events, and various other factors that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Changes in

estimates are recorded in the period in which they become known. Actual results may differ from these estimates under different assumptions or conditions.

License and other revenue

The Company recognizes revenues from collaboration, license or other research or sale arrangements when or as performance obligations are satisfied. For milestone payments, the Company assesses, at contract inception, whether the milestones are considered probable of being achieved. If it is probable that a significant revenue reversal will occur, the Company will not record revenue until the uncertainty has been resolved. Milestone payments that are contingent upon regulatory approval are not considered probable until the approvals are obtained as it is outside of the control of the Company. If it is probable that significant revenue reversal will not occur, the Company will estimate the milestone payments using the most likely amount method. The Company reassesses the milestones each reporting period to determine the probability of achievement. Any potential consideration received in the form of royalty or sales-based milestones will be recorded when the customer’s subsequent sales or usages occur.

Net Loss Per Ordinary Share

The following potentially dilutive securities have been excluded from the computation of diluted weighted-average ordinary shares outstanding for the three months ended March 31, 2026 and March 31, 2025, as they would be anti-dilutive:


	Three Months Ended March 31, 2026	Three Months Ended March 31, 2025
Restricted stock awards	—	34,746
Restricted stock units	1,154,321	1,125,346
Stock options	15,428,753	20,300,306
	16,583,074	21,460,398

Organization and Description of Business	3 Months Ended
Organization and Description of Business	Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business Centessa Pharmaceuticals plc (“Centessa” or “the Company”) is a clinical-stage biotechnology company pioneering a new class of therapeutics in orexin-based neuroscience. We are developing a franchise of small molecule orexin receptor 2 (OX2R) agonists designed to address neuroscience diseases underpinned by dysregulation of wakefulness, attention, cognition, mood, and other symptoms, each grounded in the shared biology of the orexin pathway. Centessa was incorporated on October 26, 2020 as a limited liability company under the laws of England and Wales. In connection with the Company’s initial public offering, or IPO, the Company re-registered Centessa Pharmaceuticals Limited as an English public limited company and renamed it as Centessa Pharmaceuticals plc. The Proposed Lilly Transaction On March 31, 2026, we entered into a Transaction Agreement (the “Transaction Agreement”) with Eli Lilly and Company, an Indiana corporation (“Lilly” or “Parent”), and LDH XV Corporation, a Delaware corporation, and direct wholly owned subsidiary of Parent (“Purchaser”), pursuant to which Purchaser (and/or at Parent’s election its nominee(s)), will acquire our entire issued and to be issued share capital (including shares represented by our ADSs) pursuant to a court-sanctioned scheme of arrangement under Part 26 of the UK Companies Act 2006 (the “Scheme of Arrangement” and such acquisition, the “Transaction”), for $38.00 in cash per share, without interest, plus one non-transferable contingent value right entitling the holders to receive up to three contingent cash payments of up to an aggregate of $9.00 per share, contingent upon the achievement of specified milestones set forth in the Contingent Value Rights Agreement (the “CVR Agreement”), substantially in the form attached as Annex I to the Transaction Agreement (such contingent value rights, the “CVRs” and, together with the Cash Consideration, the “Transaction Consideration”). The Transaction is expected to close in the third quarter of 2026, subject to certain customary closing conditions, including the approval of the Scheme of Arrangement by our shareholders, the sanction of the Scheme of Arrangement by the High Court of Justice of England and Wales and receipt of the required regulatory approvals. See “Note 3 – Eli Lilly Agreement” in this Form 10-Q for additional information regarding the Transaction. Risks and Liquidity The Company is subject to risks common to other life science companies in various stages of development including, but not limited to, uncertainty of product development and commercialization, lack of marketing and sales history, development by its competitors of new technological innovations, dependence on key personnel, market acceptance of products, product liability, protection of proprietary technology, ability to raise additional financing and compliance with government regulations in the markets in which the Company is seeking approvals, including U.S. Food and Drug Administration (“FDA”) regulations. If the Company does not successfully advance its programs, into and through human clinical trials and/or enter into collaborations for its programs and commercialize any of its product candidates, it may be unable to produce product revenue or achieve profitability. The Company has incurred losses and negative cash flows from operations since inception and the Company had an accumulated deficit of $1.27 billion as of March 31, 2026. The Company anticipates incurring additional losses until such time, if ever, that it can generate significant sales of the product candidates currently in development. Substantial additional capital will be needed by the Company to fund its operations and to develop its product candidates. The Company entered into a sales agreement, dated January 27, 2023 and amended and restated on November 24, 2025 (the “Sales Agreement”), by and between Centessa Pharmaceuticals plc and Leerink Partners LLC. As sales agent, Leerink Partners LLC provided for the issuance and sale by the Company of up to $250.0 million of its ordinary shares represented by American Depository Shares (“ADSs”) from time to time in “at-the-market” offerings (“ATM Program”). In the three months ended March 31, 2026, the Company has not sold any ordinary shares under the ATM Program. Since the inception of the ATM program in 2023, as of March 31, 2026, the Company sold 4,663,354 ordinary shares under the ATM Program, resulting in net proceeds of approximately $36.6 million under the Sales Agreement. In 2025, the Company completed an offering of its ordinary shares through the sale and issuance of a cumulative 13,372,093 ADSs. Each ADS represents one ordinary share with a nominal value of £0.002 per ordinary share. The completed offerings, which included the underwriters’ over-allotment option to purchase additional shares, was made pursuant to the Shelf registration. The net proceeds of these offerings, after deducting underwriting discounts and commissions and offering expenses, was approximately $269.2 million. The Company intends to use the net proceeds from the offerings, together with its existing cash, cash equivalents, and investments, to fund the continued development of its product candidates, as well as for general corporate purposes. The Company expects its existing cash, cash equivalents and investments as of March 31, 2026 of $533.7 million will be sufficient to fund its expected operating expenses and capital expenditure requirements for at least the next twelve months from the date of issuance of these unaudited interim consolidated financial statements. Emerging Growth Company and Smaller Reporting Company Status The Company is an emerging growth company, as defined in the JOBS Act. Under the JOBS Act, emerging growth companies can delay the adoption of new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. Other exemptions and reduced reporting requirements under the JOBS Act for emerging growth companies include presentation of only two years of audited financial statements in a registration statement for an initial public offering, an exemption from the requirement to provide an auditor’s report on internal controls over financial reporting pursuant to Section 404 of the Sarbanes-Oxley Act of 2002, as amended, an exemption from any requirement that may be adopted by the Public Company Accounting Oversight Board regarding mandatory audit firm rotation and less extensive disclosure about our executive compensation arrangements. The Company has elected to use the extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that (i) it is no longer an emerging growth company or (ii) the Company affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. The Company will remain an emerging growth company until the earliest of (i) the last day of its first fiscal year in which it has total annual gross revenues of $1.235 billion or more, (ii) the last day of its first fiscal year following the fifth anniversary of the closing of its initial public offering, (iii) the date on which it is deemed to be a “large accelerated filer,” under the rules of the SEC, or (iv) the date on which we have issued more than $1.0 billion in non-convertible debt securities during the prior three-year period. As of January 1, 2026, the Company ceased to be a “smaller reporting company” (“SRC”) as defined in the Exchange Act. For the first fiscal quarter of 2026, the Company is no longer permitted to take advantage of scaled disclosure requirements for SRCs. The Company will retain its non-accelerated filer status for its filings due in the fiscal year 2026. The Company anticipates that it will have to comply with the auditor attestation requirements of Section 404(b) of the Sarbanes-Oxley Act for the year ended December 31, 2026, and its independent registered public accounting firm will have to evaluate and report on the effectiveness of internal control over financial reporting.

Debt (Tables)

3 Months Ended

Mar. 31, 2026

Debt Disclosure [Abstract]

Schedule of Debt

Debt as of March 31, 2026 and December 31, 2025 (in thousands):


	March 31, 2026		December 31, 2025
Loan and Security Agreement (“LSA”):
Principal amount	$	110,000	$	110,000
End of term charge	5,500		5,500
Unamortized debt issuance costs and unamortized end of term charge	(5,060)		$	(5,405)
Loan and Security Agreement (carried at amortized cost)	$	110,440	$	110,095
The fair value of LSA, classified as Level 2 under ASC Topic 820, Fair Value Measurement	$	114,318	$	108,515

Schedule of Maturities of Long-Term Debt

Future principal payments, including the end of term charge, are as follows (in thousands):


Year ending:	Payments
2026	—
2027	—
2028	115,500
Total principal payments, including End of Term Charge	$	115,500

Fair Value Measurement - Schedule of Debt Securities, Fair Value of U.S. Treasury Securities and Money Market Fund (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	$ 482,564	$ 549,441
Investments above with no unrealized loss, amortized cost	105,039	309,888
Investments above with unrealized loss, amortized cost	377,525	239,553
Gross unrealized gains	179	505
Investments above with no unrealized loss, gross unrealized gains	179	505
Investments above with unrealized loss, gross unrealized gains	0	0
Gross unrealized losses	(884)	(172)
Investments above with no unrealized loss, gross unrealized loss	0	0
Investments above with unrealized loss, gross unrealized losses	(884)	(172)
Debt securities, available-for-sale, fair value	481,859	549,774
Investments above with no unrealized loss, fair value	105,218	310,393
Investments above with unrealized loss, fair value	376,641	239,381
Money Market fund
Debt Securities, Available-for-Sale [Line Items]
Debt securities, available-for-sale, fair value	606	23,970
Money Market fund \| Cash and cash equivalents
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	606	23,970
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Debt securities, available-for-sale, fair value	606	23,970
U.S. Treasury and government agency securities
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	289,337	307,740
Gross unrealized gains	31	101
Gross unrealized losses	(504)	(109)
Debt securities, available-for-sale, fair value	288,864	307,732
U.S. Treasury and government agency securities \| Cash and cash equivalents
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	9,979	9,974
Gross unrealized gains	0	1
Gross unrealized losses	(1)	0
Debt securities, available-for-sale, fair value	9,978	9,975
U.S. Treasury and government agency securities \| Short-term investments
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	117,574	134,625
Gross unrealized gains	30	73
Gross unrealized losses	(50)	(21)
Debt securities, available-for-sale, fair value	117,554	134,677
U.S. Treasury and government agency securities \| Long-term investments
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	161,784	163,141
Gross unrealized gains	1	27
Gross unrealized losses	(453)	(88)
Debt securities, available-for-sale, fair value	161,332	163,080
Corporate debt securities, included in:
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	178,194	183,126
Gross unrealized gains	148	393
Gross unrealized losses	(340)	(63)
Debt securities, available-for-sale, fair value	178,002	183,456
Corporate debt securities, included in: \| Short-term investments
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	86,741	63,847
Gross unrealized gains	65	141
Gross unrealized losses	(36)	0
Debt securities, available-for-sale, fair value	86,770	63,988
Corporate debt securities, included in: \| Long-term investments
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	91,453	119,279
Gross unrealized gains	83	252
Gross unrealized losses	(304)	(63)
Debt securities, available-for-sale, fair value	91,232	119,468
Commercial paper, included in:
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	9,841	34,605
Gross unrealized gains	0	11
Gross unrealized losses	(7)	0
Debt securities, available-for-sale, fair value	9,834	34,616
Commercial paper, included in: \| Short-term investments
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	9,841	34,605
Gross unrealized gains	0	11
Gross unrealized losses	(7)	0
Debt securities, available-for-sale, fair value	9,834	$ 34,616
Municipal bonds, included in:
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	4,586
Gross unrealized gains	0
Gross unrealized losses	(33)
Debt securities, available-for-sale, fair value	4,553
Municipal bonds, included in: \| Long-term investments
Debt Securities, Available-for-Sale [Line Items]
U.S. Treasury securities, amortized cost	4,586
Gross unrealized gains	0
Gross unrealized losses	(33)
Debt securities, available-for-sale, fair value	$ 4,553

