Organization and Description of Business	12 Months Ended
Dec. 31, 2021
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 with a Research & Development (“R&D”) innovation engine that aims to discover, develop and ultimately deliver impactful medicines to 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, we re-registered Centessa Pharmaceuticals Limited as an English public limited company and renamed it as Centessa Pharmaceuticals plc. In January 2021, the management and equity holders of ApcinteX Limited, Capella Biosciences Limited, Inexia Limited, Janpix Limited, LockBody Therapeutics Ltd, Morphogen-IX Limited, Orexia Limited, Palladio Biosciences, Inc., PearlRiver Bio GmbH, Pega-One S.A.S., and Z Factor Limited (together, the “Centessa Subsidiaries”), contributed the Centessa Subsidiaries to Centessa, in a share for share exchange, after which these companies became wholly-owned subsidiaries of Centessa. As the Company had no significant operations prior to the contribution of the Centessa Subsidiaries, and the registrant was required to present two years of historical financial statements in its prospectus filed with the SEC on June 2, 2021, the Company’s management (“Management”) sought to identify a predecessor, for which it could include audited historical financial statements, to satisfy the filing requirement. As such, Management sought to identify the predecessor from the population of portfolio companies, which would represent a sizable portion of the historical results of the entities later contributed to Centessa. Entities affiliated with Medicxi manage multiple investment funds, including – Medicxi Ventures I LP, Medicxi Growth I LP, and Medicxi Secondary I LP. In addition, entities affiliated with Medicxi act as sub advisors to Index Ventures Life VI (Jersey) Limited which advises the managing general partner of Index Ventures Life VI (Jersey), L.P. (all funds collectively are referred to as the “Funds”). Management determined the companies owned by Index Ventures Life VI (Jersey), LP individually represent some of the earliest investments by the Funds. These companies (together, the “Centessa Predecessor Group” or the “Group”) are: •Z Factor Limited (“Z Factor”) •LockBody Therapeutics Ltd (“LockBody”) •Morphogen-IX Limited (“Morphogen-IX”) As the above entities that comprise the Centessa Predecessor Group were historically under the common control of Index Ventures Life VI (Jersey), LP, the historical financial statements of the Group for periods prior to January 30, 2021 are presented on a combined basis and are denoted as “Predecessor” within these financial statements. Subsequent to the contribution of the Centessa Subsidiaries to Centessa, the financial activities of Centessa and all Centessa Subsidiaries are being presented on a consolidated basis and are denoted as “Successor” within these financial statements. Initial Public Offering In June 2021, the Company completed an initial public offering (“IPO”) of its ordinary shares through the sale and issuance of 16,500,000 American Depositary Shares (“ADSs”), at an initial price of $20.00 per ADS. Each ADS represents one ordinary share with a nominal value of £0.002 per ordinary share. Following the close of the IPO, the underwriters fully exercised their option to purchase an additional 2,475,000 ADSs at the initial public offering price of $20.00 per ADS. The Company received aggregate net proceeds of $344.1 million in connection with the IPO and subsequent exercise of the underwriter’s options after deducting underwriting discounts, commissions and other offering expenses paid or to be paid. Risks and Liquidity The Group and the Company are 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 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, including the Centessa Subsidiaries’ 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 Group and the Company have incurred losses and negative cash flows from operations since inception and the Company had an accumulated deficit of $385.7 million as of December 31, 2021. The Company anticipates incurring additional losses until such time, if ever, that it can generate significant sales of the product candidates currently in development by the Centessa Subsidiaries. Substantial additional capital will be needed by the Company to fund its operations (including those of the Centessa Subsidiaries) and to develop its product candidates. In October 2021, the Company entered into a Note Purchase Agreement with Oberland Capital Management LLC (“Oberland Capital”). Under the terms of the agreement, Oberland Capital will purchase up to $300.0 million of 6-year, interest-only (initial interest rate is 8.0% per annum), senior secured notes (the Notes) from the Company including $75.0 million, funded on October 4, 2021, $125.0 million available within 24 months at the Company’s option, and $100.0 million available to fund Mergers and Acquisitions (“M&A”), in-licensing, or other strategic transactions, at the option of the Company and Oberland Capital (See - Note 6 "Debt"). The Company expects its existing cash and cash equivalents as of December 31, 2021 of $595.1 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. Global Pandemic – COVID-19 On March 10, 2020, the WHO characterized the novel COVID-19 virus as a global pandemic. The Company is continuing to proactively monitor the COVID-19 global pandemic, to assess the potential impact on the business, and to seek to avoid any unnecessary potential delays to the Company’s programs. As of December 31, 2021, the clinical programs and research activities remain largely on track, with some modest delays in clinical trial enrollment rates and supply chain activities. While we are unable to fully quantify the potential effects of this pandemic on our future operations, including potential delays to our preclinical and clinical programs, management continues to evaluate and to seek to mitigate risks. The safety and well-being of employees, patients and partners remains our highest priority.

