Organization and Description of Business	6 Months Ended
Jun. 30, 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 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. 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 $1.07 billion as of June 30, 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. The Company entered into a Sales Agreement, dated January 27, 2023, by and between Centessa Pharmaceuticals plc and Leerink Partners LLC (formerly SVB Securities LLC). As sales agent, Leerink Partners LLC will provide for the issuance and sale by the Company of up to $125.0 million of its ordinary shares represented by American Depository Shares (“ADSs”) from time to time in “at-the-market” offerings (“ATM Program”). In the six months ended June 30, 2025, the Company sold 372,538 ordinary shares under the ATM Program, resulting in net proceeds of $6.1 million, all of which were collected during the first quarter of 2025. Since the inception of the ATM program in 2023, as of June 30, 2025, the Company has sold 4,663,354 ordinary shares under the ATM Program, resulting in net proceeds to us of approximately $36.6 million. The Company expects its existing cash, cash equivalents and investments as of June 30, 2025 of $404.1 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, which means the market value of equity securities that is held by non-affiliates exceeds $700.0 million as of the prior June 30th and (iv) the date on which we have issued more than $1.0 billion in non-convertible debt securities during the prior three-year period. The Company is also a “smaller reporting company” as defined in the Securities Exchange Act of 1934 (the “Exchange Act”). If it is a smaller reporting company at the time we cease to be an emerging growth company, the Company may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company it may choose to present only the two most recent fiscal years of audited financial statements in its Annual Report on Form 10-K and, similar to emerging growth companies, smaller reporting companies have reduced disclosure obligations regarding executive compensation. On the last business day of its second quarter in 2025, the aggregate market value of the Company’s shares of common stock held by non-affiliates exceeded $700 million. As a result, as of December 31, 2025, the Company will be considered a “large accelerated filer” as defined in Rule 12b-2 under the Exchange Act, and will cease to be an “emerging growth company” as defined in the JOBS Act and a “smaller reporting company” as defined in the Exchange Act. The Company will no longer be exempt from the auditor attestation requirements of Section 404(b) of the Sarbanes-Oxley Act, and its independent registered public accounting firm will evaluate and report on the effectiveness of internal control over financial reporting. The Company will also no longer be permitted to take advantage of reduced reporting requirements for smaller reporting companies.

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 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 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 $1.07 billion as of June 30, 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.

The Company entered into a Sales Agreement, dated January 27, 2023, by and between Centessa Pharmaceuticals plc and Leerink Partners LLC (formerly SVB Securities LLC). As sales agent, Leerink Partners LLC will provide for the issuance and sale by the Company of up to $125.0 million of its ordinary shares represented by American Depository Shares (“ADSs”) from time to time in “at-the-market” offerings (“ATM Program”). In the six months ended June 30, 2025, the Company sold 372,538 ordinary shares under the ATM Program, resulting in net proceeds of $6.1 million, all of which were collected during the first quarter of 2025. Since the inception of the ATM program in 2023, as of June 30, 2025, the Company has sold 4,663,354 ordinary shares under the ATM Program, resulting in net proceeds to us of approximately $36.6 million.

The Company expects its existing cash, cash equivalents and investments as of June 30, 2025 of $404.1 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.

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, which means the market value of equity securities that is held by non-affiliates exceeds $700.0 million as

The Company is also a “smaller reporting company” as defined in the Securities Exchange Act of 1934 (the “Exchange Act”). If it is a smaller reporting company at the time we cease to be an emerging growth company, the Company may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company it may choose to present only the two most recent fiscal years of audited financial statements in its Annual Report on Form 10-K and, similar to emerging growth companies, smaller reporting companies have reduced disclosure obligations regarding executive compensation.

On the last business day of its second quarter in 2025, the aggregate market value of the Company’s shares of common stock held by non-affiliates exceeded $700 million. As a result, as of December 31, 2025, the Company will be considered a “large accelerated filer” as defined in Rule 12b-2 under the Exchange Act, and will cease to be an “emerging growth company” as defined in the JOBS Act and a “smaller reporting company” as defined in the Exchange Act. The Company will no longer be exempt from the auditor attestation requirements of Section 404(b) of the Sarbanes-Oxley Act, and its independent registered public accounting firm will evaluate and report on the effectiveness of internal control over financial reporting. The Company will also no longer be permitted to take advantage of reduced reporting requirements for smaller reporting companies.