Consolidated Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Income Statement [Abstract]
Unrealized gain on available for sale securities, tax	$ 0.2	$ 0.0
Reclassification adjustment for realized net gain on available for sale marketable securities included in net loss, tax benefit	$ 0.1	$ 0.8

Eli Lilly Agreement	3 Months Ended
Eli Lilly Agreement	Mar. 31, 2026
Restructuring and Related Activities [Abstract]
Eli Lilly Agreement	Eli Lilly Agreement Transaction Agreement On March 31, 2026, we entered into a Transaction Agreement with Lilly and Purchaser. Under the terms of the Transaction Agreement, Purchaser (and/or at Parent’s election, its nominee(s)) will acquire the entire issued and to be issued share capital of the Company (the “Acquisition”) by means of the Scheme of Arrangement. Upon the Scheme of Arrangement becoming effective, the Company will become a wholly owned subsidiary of Purchaser. At the effective time of the Scheme of Arrangement (the “Effective Time”), holders of the Company Shares (including Company Shares represented by our ADSs), will be entitled to receive (i) $38.00 in cash per Company Share, without interest (the “Cash Consideration”), plus (ii) one non-transferable contingent value right entitling the holders to receive contingent cash payments of up to an aggregate of $9.00 per Company Share, contingent upon the achievement of specified milestones set forth in the CVR Agreement. The Acquisition and the Scheme of Arrangement have been recommended by the board of directors of the Company (the “Company Board”) and the boards of directors of Parent and Purchaser. Treatment of Company Equity Awards Pursuant to the Transaction Agreement, at the Effective Time: (i) each outstanding option with an exercise price below the cash consideration (each such option, a “Company Cash-Out Option”), whether vested or unvested, will be canceled and converted into the right to receive (A) a cash payment equal to the excess of the cash consideration over the exercise price, multiplied by the number of shares underlying such Company Cash-Out Option (less applicable withholding), and (B) one CVR per underlying Company Cash-Out Option; (ii) each outstanding option with an exercise price equal to or above the cash consideration (each such option, a “Company Underwater Option”) will fully vest prior to the Effective Time and will be exercisable prior to the Effective Time, with any portion remaining unexercised as of the Effective Time canceled for no consideration; and (iii) each outstanding restricted stock unit otherwise (each such restricted stock unit, a “Company RSU”) will fully vest and, at the Effective Time, will be canceled and converted into the right to receive (A) a cash payment equal to the cash consideration multiplied by the number of shares underlying such Company RSU (less applicable withholding) and (B) one CVR per underlying Company RSU. Conditions to Completion of the Acquisition The Acquisition is subject to customary closing conditions, including, among other things: (a) the approval of the Scheme of Arrangement by a majority in number representing not less than three-fourths (75%) in value of the members or class of members (as the case may be) present and voting (either in person or by proxy) at the Scheme Meeting (as defined in the Transaction Agreement) (including any separate class meeting which may be required by the High Court of Justice of England and Wales (the “Court”)) and the passing of the Company Shareholder Resolution (as defined in the Transaction Agreement) by members representing not less than three-fourths (75%) of the total voting rights of eligible members present and voting (either in person or by proxy) at the Company GM (as defined in the Transaction Agreement), (b) the sanctioning of the Scheme of Arrangement by the Court, (c) the expiration or termination of the applicable waiting period (and any extension thereof) under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”), (d) the absence of any order, decree or ruling that remains in effect and enjoins, prevents, prohibits, or makes illegal the consummation of the Contemplated Transactions, (e) that each party’s respective representations and warranties, subject to certain customary materiality standards set forth in the Transaction Agreement, shall be true and correct as of the Effective Time, (f) the performance or compliance in all material respects with the other party’s obligations under the Transaction Agreement, and (g) no Company Material Adverse Effect (as defined in the Transaction Agreement) having occurred that is continuing at the Effective Time. Representations and Warranties; Covenants The Transaction Agreement includes customary representations, warranties and covenants of the Company, Parent and Purchaser. The Company has agreed, among other things, to use commercially reasonable efforts to operate its business in the ordinary course until the earlier of the Effective Time or the date the Transaction Agreement is terminated, and not to engage in specified types of transactions during such period. The Company has also agreed to customary non-solicitation restrictions, including not to initiate, solicit, knowingly encourage or knowingly facilitate discussions with third parties regarding other proposals for alternative business combination transactions involving the Company or change the recommendation of the Company Board to the Company’s shareholders regarding the Scheme of Arrangement, in each case, except as otherwise permitted by the Transaction Agreement, including to enter into an alternative transaction that constitutes a Superior Proposal (as defined in the Transaction Agreement) in compliance with the Company Board’s fiduciary duties under applicable law and subject to payment of a termination fee. Parent, Purchaser and the Company have agreed to use reasonable best efforts to take actions that may be required in order to obtain antitrust approval of the proposed transaction, subject to certain limitations. Termination and Termination Fee The Transaction Agreement also includes customary termination provisions for both the Company and Parent, including, among others, the right of both parties to terminate for failure to consummate the transactions contemplated by the Transaction Agreement and the Scheme of Arrangement (together, the “Contemplated Transactions”) on or before September 30, 2026, which date shall be extended to March 31, 2027 if the closing condition regarding the expiration of the waiting period (and any extension thereof) under the HSR Act remains unsatisfied. If the Transaction Agreement is terminated under certain circumstances specified in the Transaction Agreement, the Company will be required to pay Parent a termination fee of approximately $63 million (including under specified circumstances in connection with the Company’s entry into an agreement with respect to a Superior Proposal or the Company Board’s change of recommendation in favor of the Acquisition). The parties to the Transaction Agreement are also entitled to specifically enforce the terms and provisions of the Transaction Agreement. Voting and Support Agreements On March 31, 2026, in connection with the execution and delivery of the Transaction Agreement, entities affiliated with Medicxi Ventures, Index Ventures and affiliates of General Atlantic (collectively, the “Supporting Shareholders”), solely in their respective capacities as shareholders of the Company, each entered into a voting and support agreement (collectively, the “Voting Agreements”) with Parent and the Company, pursuant to which each Supporting Shareholder agreed, among other things, (i) to vote (or cause to vote) in favor of the Scheme of Arrangement and the Company Shareholder Resolution, (ii) to vote against other proposals to acquire the Company and (iii) to certain other restrictions on its ability to take actions with respect to the Company and its Company Shares. The Voting Agreements have been included to provide information regarding their terms. They are not intended to modify or supplement any factual disclosures about the applicable Supporting Shareholder or the Company in any public reports filed with the SEC by the Company. The foregoing description of the Voting Agreements is qualified in all respects by reference to the full copy of the form of Voting Agreement. Contingent Value Rights Agreement At or prior to the Effective Time, Parent, Purchaser and Computershare Inc., a Delaware Corporation, and its affiliate, Computershare Trust Company, N.A., a federally chartered trust company, will enter into the CVR Agreement. Pursuant to the Transaction Agreement, each holder of Company Shares (including Company Shares represented by the ADS) and each holder of Company Covered Award (as defined in the CVR Agreement) will be entitled to receive one CVR for each Company Share or Company Covered Award, as applicable, which represents the right to receive contingent cash payments of up to an aggregate of $9.00 per Company Share, without interest and less any applicable tax withholding upon the achievement of specified regulatory milestones for cleminorexton (formerly ORX750) or ORX142 (the “Milestones”). The Milestones include receipt of U.S. regulatory approval for ORX750 or ORX142 for the treatment of idiopathic hypersomnia, any indication and narcolepsy type 2, respectively, in each case prior to the applicable milestone deadline. The CVR will be subject to the terms and conditions set forth in the CVR Agreement. Each CVR represents a contractual right only. The CVRs will not be transferable, except in the limited circumstances specified in the CVR Agreement, will not be evidenced by certificate or other instrument and will not be registered or listed for trading. The CVRs will not have any voting or dividend rights and will not represent any equity or ownership interest in Purchaser or the Company. Any potential payout of the CVR is subject to various risks and uncertainties related to the development of cleminorexton or ORX142 and U.S. Food and Drug Administration clearances. There can be no assurance that the Milestones will be achieved prior to their expiration or termination of the CVR Agreement, or that payment will be required of Parent with respect to the Milestones. The foregoing description of the CVR Agreement does not purport to be complete and is subject to, and is qualified in its entirety by, the full text of the form of the CVR Agreement. The Company has incurred approximately $2.5 million in advisory fees related to the proposed Lilly transaction for the three months ended March 31, 2026.