Centessa Pharmaceuticals plc (“Centessa” or “the Company”) is a clinical-stage pharmaceutical company with a Research & Development (“R&D”) innovation engine that aims to discover, develop and ultimately deliver impactful medicines to 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, we re-registered Centessa Pharmaceuticals Limited as an English public limited company and renamed it as Centessa Pharmaceuticals plc.

In January 2021, the management and equity holders of ApcinteX Limited, Capella Biosciences Limited, Inexia Limited, Janpix Limited, LockBody Therapeutics Ltd, Morphogen-IX Limited, Orexia Limited, Palladio Biosciences, Inc., PearlRiver Bio GmbH, Pega-One S.A.S., and Z Factor Limited (together, the “Centessa Subsidiaries”), contributed the Centessa Subsidiaries to Centessa, in a share for share exchange, after which these companies became wholly-owned subsidiaries of Centessa.

As the Company had no significant operations prior to the contribution of the Centessa Subsidiaries, and the registrant was required to present two years of historical financial statements in its prospectus filed with the SEC on June 2, 2021, the Company’s management (“Management”) sought to identify a predecessor, for which it could include audited historical financial statements, to satisfy the filing requirement. As such, Management sought to identify the predecessor from the population of portfolio companies, which would represent a sizable portion of the historical results of the entities later contributed to Centessa.

Entities affiliated with Medicxi manage multiple investment funds, including – Medicxi Ventures I LP, Medicxi Growth I LP, and Medicxi Secondary I LP. In addition, entities affiliated with Medicxi act as sub advisors to Index Ventures Life VI (Jersey) Limited which advises the managing general partner of Index Ventures Life VI (Jersey), L.P. (all funds collectively are referred to as the “Funds”). Management determined the companies owned by Index Ventures Life VI (Jersey), LP individually represent some of the earliest investments by the Funds. These companies (together, the “Centessa Predecessor Group” or the “Group”) are:

As the above entities that comprise the Centessa Predecessor Group were historically under the common control of Index Ventures Life VI (Jersey), LP, the historical financial statements of the Group for periods prior to January 30, 2021 are presented on a combined basis and are denoted as “Predecessor” within these financial statements.

Subsequent to the contribution of the Centessa Subsidiaries to Centessa, the financial activities of Centessa and all Centessa Subsidiaries are being presented on a consolidated basis and are denoted as “Successor” within these financial statements.

In June 2021, the Company completed an initial public offering (“IPO”) of its ordinary shares through the sale and issuance of 16,500,000 American Depositary Shares (“ADSs”), at an initial price of $20.00 per ADS. Each ADS represents one ordinary share with a nominal value of £0.002 per ordinary share. Following the close of the IPO, the underwriters fully exercised their option to purchase an additional 2,475,000 ADSs at the initial public offering price of $20.00 per ADS. The Company received aggregate net proceeds of $344.1 million in connection with the IPO and subsequent exercise of the underwriter’s options after deducting underwriting discounts, commissions and other offering expenses paid or to be paid.

The Group and the Company are 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 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, including the Centessa Subsidiaries’ 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 Group and the Company have incurred losses and negative cash flows from operations since inception and the Company had an accumulated deficit of $385.7 million as of December 31, 2021. The Company anticipates incurring additional losses until such time, if ever, that it can generate significant sales of the product candidates currently in development by the Centessa Subsidiaries. Substantial additional capital will be needed by the Company to fund its operations (including those of the Centessa Subsidiaries) and to develop its product candidates.

In October 2021, the Company entered into a Note Purchase Agreement with Oberland Capital Management LLC (“Oberland Capital”). Under the terms of the agreement, Oberland Capital will purchase up to $300.0 million of 6-year, interest-only (initial interest rate is 8.0% per annum), senior secured notes (the Notes) from the Company including $75.0 million, funded on October 4, 2021, $125.0 million available within 24 months at the Company’s option, and $100.0 million available to fund Mergers and Acquisitions (“M&A”), in-licensing, or other strategic transactions, at the option of the Company and Oberland Capital (See - Note 6 "Debt").

The Company expects its existing cash and cash equivalents as of December 31, 2021 of $595.1 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.

On March 10, 2020, the WHO characterized the novel COVID-19 virus as a global pandemic. The Company is continuing to proactively monitor the COVID-19 global pandemic, to assess the potential impact on the business, and to seek to avoid any unnecessary potential delays to the Company’s programs. As of December 31, 2021, the clinical programs and research activities remain largely on track, with some modest delays in clinical trial enrollment rates and supply chain activities. While we are unable to fully quantify the potential effects of this pandemic on our future operations, including potential delays to our preclinical and clinical programs, management continues to evaluate and to seek to mitigate risks. The safety and well-being of employees, patients and partners remains our highest priority.