Organization and Description of Business	12 Months Ended
Dec. 31, 2025
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 pharmaceutical company that aims to discover, develop and ultimately deliver medicines that are transformational for patients. Centessa was incorporated on October 26, 2020 as a limited liability company under the laws of England and Wales. In connection with the IPO in June 2021, the Company re-registered Centessa Pharmaceuticals Limited as an English public limited company and renamed it as Centessa Pharmaceuticals plc. Risks and Liquidity The Company is subject to risks common to other life science companies in early stages of development including, but not limited to, uncertainty of product development and commercialization, lack of marketing and sales history, development of new technological innovations by its competitors, 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 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 $1.2 billion as of December 31, 2025. 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. On December 30, 2024, the Company entered into a loan and security agreement (the “Loan and Security Agreement”) with Oxford Finance LLC (“Oxford”), as collateral agent and a lender, and the other lenders from time to time party thereto (collectively, the “Lenders”), pursuant to which the Lenders have agreed to lend the Company an aggregate principal amount of up to $200.0 million in a series of term loans (the “Term Loans”). Pursuant to the Loan and Security Agreement, the Company received $110.0 million (the “Initial Term Loan”) and incurred $1.1 million of debt issuance costs inclusive of facility and legal fees. The Company has access to up to an additional $40.0 million of loan proceeds in an additional tranche which is available during the period commencing on the date of the occurrence of the Clinical Milestone (as defined in the Loan and Security Agreement) through the earlier of: (i) 90 days following the Clinical Milestone and (ii) June 30, 2028. An additional $50.0 million may be made available to the Company at the Lenders’ sole discretion. The term loans are set to mature on December 1, 2029 and, following an interest-only period, will begin to amortize in equal monthly installments beginning on February 1, 2029. However, if the Extension Event as defined in the Agreement occurs, then at the Company’s option, the term loans could begin to amortize in equal monthly installments beginning on February 1, 2030, and the maturity date will be extended to December 1, 2030. Substantially all of the proceeds from the Initial Term Loan were used to repay in full the approximately $110 million aggregate principal amount outstanding, accrued interest and fees related to the Company’s existing note purchase agreement (the “NPA”) with Three Peaks Capital Solutions Aggregator Fund and Cocoon SA LLC, an affiliate of Oberland Capital Management LLC (collectively, “Oberland Capital”). (See - Note 6 "Debt"). Shelf Registration Statement and Equity offerings On September 11, 2024, the Company filed an automatic shelf registration statement on Form S-3ASR (“Shelf”) registering an unspecified amount of the Company’s ordinary shares, American Depository Shares representing ordinary shares, debt securities, warrants, and/or units or any combination thereof with the U.S. Securities and Exchange Commission (the “SEC”) under the Securities Act of 1933, as amended. The Shelf automatically became effective upon filing. Under the Shelf, Centessa may offer securities from time to time in one or more offerings, at prices and on terms to be determined by market conditions at the time of offering. The specifics of any future offerings, along with the use of proceeds of any securities offered, will be described in detail in a prospectus supplement, or other offering materials, at the time of any offering. 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 year ended December 31, 2025, the Company sold 372,538 ordinary shares under the ATM Program, resulting in net proceeds of $6.1 million. On a life to date basis, as of December 31, 2025, 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 2024, the Company completed offerings of its ordinary shares through the sale and issuance of a cumulative 29,932,626 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 $349.9 million. In 2025, the Company completed offerings 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 December 31, 2025 of $577.1 million will be sufficient to fund its expected operating expenses and capital expenditure requirements for at least the next 12 months from the date of issuance of these consolidated financial statements.

Centessa Pharmaceuticals plc (“Centessa” or “the Company”) is a clinical-stage pharmaceutical company that aims to discover, develop and ultimately deliver medicines that are transformational for patients. Centessa was incorporated on October 26, 2020 as a limited liability company under the laws of England and Wales. In connection with the IPO in June 2021, the Company re-registered Centessa Pharmaceuticals Limited as an English public limited company and renamed it as Centessa Pharmaceuticals plc.

The Company is subject to risks common to other life science companies in early stages of development including, but not limited to, uncertainty of product development and commercialization, lack of marketing and sales history, development of new technological innovations by its competitors, 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 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 $1.2 billion as of December 31, 2025. 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.

On December 30, 2024, the Company entered into a loan and security agreement (the “Loan and Security Agreement”) with Oxford Finance LLC (“Oxford”), as collateral agent and a lender, and the other lenders from time to time party thereto (collectively, the “Lenders”), pursuant to which the Lenders have agreed to lend the Company an aggregate principal amount of up to $200.0 million in a series of term loans (the “Term Loans”).

Pursuant to the Loan and Security Agreement, the Company received $110.0 million (the “Initial Term Loan”) and incurred $1.1 million of debt issuance costs inclusive of facility and legal fees. The Company has access to up to an additional $40.0 million of loan proceeds in an additional tranche which is available during the period commencing on the date of the occurrence of the Clinical Milestone (as defined in the Loan and Security Agreement) through the earlier of: (i) 90 days following the Clinical Milestone and (ii) June 30, 2028. An additional $50.0 million may be made available to the Company at the Lenders’ sole discretion.

The term loans are set to mature on December 1, 2029 and, following an interest-only period, will begin to amortize in equal monthly installments beginning on February 1, 2029. However, if the Extension Event as defined in the Agreement occurs, then at the Company’s option, the term loans could begin to amortize in equal monthly installments beginning on February 1, 2030, and the maturity date will be extended to December 1, 2030.

Substantially all of the proceeds from the Initial Term Loan were used to repay in full the approximately $110 million aggregate principal amount outstanding, accrued interest and fees related to the Company’s existing note purchase agreement (the “NPA”) with Three Peaks Capital Solutions Aggregator Fund and Cocoon SA LLC, an affiliate of Oberland Capital Management LLC (collectively, “Oberland Capital”). (See - Note 6 "Debt").

On September 11, 2024, the Company filed an automatic shelf registration statement on Form S-3ASR (“Shelf”) registering an unspecified amount of the Company’s ordinary shares, American Depository Shares representing ordinary shares, debt securities, warrants, and/or units or any combination thereof with the U.S. Securities and Exchange Commission (the “SEC”) under the Securities Act of 1933, as amended. The Shelf automatically became effective upon filing. Under the Shelf, Centessa may offer securities from time to time in one or more offerings, at prices and on terms to be determined by market conditions at the time of offering. The specifics of any future offerings, along with the use of

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 year ended December 31, 2025, the Company sold 372,538 ordinary shares under the ATM Program, resulting in net proceeds of $6.1 million. On a life to date basis, as of December 31, 2025, 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 2024, the Company completed offerings of its ordinary shares through the sale and issuance of a cumulative 29,932,626 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 $349.9 million.

In 2025, the Company completed offerings 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.