Share-based Compensation - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2026	Dec. 31, 2025
Number of Shares
Beginning balance (in shares)	19,683,162
Granted (in shares)	2,301,600
Exercised (in shares)	(5,296,060)
Forfeited (in shares)	(1,259,949)
Ending balance (in shares)	15,428,753	19,683,162
Exercisable at end of period (in shares)	7,579,852
Vested and expected to vest at end of period (in shares)	15,428,753
Weighted-Average Exercise Price Per Share
Beginning balance (in USD per share)	$ 10.11
Granted (in USD per share)	25.24
Exercised (in USD per share)	6.44
Forfeited (in USD per share)	13.64
Ending balance (in USD per share)	13.34	$ 10.11
Exercisable at end of period (in USD per share)	9.36
Vested and expected to vest at end of period (in USD per share)	$ 13.34
Weighted-Average Remaining Contractual Term
Options outstanding, weighted-average remaining contractual term	7 years 8 months 12 days	7 years 1 month 6 days
Options exercisable, weighted-average remaining contractual term	6 years 4 months 24 days
Options vested and expected to vest at end of period, weighted-average remaining contractual term	7 years 8 months 12 days
Aggregate Intrinsic Value (in millions)
Aggregate intrinsic value of options	$ 407.0
Aggregate intrinsic value of exercisable	230.1
Aggregate intrinsic value of vested and expected to vest	$ 407.0

Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Debt Instrument [Line Items]
End of term charge	$ 5,500	$ 5,500
Unamortized debt issuance costs and unamortized end of term charge	(5,060)	(5,405)
Loan and Security Agreement (carried at amortized cost)	110,440	110,095
Significant other observable inputs (Level 2)
Debt Instrument [Line Items]
The fair value of LSA, classified as Level 2 under ASC Topic 820, Fair Value Measurement	114,318	108,515
Secured Debt \| Line of Credit
Debt Instrument [Line Items]
Principal amount	$ 110,000	$ 110,000

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-8A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
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Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2026
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying unaudited interim consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASUs”) promulgated by the Financial Accounting Standards Board (“FASB”). In the opinion of management, the accompanying unaudited interim consolidated financial statements include all normal and recurring adjustments (which consist primarily of accruals, estimates and assumptions that impact the financial statements) considered necessary to present fairly: •the Company’s financial position as of March 31, 2026 and as of December 31, 2025; •the Company’s results of operations for the three months ended March 31, 2026 and March 31, 2025; and •the Company’s cash flows for the three months ended March 31, 2026 and March 31, 2025. Operating results for the Company for the three months ended March 31, 2026 are not necessarily indicative of the results that may be expected for the full year. The unaudited interim consolidated financial statements presented herein do not contain all of the required disclosures under U.S. GAAP for annual financial statements. Notes to the financial statements which would substantially duplicate the disclosure contained in the audited financial statements for fiscal 2025 as reported in the 2025 Annual Report have been omitted. Therefore, these unaudited interim consolidated financial statements should be read in conjunction with the annual audited consolidated financial statements and related notes for Centessa Pharmaceuticals plc found in the Form 10-K for the year ended December 31, 2025 filed with the SEC. The Company’s unaudited interim consolidated financial statements include the accounts of Centessa Pharmaceuticals plc, and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Investments in Marketable Securities	Investments in Marketable Securities The Company invests its excess cash in money market funds, U.S. Treasury securities, U.S. government agency securities, corporate debt securities, commercial paper, and municipal bonds. The Company’s investment policy limits investments to money market funds, certain types of debt securities issued by the U.S. Government and its agencies, corporate notes, commercial paper and municipal bonds, and places restrictions on the credit ratings, maturities and concentration by type and issuer. Securities with original maturities of three months or less when purchased are included in cash and cash equivalents. We consider investments with original maturities greater than three months and remaining maturities less than one year to be short-term investments, while remaining maturities greater than one year are classified as long-term investments. As of March 31, 2026, investments in U.S. government Treasury and agency securities, corporate notes, commercial paper, and municipal bonds were classified as available-for-sale securities, which are recorded at fair value. Unrealized gains and losses on available-for-sale securities are reported net of related income taxes in accumulated other comprehensive income until realized. Purchase premiums and discounts are amortized to interest income over the terms of the related securities.
Reclassifications	Reclassifications Certain amounts in the prior period financial statements have been reclassified to conform to the presentation of the current period financial statements. These reclassifications had no effect on previously reported net loss or comprehensive loss.
Use of Estimates	Use of Estimates The preparation of unaudited interim consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the unaudited interim consolidated financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Estimates and assumptions are periodically reviewed and the effects of revisions are reflected in the unaudited interim consolidated financial statements in the period they are determined to be necessary. On an ongoing basis, an evaluation of estimates and judgments are required, including those related to accrued and prepaid research and development expenses, share-based compensation expense and tax related matters. Estimates are based on historical experience, known trends and events, and various other factors that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Changes in estimates are recorded in the period in which they become known. Actual results may differ from these estimates under different assumptions or conditions.
License and other revenue	License and other revenue The Company recognizes revenues from collaboration, license or other research or sale arrangements when or as performance obligations are satisfied. For milestone payments, the Company assesses, at contract inception, whether the milestones are considered probable of being achieved. If it is probable that a significant revenue reversal will occur, the Company will not record revenue until the uncertainty has been resolved. Milestone payments that are contingent upon regulatory approval are not considered probable until the approvals are obtained as it is outside of the control of the Company. If it is probable that significant revenue reversal will not occur, the Company will estimate the milestone payments using the most likely amount method. The Company reassesses the milestones each reporting period to determine the probability of achievement. Any potential consideration received in the form of royalty or sales-based milestones will be recorded when the customer’s subsequent sales or usages occur.

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-SubTopic 10
-Topic 275
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482861/275-10-50-1

+ Details

Summary of Significant Accounting Policies - Schedule of Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025	Dec. 31, 2024
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 62,431	$ 61,299	$ 105,156
Restricted cash (included within Other non-current assets)	654		654
Total	$ 63,085	$ 61,953	105,156	$ 383,221
Maximum
Cash and Cash Equivalents [Line Items]
Total			$ 105,810

Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 1,906	$ 1,906
Less: Accumulated depreciation	(1,184)	(1,099)
Property and equipment, net	722	807
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	1,139	1,139
Office furniture
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	724	724
Office equipment
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 43	$ 43

Share-based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense recognized	$ 10,565	$ 7,883
Weighted-average grant date fair value of options granted (in USD per share)	$ 16.46
Unrecognized compensation expense related to unvested stock option awards	$ 84,000
Share price (in USD per share)	$ 39.72
Aggregate intrinsic value of options	$ 407,000
Aggregate intrinsic value of vested and expected to vest	$ 407,000
Shares repurchased (in shares)	0
Stock issued during period (in shares)	0
Remaining shares reserved for issuance (in shares)	2,708,615
Options and RSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense recognized	$ 2,700
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected weighted average recognition period	3 years 3 months 18 days
2021 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant (in shares)	17,152,838

Fair Value Measurement

3 Months Ended

Mar. 31, 2026

Fair Value Disclosures [Abstract]

Fair Value Measurement

Fair value is the price that could be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Fair value determination in accordance with applicable accounting guidance requires that a number of significant judgments be made. Additionally, fair value is used on a nonrecurring basis to evaluate assets for impairment or as required for disclosure purposes by applicable accounting guidance on disclosures about fair value of financial instruments. Depending on the nature of the assets and liabilities, various valuation techniques and assumptions are used when estimating fair value. The carrying amounts of certain of the Company’s financial instruments, including cash, prepaid expenses, tax incentive receivable and accounts payable, are shown at cost, which approximates fair value due to the short-term nature of these instruments.

The Company follows the provisions of FASB ASC Topic 820, Fair Value Measurement, for financial assets and liabilities measured on a recurring basis. The guidance requires fair value measurements be classified and disclosed in one of the following three categories:

Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.

Level 2: Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liabilities.

Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).

The following fair value hierarchy table presents information about the Company’s financial assets measured and carried at fair value (amounts in thousands):


	Fair value measurement at reporting date using
	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
March 31, 2026
Assets
Money Market fund	$	606	$	—	$	—	$	606
U.S. Treasury and government agency securities	$	49,942	238,922		—		288,864
Corporate debt securities	—		178,002		—		178,002
Commercial Paper	—		9,834		—		9,834
Municipal bonds	—		4,553		—		4,553
Total	$	50,548	$	431,311	$	—	$	481,859


	Fair value measurement at reporting date using
	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
December 31, 2025
Assets
Money Market fund	$	23,970	$	—	$	—	$	23,970
U.S. Treasury and government agency securities	59,842		247,890		—		307,732
Corporate debt securities	—		183,456		—		183,456
Commercial Paper	—		34,616		—		34,616
Total	$	83,812	$	465,962	$	—	$	549,774

We classify our investments in available-for-sale U.S. Treasury securities and the money market fund into Level 1 of the ASC Topic 820 hierarchy because fair values represent quoted market prices for identical or comparable instruments. The Company estimates the fair value of its U.S. government agency securities, corporate debt securities, commercial paper, and municipal bonds by taking into consideration valuations obtained from third-party pricing services. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, issuer credit spreads; benchmark securities; prepayment/default projections based on historical data; and other observable inputs.

The following represents the amortized cost bases and fair values of the Company’s fixed income investments as of March 31, 2026 (amounts in thousands):


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Money Market fund, included in Cash and cash equivalents	$	606	$	—	$	—	$	606

U.S. Treasury and government agency securities, included in:
Cash and cash equivalents	$	9,979	$	—	$	(1)	$	9,978
Short-term investments	117,574		30		(50)		117,554
Long-term investments	161,784		1		(453)		161,332
Total U.S. Treasury and government agency securities	$	289,337	$	31	$	(504)	$	288,864

Corporate debt securities, included in:
Short-term investments	$	86,741	$	65	$	(36)	$	86,770
Long-term investments	91,453		83		(304)		91,232
Total Corporate debt securities	$	178,194	$	148	$	(340)	$	178,002

Commercial paper, included in:
Short-term investments	$	9,841	$	—	$	(7)	$	9,834
Total Commercial paper	$	9,841	$	—	$	(7)	$	9,834

Municipal bonds, included in:
Long-term investments	$	4,586	$	—	$	(33)	$	4,553
Total Municipal bonds	$	4,586	$	—	$	(33)	$	4,553

In aggregate:
Investments above with no unrealized loss	$	105,039	$	179	$	—	$	105,218
Investments above with unrealized loss	$	377,525	$	—	$	(884)	$	376,641
Total investments	$	482,564	$	179	$	(884)	$	481,859

At the end of March 31, 2026, the Company held approximately 73 debt securities, of which 52 were in an unrealized loss position as of the end of the period, with an aggregate fair value of $376.6 million. The Company has not recorded any allowance for credit losses as of March 31, 2026 as it believes the decline in fair value below amortized cost is not related to credit losses. These investments in an unrealized loss position were in this position for less than 12 months and there has been no change in the credit risk of such securities during the period. Securities are evaluated at the end of each reporting period for evidence of the credit-related impairment.

Gross unrealized gains and losses as of March 31, 2026 were $0.2 million and $0.9 million, respectively, recorded in accumulated other comprehensive (loss) income. On March 31, 2026, the Company entered into a Transaction Agreement and plan of merger with Eli Lilly (the “Transaction Agreement”), pursuant to which the Company will be acquired in a transaction expected to close in the third quarter of 2026, subject to the satisfaction of customary closing conditions including regulatory approvals and approval by the Company’s shareholders. The Transaction has not been determined to be probable as of March 31, 2026 for purposes of ASC 805, Business Combinations. Pursuant to the terms of the Transaction Agreement, the Company is required to liquidate its marketable securities portfolio and convert the proceeds to cash and cash equivalents prior to or upon closing the transaction. The Company’s obligation to convert these securities is contingent upon the closing of the Transaction Agreement. Accordingly, the Company has continued to classify its marketable securities as available-for-sale as of March 31, 2026, as the obligation to liquidate is contingent upon a closing that had not occurred as of the balance sheet date. Upon

completion of the transaction, any unrealized gains or losses currently recognized in the accumulated other comprehensive (loss) income will be reclassified into earnings at the time of sale.

The following represents the amortized cost bases and fair values of the Company’s investments and money market fund as of December 31, 2025 (amounts in thousands):


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Money Market fund, included in Cash and cash equivalents	$	23,970	$	—	$	—	$	23,970

U.S. Treasury and government agency securities, included in:

Cash and cash equivalents	$	9,974	$	1	$	—	$	9,975
Short-term investments	134,625		73		(21)		134,677
Long-term investments	163,141		27		(88)		163,080
Total U.S. Treasury and government agency securities	$	307,740	$	101	$	(109)	$	307,732

Corporate debt securities, included in:
Short-term investments	$	63,847	$	141	$	—	$	63,988
Long-term investments	119,279		252		(63)		119,468
Total Corporate debt securities	$	183,126	$	393	$	(63)	$	183,456

Commercial paper, included in:

Short-term investments	$	34,605	$	11	$	—	$	34,616
Total Commercial paper	$	34,605	$	11	$	—	$	34,616

In aggregate:
Investments above with no unrealized loss	$	309,888	$	505	$	—	$	310,393
Investments above with unrealized loss	239,553		—		(172)		239,381
Total investments	$	549,441	$	505	$	(172)	$	549,774

At the end of December 31, 2025, the Company held approximately 79 securities, of which 37 were in an unrealized loss position as of the end of the period, with an aggregate fair value of $239.4 million. The Company has not recorded any allowance for credit losses as of December 31, 2025 as it believes the decline in fair value below amortized cost is not related to credit losses. These investments in an unrealized loss position were in this position for less than 12 months and there has been no change in the credit risk of such securities during the period. The Company does not intend to sell its investments and it is not more likely than not that the Company will be required to sell the securities before recovery of the amortized cost basis of its debt securities. Securities are evaluated at the end of each reporting period for evidence of the credit-related impairment.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 107
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-107

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 100
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-100

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2E
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (h)
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-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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-Name Accounting Standards Codification
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-Paragraph 6A
-Subparagraph (d)
-Publisher FASB
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
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-Section 50
-Paragraph 2
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 940
-SubTopic 820
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478119/940-820-50-1

+ Details

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Income Statement [Abstract]
License and other revenue	$ 0	$ 15,000
Operating expenses:
Research and development	59,891	33,443
General and administrative	19,882	12,334
Loss from operations	(79,773)	(30,777)
Interest and investment income	5,138	7,890
Interest expense	(2,731)	(2,877)
Other non-operating income (expense), net	(1,025)	1,026
Loss before income taxes	(78,391)	(24,738)
Income tax expense	850	1,397
Net loss	(79,241)	(26,135)
Other comprehensive (loss) income:
Foreign currency translation adjustment	(580)	643
Unrealized (loss) gain on available for sale securities during period, net of tax of $0.2 million in 2026 and $0 in 2025	(483)	6
Reclassification adjustment for realized net (loss) gain on available for sale marketable securities included in net loss, net of tax of $0.1 million in 2026 and $0.8 million in 2025	(243)	(2,787)
Other comprehensive (loss) income	(1,306)	(2,138)
Total comprehensive loss	$ (80,547)	$ (28,273)
Net loss per ordinary share - basic (in USD per share)	$ (0.52)	$ (0.20)
Net loss per ordinary share - diluted (in USD per share)	$ (0.52)	$ (0.20)
Weighted average ordinary shares outstanding - basic (in shares)	153,549,733	133,033,541
Weighted average ordinary shares outstanding - diluted (in shares)	153,549,733	133,033,541

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2026
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments As of March 31, 2026, the Company had non-cancellable commitments for purchase of clinical materials, contract manufacturing, maintenance, and committed funding of up to $35.8 million, of which the Company expects to pay $30.2 million within one year and $5.6 million over one year to five years. The amount and timing of these payments vary depending on the rate of progress of development. Future clinical trial expenses have not been included within the purchase commitments because they are generally cancellable at any time upon less than 90 days’ prior written notice. Licensing and Collaborative Arrangements The Company is party to in-licensing and collaboration arrangements to develop and commercialize intellectual property. Included in research and development expense in the Company’s consolidated statement of operations and comprehensive loss for three months ended March 31, 2026 were aggregate incurred expenses of $4.8 million reflecting development milestone costs. As of March 31, 2026, the Company had $3.0 million in-licensing and collaborative arrangement milestone obligations recorded on its balance sheet in Accounts payable. Incentivization Agreements In January 2021, we established incentivization arrangements (as novated, amended or amended and restated from time to time) pursuant to which certain members of the senior management teams of each historically acquired subsidiary in January 2021 are eligible to earn certain payments based on the attainment of corresponding milestone performance by and/or an “exit event” of such historically acquired subsidiary, as applicable to each executive. As defined in the incentivization agreements, an “exit event” includes the sale or disposition (including via an out-licensing) of all or substantially all of the acquired subsidiary’s commercially valuable assets or, in the case of acquired subsidiaries with more than one asset, sale or disposition of one or more of such assets, or any sale or disposition of the applicable subsidiary’s equity which results in the purchaser of the equity acquiring a controlling interest in the applicable subsidiary. Milestones may include the designation of a product candidate or the attainment of approvals, licenses, permits, certifications registrations or authorizations necessary for the sale of a particular product candidate or related molecules in the United States, France, Germany, Italy, Spain or the United Kingdom. Each milestone payment amount for each historically acquired subsidiary is in the low eight figure range to be divided among the members of the respective historically acquired subsidiary’s senior management team and employees according to the terms of its respective incentivization agreement. Any milestone payment earned will be payable in a lump sum within twenty (20) days after attainment of the milestone. Such milestone payment may be accelerated in the event of a Company change of control and would result in the termination of the applicable incentivization agreement. In addition, if a sale of a controlling interest in a historically acquired subsidiary or sale (or grant of an exclusive license) of its respective product candidate occurs prior to attainment of the milestone or within the three (3) year period following attainment of the milestone, an exit payment equal in the low teens percentage of the sales proceeds less any amounts previously paid as a milestone payment (if any) and any fees, costs and expenses of the sale (excluding any earn out, milestone, royalty payment or other contingent payments but including any escrow, holdback or similar amount) will become due and payable to certain employees and members of the historically acquired subsidiary’s senior management team. To the extent an exit event occurs following the occurrence of an adverse event (which includes the failure to achieve milestones within the specified time period), no exit payment will become due unless sale proceeds are in excess of an amount in the eight-figure range. As of March 31, 2026, incentivization agreements associated with Centessa Bioscience, Inc. (formerly Palladio Bioscience, Inc.), Capella Bioscience Limited, Centessa Pharmaceuticals (Morphogen-IX) Limited (formerly Morphogen-IX Limited), Pearl River Bio, Pega-One SAS, ApcinteX Limited and Z-Factor Limited have ceased to apply following the discontinuation of the related programs. Incentivization agreements in respect of our orexin program and LockBody program continue to subsist. The incentivization agreements contain standard termination provisions providing that the agreements shall terminate upon the occurrence of certain events, or automatically on December 31, 2035. Other events that may trigger termination include: •an “exit event”; •the occurrence of certain asset sales in conjunction with certain milestones; and •the date that is three years following achievement of certain milestones. Pursuant to an Amended and Restated Incentivization Deed relating to Orexia Products, as it relates to the orexin program (originally entered into on January 23, 2021 and amended and restated on April 28, 2025, the “Incentivization Deed”), certain members of the senior management team of Orexia Therapeutics Limited are entitled to receive an aggregated cash payment of approximately $50 million upon the consummation of a qualifying change of control of Centessa, including the Proposed Lilly Transaction. Because this obligation arises only upon closing, no liability has been recognized in the unaudited interim consolidated balance sheet as of March 31, 2026. The Company currently expects the Proposed Lilly Transaction to close in the third quarter of 2026, at which time the obligation would become payable. As of March, 31, 2026, there are no obligations that are probable or reasonably possible related to the LockBody program. Contingencies From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of its business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made, and such expenditures can be reasonably estimated.

Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted-Average Ordinary Shares Outstanding (Details) - shares	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted weighted-average ordinary shares outstanding (in shares)	16,583,074	21,460,398
Restricted stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted weighted-average ordinary shares outstanding (in shares)	0	34,746
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted weighted-average ordinary shares outstanding (in shares)	1,154,321	1,125,346
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted weighted-average ordinary shares outstanding (in shares)	15,428,753	20,300,306

Fair Value Measurement - Narrative (Details) $ in Thousands	3 Months Ended	12 Months Ended
Fair Value Measurement - Narrative (Details) $ in Thousands	Mar. 31, 2026 USD ($) security position	Dec. 31, 2025 USD ($) security position
Fair Value Disclosures [Abstract]
Number of debt securities \| security	73	79
Number of debt securities, loss position \| position	52	37
Investments above with unrealized loss, fair value	$ 376,641	$ 239,381
Allowance for credit loss	0	0
Gross unrealized gains	179	505
Gross unrealized losses	$ 884	$ 172

Balance Sheet Components - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Research and development costs	$ 16,680	$ 17,694
Personnel related expenses	3,088	14,467
Professional fees	4,343	1,422
Interest payable	821	840
Operating lease	743	713
Other	241	217
Accrued expenses and other current liabilities	$ 25,916	$ 35,353

Genmab License Agreement (Details) - Genmab A/S - License $ in Millions	Feb. 14, 2025 USD ($) target license	Mar. 31, 2026 USD ($)
Disaggregation of Revenue [Line Items]
Maximum number of undisclosed targets to research products \| target	3
Maximum number of commercial licenses for worldwide development and commercialization of products \| license	3
Upfront payment	$ 15.0	$ 15.0
Maximum additional potential option exercise fee	15.0
Potential additional development and sales milestone	$ 234.0

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
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-Name Accounting Standards Codification
-Section 50
-Paragraph 5
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-URI https://asc.fasb.org/1943274/2147479806/606-10-50-5

Reference 3: http://www.xbrl.org/2003/role/exampleRef
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-Name Accounting Standards Codification
-Section 55
-Paragraph 91
-Subparagraph (a)
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-URI https://asc.fasb.org/1943274/2147479777/606-10-55-91

Reference 4: http://www.xbrl.org/2003/role/exampleRef
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-Paragraph 91
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Reference 5: http://www.xbrl.org/2003/role/exampleRef
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-URI https://asc.fasb.org/1943274/2147479777/606-10-55-91

Reference 6: http://www.xbrl.org/2003/role/exampleRef
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Reference 7: http://www.xbrl.org/2003/role/exampleRef
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Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Topic 606
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-Paragraph 91
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479777/606-10-55-91

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 91
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479777/606-10-55-91

+ Details

Fair Value Measurement (Tables)

3 Months Ended

Mar. 31, 2026

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis

The following fair value hierarchy table presents information about the Company’s financial assets measured and carried at fair value (amounts in thousands):


	Fair value measurement at reporting date using
	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
March 31, 2026
Assets
Money Market fund	$	606	$	—	$	—	$	606
U.S. Treasury and government agency securities	$	49,942	238,922		—		288,864
Corporate debt securities	—		178,002		—		178,002
Commercial Paper	—		9,834		—		9,834
Municipal bonds	—		4,553		—		4,553
Total	$	50,548	$	431,311	$	—	$	481,859


	Fair value measurement at reporting date using
	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
December 31, 2025
Assets
Money Market fund	$	23,970	$	—	$	—	$	23,970
U.S. Treasury and government agency securities	59,842		247,890		—		307,732
Corporate debt securities	—		183,456		—		183,456
Commercial Paper	—		34,616		—		34,616
Total	$	83,812	$	465,962	$	—	$	549,774

Schedule of Debt Securities, Fair Value of U.S. Treasury Securities and Money Market Fund

The following represents the amortized cost bases and fair values of the Company’s fixed income investments as of March 31, 2026 (amounts in thousands):


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Money Market fund, included in Cash and cash equivalents	$	606	$	—	$	—	$	606

U.S. Treasury and government agency securities, included in:
Cash and cash equivalents	$	9,979	$	—	$	(1)	$	9,978
Short-term investments	117,574		30		(50)		117,554
Long-term investments	161,784		1		(453)		161,332
Total U.S. Treasury and government agency securities	$	289,337	$	31	$	(504)	$	288,864

Corporate debt securities, included in:
Short-term investments	$	86,741	$	65	$	(36)	$	86,770
Long-term investments	91,453		83		(304)		91,232
Total Corporate debt securities	$	178,194	$	148	$	(340)	$	178,002

Commercial paper, included in:
Short-term investments	$	9,841	$	—	$	(7)	$	9,834
Total Commercial paper	$	9,841	$	—	$	(7)	$	9,834

Municipal bonds, included in:
Long-term investments	$	4,586	$	—	$	(33)	$	4,553
Total Municipal bonds	$	4,586	$	—	$	(33)	$	4,553

In aggregate:
Investments above with no unrealized loss	$	105,039	$	179	$	—	$	105,218
Investments above with unrealized loss	$	377,525	$	—	$	(884)	$	376,641
Total investments	$	482,564	$	179	$	(884)	$	481,859

The following represents the amortized cost bases and fair values of the Company’s investments and money market fund as of December 31, 2025 (amounts in thousands):


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Money Market fund, included in Cash and cash equivalents	$	23,970	$	—	$	—	$	23,970

U.S. Treasury and government agency securities, included in:

Cash and cash equivalents	$	9,974	$	1	$	—	$	9,975
Short-term investments	134,625		73		(21)		134,677
Long-term investments	163,141		27		(88)		163,080
Total U.S. Treasury and government agency securities	$	307,740	$	101	$	(109)	$	307,732

Corporate debt securities, included in:
Short-term investments	$	63,847	$	141	$	—	$	63,988
Long-term investments	119,279		252		(63)		119,468
Total Corporate debt securities	$	183,126	$	393	$	(63)	$	183,456

Commercial paper, included in:

Short-term investments	$	34,605	$	11	$	—	$	34,616
Total Commercial paper	$	34,605	$	11	$	—	$	34,616

In aggregate:
Investments above with no unrealized loss	$	309,888	$	505	$	—	$	310,393
Investments above with unrealized loss	239,553		—		(172)		239,381
Total investments	$	549,441	$	505	$	(172)	$	549,774

- Definition

Tabular disclosure of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-9

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
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-Name Accounting Standards Codification
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-Paragraph 2
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aaa)
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-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

Reference 11: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

Reference 12: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

+ Details

Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Ordinary Shares	Additional paid-in capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2024		132,631,587
Beginning balance at Dec. 31, 2024	$ 401,545	$ 359	$ 1,385,675	$ 4,213	$ (988,702)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of ordinary shares under ATM program, net of issuance costs (in shares)		372,538
Issuance of ordinary shares under ATM program, net of issuance costs	6,109	$ 1	6,108
Stock option exercises (in shares)		280,716
Stock option exercises	1,880	$ 1	1,879
Share-based compensation expense	7,883		7,883
Vesting of ordinary shares (in shares)		440,909
Vesting of ordinary shares	0	$ 1	(1)
Shares withheld to pay employee withholding tax on share-based compensation (in shares)		(171,152)
Shares withheld to pay employee withholding tax on share-based compensation	(2,897)		(2,897)
Foreign currency translation adjustments	643			643
Unrealized gain (loss) on available for sale securities, net of tax	6			6
Reclassification adjustment for realized net (loss) gain on available for sale marketable securities included in net loss, net of tax	(2,787)			(2,787)
Net loss	(26,135)				(26,135)
Ending balance (in shares) at Mar. 31, 2025		133,554,598
Ending balance at Mar. 31, 2025	$ 386,247	$ 362	1,398,647	2,075	(1,014,837)
Beginning balance (in shares) at Dec. 31, 2025	149,228,068	149,228,068
Beginning balance at Dec. 31, 2025	$ 526,863	$ 405	1,709,978	2,714	(1,186,234)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises (in shares)	5,296,060	5,296,060
Stock option exercises	$ 34,121	$ 13	34,108
Share-based compensation expense	10,565		10,565
Vesting of ordinary shares (in shares)		351,988
Vesting of ordinary shares	0	$ 1	(1)
Shares withheld to pay employee withholding tax on share-based compensation (in shares)		(147,150)
Shares withheld to pay employee withholding tax on share-based compensation	(3,654)		(3,654)
Foreign currency translation adjustments	(580)			(580)
Unrealized gain (loss) on available for sale securities, net of tax	(483)			(483)
Reclassification adjustment for realized net (loss) gain on available for sale marketable securities included in net loss, net of tax	(243)			(243)
Net loss	$ (79,241)				(79,241)
Ending balance (in shares) at Mar. 31, 2026	154,728,966	154,728,966
Ending balance at Mar. 31, 2026	$ 487,348	$ 419	$ 1,750,996	$ 1,408	$ (1,265,475)

Debt - Schedule of Maturities of Long-Term Debt (Details) $ in Thousands	Mar. 31, 2026 USD ($)
Debt Disclosure [Abstract]
2026	$ 0
2027	0
2028	115,500
Total principal payments, including End of Term Charge	$ 115,500

Commitments and Contingencies (Details) $ in Millions	3 Months Ended
Commitments and Contingencies (Details) $ in Millions	Mar. 31, 2026 USD ($)
Lessee, Lease, Description [Line Items]
Purchase obligation	$ 35.8
Purchase obligation, to be paid, within one year	30.2
Purchase obligation, to be paid, year one through five	5.6
Eli Lilly
Lessee, Lease, Description [Line Items]
Estimate of payment	50.0
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Lessee, Lease, Description [Line Items]
Expenses reflecting development milestone payments	4.8
Maximum aggregate development and regulatory milestone payments	$ 3.0

Segment Information (Tables)

3 Months Ended

Mar. 31, 2026

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment

The following table presents reportable segment loss, including significant expenses regularly provided to the CODM, attributable to the Company’s reportable segment for the three months ended March 31, 2026 and March 31, 2025 (in thousands):


	Three Months Ended March 31, 2026		Three Months Ended March 31, 2025
License and other revenue	$	—	$	15,000
Less:
Cleminorexton¹	(20,503)		(13,666)
Other Orexin program expenses1	(23,758)		(6,427)
LockBody technology program expenses	(1,530)		(3,418)
Discontinued R&D program expenses	52		(2,917)
Other R&D expenses:
Personnel expenses2	(11,714)		(6,302)
Research tax incentives	3,630		4,259
Other internal R&D expenses	(1,983)		(815)
General and administrative expenses¹	(13,402)		(8,608)
Share-based compensation	(10,565)		(7,883)
Interest income	5,138		7,890
Interest expense	(2,731)		(2,877)
Other segment items3	(1,025)		1,026
Income tax expense	(850)		(1,397)
Consolidated net loss	$	(79,241)	$	(26,135)

¹ Beginning December 31, 2025, expenses related to the cleminorexton trial have been identified as significant segment expenses. The expenses for this trial have been recast for periods prior to December 31, 2025. These amounts were previously combined and disclosed under “OX2R program expenses” for the quarter ended March 31, 2025.
² Excludes share-based compensation which is presented separately below
3 Other segment items includes Other non-operating income (expense), net

Segment Information

3 Months Ended

Mar. 31, 2026

Segment Reporting [Abstract]

Segment Information

Centessa Pharmaceuticals plc is a clinical-stage biotechnology company pioneering a new class of therapeutics in orexin-based neuroscience. While the Company received non-recurring revenue related to the out-license of Genmab and related antibodies for the three months ended March 31, 2025, the Company’s ability to generate recurring product revenue and to become profitable will depend upon the ability to successfully develop, obtain regulatory approval and commercialize any current and future product candidates.

The Company manages the business as one segment. Its operating results are regularly reviewed by the Company’s Chief Executive Officer, who is the chief operating decision-maker (“CODM”), based on available financial information prepared on a consolidated basis. The CODM evaluates its performance based primarily on research and development efforts and the results of clinical trials. The CODM also utilizes the Company’s long-range plan as a strategic tool to allocate resources according to the Company’s strategic objectives. The consolidated net loss is used to monitor budget versus actual results in assessing segment performance and the allocation of resources. Assets provided to the CODM are consistent with those reported on the Consolidated Balance Sheets with particular emphasis on the Company’s available liquidity, including its cash, cash equivalents and investments.


	Three Months Ended March 31, 2026		Three Months Ended March 31, 2025
License and other revenue	$	—	$	15,000
Less:
Cleminorexton¹	(20,503)		(13,666)
Other Orexin program expenses1	(23,758)		(6,427)
LockBody technology program expenses	(1,530)		(3,418)
Discontinued R&D program expenses	52		(2,917)
Other R&D expenses:
Personnel expenses2	(11,714)		(6,302)
Research tax incentives	3,630		4,259
Other internal R&D expenses	(1,983)		(815)
General and administrative expenses¹	(13,402)		(8,608)
Share-based compensation	(10,565)		(7,883)
Interest income	5,138		7,890
Interest expense	(2,731)		(2,877)
Other segment items3	(1,025)		1,026
Income tax expense	(850)		(1,397)
Consolidated net loss	$	(79,241)	$	(26,135)

¹ Beginning December 31, 2025, expenses related to the cleminorexton trial have been identified as significant segment expenses. The expenses for this trial have been recast for periods prior to December 31, 2025. These amounts were previously combined and disclosed under “OX2R program expenses” for the quarter ended March 31, 2025.
² Excludes share-based compensation which is presented separately below
3 Other segment items includes Other non-operating income (expense), net

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
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-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Balance Sheet Components (Tables)

3 Months Ended

Mar. 31, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consist of the following (amounts in thousands):


	March 31, 2026		December 31, 2025
Research and development costs	$	7,147	$	10,354
Interest receivable	3,279		3,360
Value added tax receivable	1,834		2,131
Insurance related expenses	363		773
Income tax receivable	911		933
Other	2,125		1,827
	$	15,659	$	19,378

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following (amounts in thousands):


	March 31, 2026		December 31, 2025
Research and development costs	$	16,680	$	17,694
Personnel related expenses	3,088		14,467
Professional fees	4,343		1,422
Interest payable	821		840
Operating lease	743		713
Other	241		217
	$	25,916	$	35,353

Schedule of Property and Equipment, Net

Property and equipment, net consisted of the following (amounts in thousands):


	March 31, 2026		December 31, 2025
Computer equipment	$	1,139	$	1,139
Office furniture	724		724
Office equipment	43		43
Property and equipment, at cost	1,906		$	1,906
Less: Accumulated depreciation	(1,184)		(1,099)
Property and equipment, net	$	722	$	807

Share-based Compensation

3 Months Ended

Mar. 31, 2026

Share-Based Payment Arrangement [Abstract]

Share-based Compensation

Centessa Pharmaceuticals plc Stock Option and Incentive Plan

Remaining shares available for future grants as of March 31, 2026 under the 2021 Stock Option and Incentive Plan (the “2021 Plan”) were 17,152,838.

Share-based Compensation Expense

The Company recorded share-based compensation expense in the following expense categories in the unaudited interim consolidated statements of operations and comprehensive loss (amounts in thousands):


	Three Months Ended March 31, 2026		Three Months Ended March 31, 2025
Research and development	$	4,085	$	4,157
General and administrative	6,480		3,726
	$	10,565	$	7,883

The Company recognized $2.7 million of non-cash share-based payment expense due to modifications of certain options and RSUs during the three months ended March 31, 2026, all of which were recorded in general and administrative expense.

Stock Options

The following table summarizes stock option activity for the three months ended March 31, 2026:


	Number of Shares	Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Term	Aggregate Intrinsic Value (in millions)
Balance at January 1, 2026	19,683,162	$	10.11	7.1 years
Granted	2,301,600	$	25.24
Exercised	(5,296,060)	$	6.44
Forfeited	(1,259,949)	$	13.64
Balance at March 31, 2026	15,428,753	$	13.34	7.7 years	$	407.0
Exercisable at March 31, 2026	7,579,852	$	9.36	6.4 years	$	230.1
Vested and expected to vest at March 31, 2026	15,428,753	$	13.34	7.7 years	$	407.0

The weighted-average grant date fair value of options granted was $16.46 per share for the three months ended March 31, 2026. As of March 31, 2026, the total unrecognized compensation expense related to unvested stock option awards was $84.0 million, which the Company expects to recognize over a weighted-average period of 3.3 years.

Based on the trading price of $39.72 per ADS, which is the closing price as of March 31, 2026, the aggregate intrinsic value of outstanding options as of March 31, 2026 was $407.0 million.

During the three months ended March 31, 2026, the fair value of each option was estimated on the date of grant under the Black-Scholes option pricing model using the weighted average assumptions in the table below:


Expected term	6.1 years
Expected stock price volatility	69.1	%
Risk-free interest rate	3.9	%
Expected dividend yield	0	%

Restricted Share Units

The following table summarizes ordinary share activity related to the restricted stock programs for the three months ended March 31, 2026:


	Restricted Stock Units
	Number of Shares		Weighted-Average Grant Date Fair Value Per Share
Unvested at January 1, 2026	984,059		$	7.53
Granted	650,200		$	25.19
Vested	(351,988)		$	6.79
Forfeited	(127,950)		$	6.69
Unvested at March 31, 2026	1,154,321		$	17.79

Unrecognized compensation expense at March 31, 2026 (in thousands)	$	19,403
Expected weighted average recognition period	3.4 years

Employee Share Purchase Plan

As of March 31, 2026, no shares have been purchased or issued under the 2021 Employee Share Purchase Plan (the “ESPP”) and remaining shares reserved for the ESPP were 2,708,615.

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Cash flows from operating activities:
Net loss	$ (79,241)	$ (26,135)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	10,565	7,883
Depreciation and amortization	239	217
Amortization of discount of marketable securities	811	(2,082)
Amortization of debt issuance costs and exit fee of long-term debt	345	312
Change in deferred taxes	828	995
Changes in operating assets and liabilities:
Tax incentive receivable	(3,614)	(4,283)
Prepaid expenses and other assets	3,535	(2,676)
Operating leases, net	53	65
Accounts payable	3,263	(2,095)
Accrued expenses and other liabilities	(9,015)	(29,550)
Other, net	7	103
Net cash used in operating activities	(72,224)	(57,246)
Cash flows from investing activities:
Purchases of investments in marketable securities	(75,539)	(297,476)
Proceeds from maturities of investments in marketable securities	118,246	75,088
Net cash (used in) provided by investing activities	42,707	(222,388)
Cash flows from financing activities:
Proceeds from issuance of shares under ATM program, net of issuance costs	0	6,109
Proceeds from option exercises	34,121	1,763
Payment of employee withholding taxes related to withheld shares for stock based compensation plans	(3,654)	(4,390)
Other, net	0	(396)
Net cash provided by financing activities	30,467	3,086
Effect of exchange rate on cash and cash equivalents	182	(1,517)
Net increase (decrease) in cash, cash equivalents and restricted cash	1,132	(278,065)
Cash, cash equivalents, and restricted cash at beginning of period	61,953	383,221
Cash, cash equivalents, and restricted cash at end of period	63,085	105,156
Supplemental disclosure:
Interest paid	2,404	1,681
Operating lease payments reducing operating lease liabilities	$ 417	$ 408

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2026 shares
Trading Arrangements, by Individual
Non-Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Terminated	false
Tia Bush [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On November 28, 2025, Tia Bush, our Chief Technology and Quality Officer, adopted a trading arrangement for the sale of the Company's ADSs, or a Rule 10b5-1 Trading Plan, that is intended to satisfy the affirmative defense conditions of Securities Exchange Act Rule 10b5-1(c). Ms. Bush’s Rule 10b5-1 Trading Plan, which had a plan end date of December 30, 2026, provided for the sale of up to 160,338 ADSs pursuant to the terms of the plan. On March 31, 2026, Mario Alberto Accardi, our Chief Executive Officer, Tia Bush, our Chief Technology and Quality Officer, Iqbal Hussain, our Chief Legal and Compliance Officer, Karen Anderson, our Chief People Officer, and Gregory Weinhoff, our Chief Business Officer, terminated the trading arrangements they had previously adopted with respect to the sale of our ordinary shares that were intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act.
Name	Tia Bush
Title	Chief Technology and Quality Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	November 28, 2025
Rule 10b5-1 Arrangement Terminated	true
Termination Date	March 31, 2026
Expiration Date	December 30, 2026
Arrangement Duration	397 days
Aggregate Available	160,338
Mario Alberto Accardi [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On January 27, 2026, Mario Alberto Accardi, our Chief Executive Officer, adopted a trading arrangement for the sale of the Company's ADSs, or a Rule 10b5-1 Trading Plan, that is intended to satisfy the affirmative defense conditions of Securities Exchange Act Rule 10b5-1(c). Dr. Accardi’s Rule 10b5-1 Trading Plan, which had a plan end date of April 30, 2027, provided for the sale of up to 110,715 ADSs pursuant to the terms of the plan. On March 31, 2026, Mario Alberto Accardi, our Chief Executive Officer, Tia Bush, our Chief Technology and Quality Officer, Iqbal Hussain, our Chief Legal and Compliance Officer, Karen Anderson, our Chief People Officer, and Gregory Weinhoff, our Chief Business Officer, terminated the trading arrangements they had previously adopted with respect to the sale of our ordinary shares that were intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act.
Name	Mario Alberto Accardi
Title	Chief Executive Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	January 27, 2026
Rule 10b5-1 Arrangement Terminated	true
Termination Date	March 31, 2026
Expiration Date	April 30, 2027
Arrangement Duration	458 days
Aggregate Available	110,715
Iqbal Hussain [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On January 29, 2026, Iqbal Hussain, our Chief Legal and Compliance Officer, adopted a trading arrangement for the sale of the Company's ADSs, or a Rule 10b5-1 Trading Plan, that is intended to satisfy the affirmative defense conditions of Securities Exchange Act Rule 10b5-1(c). Mr. Hussain’s Rule 10b5-1 Trading Plan, which had a plan end date of May 1, 2027, provided for the sale of up to 130,900 ADSs pursuant to the terms of the plan. On March 31, 2026, Mario Alberto Accardi, our Chief Executive Officer, Tia Bush, our Chief Technology and Quality Officer, Iqbal Hussain, our Chief Legal and Compliance Officer, Karen Anderson, our Chief People Officer, and Gregory Weinhoff, our Chief Business Officer, terminated the trading arrangements they had previously adopted with respect to the sale of our ordinary shares that were intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act.
Name	Iqbal Hussain
Title	Chief Legal and Compliance Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	January 29, 2026
Rule 10b5-1 Arrangement Terminated	true
Termination Date	March 31, 2026
Expiration Date	May 1, 2027
Arrangement Duration	457 days
Aggregate Available	130,900
Karen Anderson [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On March 31, 2026, Mario Alberto Accardi, our Chief Executive Officer, Tia Bush, our Chief Technology and Quality Officer, Iqbal Hussain, our Chief Legal and Compliance Officer, Karen Anderson, our Chief People Officer, and Gregory Weinhoff, our Chief Business Officer, terminated the trading arrangements they had previously adopted with respect to the sale of our ordinary shares that were intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act.
Name	Karen Anderson
Title	Chief People Officer
Rule 10b5-1 Arrangement Terminated	true
Termination Date	March 31, 2026
Gregory Weinhoff [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On March 31, 2026, Mario Alberto Accardi, our Chief Executive Officer, Tia Bush, our Chief Technology and Quality Officer, Iqbal Hussain, our Chief Legal and Compliance Officer, Karen Anderson, our Chief People Officer, and Gregory Weinhoff, our Chief Business Officer, terminated the trading arrangements they had previously adopted with respect to the sale of our ordinary shares that were intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act.
Name	Gregory Weinhoff
Title	Chief Business Officer
Rule 10b5-1 Arrangement Terminated	true
Termination Date	March 31, 2026

Share-based Compensation - Schedule of Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Compensation expense recognized	$ 10,565	$ 7,883
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Compensation expense recognized	4,085	4,157
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Compensation expense recognized	$ 6,480	$ 3,726

Debt

3 Months Ended

Mar. 31, 2026

Debt Disclosure [Abstract]

Debt

Debt as of March 31, 2026 and December 31, 2025 (in thousands):


	March 31, 2026		December 31, 2025
Loan and Security Agreement (“LSA”):
Principal amount	$	110,000	$	110,000
End of term charge	5,500		5,500
Unamortized debt issuance costs and unamortized end of term charge	(5,060)		$	(5,405)
Loan and Security Agreement (carried at amortized cost)	$	110,440	$	110,095
The fair value of LSA, classified as Level 2 under ASC Topic 820, Fair Value Measurement	$	114,318	$	108,515

Future principal payments, including the end of term charge, are as follows (in thousands):


Year ending:	Payments
2026	—
2027	—
2028	115,500
Total principal payments, including End of Term Charge	$	115,500

On March 31, 2026, the Company entered into a Transaction Agreement pursuant to which the Company will be acquired in a transaction expected to close in the third quarter of 2026, subject to the satisfaction of customary closing conditions including regulatory approvals and approval by the Company’s shareholders. The Transaction has not been determined to be probable as of March 31, 2026 for purposes of ASC 805, Business Combinations. For additional information regarding the pending transaction, see Note 3. Pursuant to the terms of the Transaction Agreement, the Company is required to prepay in full its outstanding debt under the LSA upon the closing of the transaction. The Company’s obligation to prepay is contingent solely upon the closing of the Transaction, which had not occurred as of March 31, 2026. The Company’s outstanding debt matures in December 2029, and the Company was in compliance with all covenants under the LSA as of March 31, 2026. The Company has therefore continued to classify its outstanding debt under the LSA as noncurrent in the accompanying interim consolidated balance sheet as of March 31, 2026. Upon consummation of the Transaction, the Company expects to repay the outstanding principal balance, together with accrued interest, 2% prepayment fee and end of term charge.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

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+ Details

Eli Lilly Agreement (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2026 USD ($) contingentValue $ / contingentValueRightsAgreement $ / shares
Restructuring and Related Activities [Abstract]
Receivable per company share (in USD per share) \| $ / shares	$ 38.00
Transferable contingent value \| contingentValue	1
Additional cash payment (in USD per share) \| $ / shares	$ 9.00
Termination fee \| $	$ 63.0
Maximum receivable per agreement \| $ / contingentValueRightsAgreement	9
Advisory fees \| $	$ 2.5

Genmab License Agreement	3 Months Ended
Genmab License Agreement	Mar. 31, 2026
Revenue from Contract with Customer [Abstract]
Genmab License Agreement	Genmab License Agreement Background On February 14, 2025, the Company entered into a license agreement (the “License Agreement”) with Genmab A/S (“Genmab”) pursuant to which the Company granted to Genmab an exclusive worldwide license to leverage its proprietary LockBody technology platform to perform research on up to three undisclosed targets selected during a multi-year research period. Additionally, the License Agreement provides Genmab with the option to obtain an exclusive commercial license for worldwide development and commercialization of products against each of the selected three targets. Genmab will conduct all research and development activities under the License Agreement, which may combine the Company’s LockBody technology with Genmab’s proprietary antibody technologies. The LockBody technology platform is designed to improve the therapeutic index of therapies by allowing the conditional activation of potent cell killing mechanisms in diseased tissue, but not in non-diseased tissue. Under the terms of the License Agreement, the Company received a non-refundable upfront payment of $15.0 million related to the license of the LockBody technology platform. Additionally, the Company may receive, in the future, an aggregate of up to $15.0 million when (and if) Genmab exercises the options to acquire the exclusive commercial licenses as discussed above. Further, the Company is eligible to receive potential payouts of up to $234.0 million in development, regulatory and sales milestones per product, as well as tiered royalties ranging in the mid single-digits on annual global net licensed product sales. The License Agreement includes various representations, warranties, covenants, indemnities, and other customary provisions. Unless earlier terminated in accordance with its terms, the License Agreement will expire upon expiration of the last royalty term for the last licensed product. Genmab may terminate the License Agreement or on a target-by-target basis for convenience upon specified time periods. On a target-by-target basis, if Genmab elects not to exercise its option for an exclusive commercial license for worldwide development and commercialization of products against the applicable target (a “Reserved Target”), then the License Agreement will automatically terminate with respect to such Reserved Target. Subject to the terms and specified exceptions set forth in the License Agreement, either party may terminate the License Agreement for the other party’s uncured material breach or insolvency upon a specified notice period. Accounting Treatment The Company assessed the License Agreement in accordance with ASC 606, Revenue with Contracts from Customers, and concluded that the promises in the License Agreement represent a transaction with a customer. The following promises within the License Agreement were identified: (i) the exclusive license of the LockBody technology platform and the ability to perform research on up to three targets, (ii) initial and continuing know-how transfer for the LockBody technology platform, and (iii) participation in a joint steering committee (“JSC”). The promises related to the know-how transfer and JSC participation were determined to be immaterial in the context of the contract as the time commitment and related cost is expected to be inconsequential to the total contract consideration. Accordingly, they were not assessed as performance obligations. Additionally, the Company also evaluated the options to acquire exclusive commercial licenses contained within the License Agreement to determine if they provide Genmab with any material rights. The Company concluded that the options were not issued at a significant and incremental discount and therefore do not provide Genmab with a material right. As such, these options were excluded as performance obligations and will be accounted for when (and if) they are exercised. As a result, the Company determined that the promise to provide the exclusive license constitutes a single performance obligation within the License Agreement. Further, the exclusive license represents functional intellectual property given the Company will not be providing any additional services to Genmab outside of the right to use the licensed intellectual property. Accordingly, the $15.0 million up front payment was recognized as revenue at a point in time, upon delivery of the exclusive license to Genmab at contract inception. As of March 31, 2026, the Company has constrained all variable consideration related to potential milestone payments associated with the License Agreement given the level of uncertainty associated with their achievement. Accordingly, no revenue relating to these milestones has been recognized.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

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-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-13

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org/606/tableOfContent

+ Details

Share-based Compensation (Tables)

3 Months Ended

Mar. 31, 2026

Share-Based Payment Arrangement [Abstract]

Schedule of Share-based Compensation Expense

The Company recorded share-based compensation expense in the following expense categories in the unaudited interim consolidated statements of operations and comprehensive loss (amounts in thousands):


	Three Months Ended March 31, 2026		Three Months Ended March 31, 2025
Research and development	$	4,085	$	4,157
General and administrative	6,480		3,726
	$	10,565	$	7,883

Schedule of Stock Option Activity

The following table summarizes stock option activity for the three months ended March 31, 2026:


	Number of Shares	Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Term	Aggregate Intrinsic Value (in millions)
Balance at January 1, 2026	19,683,162	$	10.11	7.1 years
Granted	2,301,600	$	25.24
Exercised	(5,296,060)	$	6.44
Forfeited	(1,259,949)	$	13.64
Balance at March 31, 2026	15,428,753	$	13.34	7.7 years	$	407.0
Exercisable at March 31, 2026	7,579,852	$	9.36	6.4 years	$	230.1
Vested and expected to vest at March 31, 2026	15,428,753	$	13.34	7.7 years	$	407.0

Schedule of Assumptions Used to Estimate Fair Value of Stock Option Awards


Expected term	6.1 years
Expected stock price volatility	69.1	%
Risk-free interest rate	3.9	%
Expected dividend yield	0	%

Schedule of Restricted Stock and Restricted Stock Unit, Activity

The following table summarizes ordinary share activity related to the restricted stock programs for the three months ended March 31, 2026:


	Restricted Stock Units
	Number of Shares		Weighted-Average Grant Date Fair Value Per Share
Unvested at January 1, 2026	984,059		$	7.53
Granted	650,200		$	25.19
Vested	(351,988)		$	6.79
Forfeited	(127,950)		$	6.69
Unvested at March 31, 2026	1,154,321		$	17.79

Unrecognized compensation expense at March 31, 2026 (in thousands)	$	19,403
Expected weighted average recognition period	3.4 years

Balance Sheet Components

3 Months Ended

Mar. 31, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Balance Sheet Components

Prepaid expenses and other current assets consist of the following (amounts in thousands):


	March 31, 2026		December 31, 2025
Research and development costs	$	7,147	$	10,354
Interest receivable	3,279		3,360
Value added tax receivable	1,834		2,131
Insurance related expenses	363		773
Income tax receivable	911		933
Other	2,125		1,827
	$	15,659	$	19,378

Accrued expenses and other current liabilities consist of the following (amounts in thousands):


	March 31, 2026		December 31, 2025
Research and development costs	$	16,680	$	17,694
Personnel related expenses	3,088		14,467
Professional fees	4,343		1,422
Interest payable	821		840
Operating lease	743		713
Other	241		217
	$	25,916	$	35,353

Property and equipment, net consisted of the following (amounts in thousands):


	March 31, 2026		December 31, 2025
Computer equipment	$	1,139	$	1,139
Office furniture	724		724
Office equipment	43		43
Property and equipment, at cost	1,906		$	1,906
Less: Accumulated depreciation	(1,184)		(1,099)
Property and equipment, net	$	722	$	807

Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2026

Accounting Policies [Abstract]

Schedule of Reconciliation of Cash, Cash Equivalents, and Restricted Cash


	March 31,
	2026		2025
Cash and cash equivalents	$	62,431	$	105,156
Restricted cash (included within Other non-current assets)	654		654
Total	$	63,085	$	105,810

Schedule of Restrictions on Cash and Cash Equivalents


	March 31,
	2026		2025
Cash and cash equivalents	$	62,431	$	105,156
Restricted cash (included within Other non-current assets)	654		654
Total	$	63,085	$	105,810

Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted-Average Ordinary Shares Outstanding


	Three Months Ended March 31, 2026	Three Months Ended March 31, 2025
Restricted stock awards	—	34,746
Restricted stock units	1,154,321	1,125,346
Stock options	15,428,753	20,300,306
	16,583,074	21,460,398

Share-based Compensation - Summary of Restricted Stock and Restricted Stock Unit, Activity (Details) - Restricted Stock Units $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2026 USD ($) $ / shares shares
Number of Shares
Unvested beginning balance (in shares) \| shares	984,059
Granted (in shares) \| shares	650,200
Vested (in shares) \| shares	(351,988)
Forfeited (in shares) \| shares	(127,950)
Unvested ending balance (in shares) \| shares	1,154,321
Unrecognized compensation expense excluding options \| $	$ 19,403
Expected weighted average recognition period	3 years 4 months 24 days
Weighted-Average Grant Date Fair Value Per Share
Unvested beginning balance (in USD per share) \| $ / shares	$ 7.53
Granted (in USD per share) \| $ / shares	25.19
Vested (in USD per share) \| $ / shares	6.79
Forfeited (in USD per share) \| $ / shares	6.69
Unvested ending balance (in USD per share) \| $ / shares	$ 17.79

Fair Value Measurement - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Assets
Debt securities, available-for-sale, fair value	$ 481,859	$ 549,774
Total	481,859	549,774
Money Market fund
Assets
Debt securities, available-for-sale, fair value	606	23,970
U.S. Treasury and government agency securities
Assets
Debt securities, available-for-sale, fair value	288,864	307,732
Corporate debt securities
Assets
Debt securities, available-for-sale, fair value	178,002	183,456
Commercial Paper
Assets
Debt securities, available-for-sale, fair value	9,834	34,616
Municipal bonds
Assets
Debt securities, available-for-sale, fair value	4,553
Quoted prices in active markets for identical assets (Level 1)
Assets
Total	50,548	83,812
Quoted prices in active markets for identical assets (Level 1) \| Money Market fund
Assets
Debt securities, available-for-sale, fair value	606	23,970
Quoted prices in active markets for identical assets (Level 1) \| U.S. Treasury and government agency securities
Assets
Debt securities, available-for-sale, fair value	49,942	59,842
Quoted prices in active markets for identical assets (Level 1) \| Corporate debt securities
Assets
Debt securities, available-for-sale, fair value	0	0
Quoted prices in active markets for identical assets (Level 1) \| Commercial Paper
Assets
Debt securities, available-for-sale, fair value	0	0
Quoted prices in active markets for identical assets (Level 1) \| Municipal bonds
Assets
Debt securities, available-for-sale, fair value	0
Significant other observable inputs (Level 2)
Assets
Total	431,311	465,962
Significant other observable inputs (Level 2) \| Money Market fund
Assets
Debt securities, available-for-sale, fair value	0	0
Significant other observable inputs (Level 2) \| U.S. Treasury and government agency securities
Assets
Debt securities, available-for-sale, fair value	238,922	247,890
Significant other observable inputs (Level 2) \| Corporate debt securities
Assets
Debt securities, available-for-sale, fair value	178,002	183,456
Significant other observable inputs (Level 2) \| Commercial Paper
Assets
Debt securities, available-for-sale, fair value	9,834	34,616
Significant other observable inputs (Level 2) \| Municipal bonds
Assets
Debt securities, available-for-sale, fair value	4,553
Significant unobservable inputs (Level 3)
Assets
Total	0	0
Significant unobservable inputs (Level 3) \| Money Market fund
Assets
Debt securities, available-for-sale, fair value	0	0
Significant unobservable inputs (Level 3) \| U.S. Treasury and government agency securities
Assets
Debt securities, available-for-sale, fair value	0	0
Significant unobservable inputs (Level 3) \| Corporate debt securities
Assets
Debt securities, available-for-sale, fair value	0	0
Significant unobservable inputs (Level 3) \| Commercial Paper
Assets
Debt securities, available-for-sale, fair value	0	$ 0
Significant unobservable inputs (Level 3) \| Municipal bonds
Assets
Debt securities, available-for-sale, fair value	$ 0

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Current assets:
Cash and cash equivalents	$ 62,431	$ 61,299
Short-term investments	214,158	233,281
Tax incentive receivable	56,431	53,917
Prepaid expenses and other current assets	15,659	19,378
Total current assets	348,679	367,875
Long-term investments	257,117	282,548
Property and equipment, net	722	807
Operating lease right-of-use assets	9,794	10,047
Deferred tax asset	24,171	24,778
Other non-current assets	1,280	1,440
Total assets	641,763	687,495
Current liabilities:
Accounts payable	10,658	7,582
Accrued expenses and other current liabilities	25,916	35,353
Total current liabilities	36,574	42,935
Long term debt	110,440	110,095
Operating lease liabilities	7,372	7,573
Other liabilities	29	29
Total liabilities	154,415	160,632
Commitments and contingencies (Note 8)
Shareholders’ equity:
Ordinary shares: £0.002 nominal value: 222,480,776 shares authorized, 154,728,966 issued and outstanding at March 31, 2026: 222,480,776 shares authorized, 149,228,068 issued and outstanding at December 31, 2025	419	405
Additional paid-in capital	1,750,996	1,709,978
Accumulated other comprehensive income	1,408	2,714
Accumulated deficit	(1,265,475)	(1,186,234)
Total shareholders’ equity	487,348	526,863
Total liabilities and shareholders' equity	$ 641,763	$ 687,495

Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Research and development costs	$ 7,147	$ 10,354
Interest receivable	3,279	3,360
Value added tax receivable	1,834	2,131
Insurance related expenses	363	773
Income tax receivable	911	933
Other	2,125	1,827
Prepaid expenses and other current assets	$ 15,659	$ 19,378

Consolidated Balance Sheets (Parenthetical) - £ / shares	Mar. 31, 2026	Dec. 31, 2025
Statement of Financial Position [Abstract]
Ordinary shares, nominal value (in pound sterling per share)	£ 0.002	£ 0.002
Ordinary shares, shares authorized (in shares)	222,480,776	222,480,776
Ordinary shares, shares issued (in shares)	154,728,966	149,228,068
Ordinary shares, shares outstanding (in shares)	154,728,966	149,228,068

Organization and Description of Business (Details) $ / shares in Units, $ in Thousands	12 Months Ended	38 Months Ended
	Dec. 31, 2025 USD ($) shares	Mar. 31, 2026 USD ($) contingentValue $ / shares shares	Mar. 31, 2026 £ / shares	Dec. 31, 2025 £ / shares	Jan. 27, 2023 USD ($)
Subsidiary, Sale of Stock [Line Items]
Receivable per company share (in USD per share) \| $ / shares		$ 38.00
Transferable contingent value \| contingentValue		1
Additional cash payment (in USD per share) \| $ / shares		$ 9.00
Accumulated deficit	$ (1,186,234)	$ (1,265,475)
Ordinary shares, nominal value (in pound sterling per share) \| £ / shares			£ 0.002	£ 0.002
Cash and cash equivalents and short-term investments		$ 533,700
ATM Program
Subsidiary, Sale of Stock [Line Items]
Sale of stock, consideration receivable (up to)					$ 250,000
Shares sold in offering (in shares) \| shares		4,663,354
Aggregate net proceeds from shares sold		$ 36,600
Underwriter Offering
Subsidiary, Sale of Stock [Line Items]
Shares sold in offering (in shares) \| shares	13,372,093
Aggregate net proceeds from shares sold	$ 269,200
Number of shares issued per ordinary share (in shares) \| shares	1
Ordinary shares, nominal value (in pound sterling per share) \| £ / shares				£ 0.002

Cover - shares	3 Months Ended
Cover - shares	Mar. 31, 2026	Apr. 28, 2026
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2026
Entity Transition Report	false
Entity File Number	001-40445
Entity Registrant Name	CENTESSA PHARMACEUTICALS PLC
Entity Incorporation, State or Country Code	X0
Entity Tax Identification Number	98-1612294
Entity Address, Address Line One	3rd Floor
Entity Address, Address Line Two	1 Ashley Road
Entity Address, Address Line Three	Altrincham
Entity Address, City or Town	Cheshire
Entity Address, Postal Zip Code	WA14 2DT
Entity Address, Country	GB
Country Region	1
City Area Code	(617)
Local Phone Number	468-5770
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		154,728,966
Amendment Flag	false
Document Fiscal Year Focus	2026
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001847903
Current Fiscal Year End Date	--12-31
Ordinary shares
Document Information [Line Items]
Title of 12(b) Security	Ordinary shares, nominal value £0.002 per share
Trading Symbol	CNTA
Security Exchange Name	NASDAQ
American Depositary Shares
Document Information [Line Items]
Title of 12(b) Security	American Depositary Shares, each representing one ordinary share, nominal value £0.002 per share
Trading Symbol	CNTA
Security Exchange Name	NASDAQ

Share-based Compensation - Schedule of Assumptions Used to Estimate Fair Value of Stock Option Awards (Details) - Stock options	3 Months Ended
	Mar. 31, 2026
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	6 years 1 month 6 days
Expected stock price volatility	69.10%
Risk-free interest rate	3.90%
Expected dividend yield	0.00%

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)
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-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Segment Information (Details) $ in Thousands	3 Months Ended
Segment Information (Details) $ in Thousands	Mar. 31, 2026 USD ($) segment	Mar. 31, 2025 USD ($)
Segment Reporting [Abstract]
Number of operating segments \| segment	1
Number of reportable segments \| segment	1
Segment Reporting, Asset Reconciling Item [Line Items]
License and other revenue	$ 0	$ 15,000
Other R&D expenses:
General and administrative expenses	(19,882)	(12,334)
Share-based compensation	(10,565)	(7,883)
Interest income	5,138	7,890
Interest expense	(2,731)	(2,877)
Income tax expense	(850)	(1,397)
Consolidated net loss	(79,241)	(26,135)
Reportable Segment
Segment Reporting, Asset Reconciling Item [Line Items]
License and other revenue	0	15,000
Less:
Cleminorexton	(20,503)	(13,666)
Other Orexin program expenses	(23,758)	(6,427)
LockBody technology program expenses	(1,530)	(3,418)
Discontinued R&D program expenses	52	(2,917)
Other R&D expenses:
Personnel expenses	(11,714)	(6,302)
Research tax incentives	3,630	4,259
Other internal R&D expenses	(1,983)	(815)
General and administrative expenses	(13,402)	(8,608)
Share-based compensation	(10,565)	(7,883)
Interest income	5,138	7,890
Interest expense	(2,731)	(2,877)
Other segment items	(1,025)	1,026
Income tax expense	(850)	(1,397)
Consolidated net loss	$ (79,241)	$ (26,135)