The accompanying unaudited interim consolidated financial statements should be read in conjunction with the annual audited consolidated and combined financial statements of Centessa Pharmaceuticals plc (Successor) and the Centessa Predecessor Group (Predecessor) and related notes which can be found in our Annual Report on Form 10-K for the year ended December 31, 2022 (the “2022 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.

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:

Operating results for the Company for the three and nine months ended September 30, 2023 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 2022 as reported in the 2022 Annual Report have been omitted. Therefore, these unaudited interim consolidated financial statements should be read in conjunction with the annual audited consolidated and combined financial statements and related notes for Centessa Pharmaceuticals plc found in the Form 10-K filed with the SEC.

We are an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act (“JOBS Act”) enacted in April 2012. For so long as we remain an emerging growth company, we are permitted and intend to rely on certain exemptions from various public company reporting requirements, including not being required to have our internal control over financial reporting audited by our independent registered public accounting firm pursuant to Section 404(b) of the Sarbanes-Oxley Act of 2002, reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements, exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and any golden parachute payments not previously approved.

We will remain an emerging growth company until the earlier to occur of (1) the last day of the fiscal year that is five years following the closing of our initial public offering, (2) the last day of the fiscal year in which we have total annual gross revenues of at least $1.235 billion, (3) the last day of the fiscal year in which we are deemed to be a “large accelerated filer,” under the rules of the SEC, which means the market value of our equity securities that is held by non-affiliates exceeds $700 million as of the prior June 30th after we have been subject to the SEC’s periodic reporting requirements for at least twelve calendar months and have filed at least one annual report, and (4) the date on which we have issued more than $1.0 billion in non-convertible debt during the prior three-year period.

In addition, the JOBS Act provides that an emerging growth company can take advantage of an extended transition period for complying with new or revised accounting standards. This provision allows an emerging growth company to delay the adoption of some accounting standards until those standards would otherwise apply to private companies. We are electing to utilize the extended transition period and, as a result, will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for emerging growth companies.

We are also a “smaller reporting company” as defined in the Securities Exchange Act of 1934 (“Exchange Act”). Even after we no longer qualify as an emerging growth company, we may still qualify as a “smaller reporting company” if the market value of our ordinary shares held by non-affiliates is below $250 million (or $560 million if our annual revenue is less than $100 million) as of June 30 in any given year. As a smaller reporting company, we are eligible for scaled disclosure relief from certain Regulation S-X and Regulation S-K requirements.

The Company considers all highly liquid investments with original maturities of three months or less when purchased to be cash equivalents. Cash and cash equivalents include cash in readily available checking accounts, certificate of deposits, money market funds and U.S. Treasury securities.

The Company invests its excess cash in cash deposits, U.S. Treasury securities and SEC-registered money market funds. Securities with original maturities of three months or less when purchased are included in Cash and cash equivalents. The Company considers investments with original maturities greater than three months and remaining maturities less than one year to be short-term investments.

As of September 30, 2023, all investments in U.S. Treasury securities were classified as available-for-sale securities, which are recorded at fair value. Unrealized holding 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.

Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents and short-term investments. The Company’s cash, cash equivalents and short-term investments are held by financial institutions primarily in the United States and the United Kingdom. Amounts on deposit may at times exceed federally insured limits. Management believes that the financial institutions are financially sound, and accordingly, the Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships.

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.

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 research and development expenses, the Note Purchase Agreement, share-based compensation 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. Actual results may differ from these estimates under different assumptions or conditions.

Property and equipment are recorded at cost and are depreciated using the straight-line method over the estimated useful lives of the respective assets. Property and equipment includes computer equipment, furniture and office equipment. The costs of maintenance and repairs are expensed as incurred. Improvements and betterment that add new functionality or extend the useful life of the asset are capitalized. Depreciation expense for the nine-month periods ended September 30, 2023 and September 30, 2022 were $208 thousand and $95 thousand, respectively.

Costs related to the implementation of cloud computing arrangements that are service contracts incurred during the application development stage are capitalized and included in the same line item as a prepayment for corresponding hosting service fees. Capitalized costs are amortized over the shorter of its estimated useful life and the term of the hosting

arrangement, including anticipated extensions. Costs incurred during the preliminary project stage and the post-implementation-operation stage are expensed as incurred. Hosting fees associated with hosting as a service arrangement are expensed on a straight-line basis over the term of the hosting arrangement. Amortization expense for the nine months ended September 30, 2023 was $356 thousand.

In accordance with ASU No. 2016-02, Leases (“ASC 842”), the Company assesses whether an arrangement is a lease, or contains a lease at the inception of the arrangement. When an arrangement contains a lease, the Company categorizes leases with contractual terms longer than twelve months as either operating or finance. Finance leases are generally those leases that allow us to substantially utilize or pay for the entire asset over its estimated life. Assets acquired under finance leases are recorded in “Property and equipment, net.” All other leases are categorized as operating leases.

The Company records right-of use ("ROU") assets and lease obligations for its finance and operating leases, which are initially recognized based on the discounted future lease payments over the term of the lease. As the rate implicit in the Company's leases may not be easily determinable, the Company uses its incremental borrowing rate to calculate the present value of the sum of the lease payments. Lease terms may include options to extend or terminate the lease. The Company will include such options in determining the lease term when it is reasonably certain that the Company will exercise such options. Operating and finance lease ROU assets are recognized net of any lease prepayments and incentives. The Company elected the practical expedient to not separate lease and non-lease components and, accordingly, accounts for them as a single lease component. Operating lease expense is recognized on a straight-line basis over the lease term. Finance lease expense is recognized based on the effective-interest method over the lease term. The Company elected not to recognize ROU assets and lease obligations for any short-term leases, which are defined as leases with an initial term of 12 months or less.

Long-lived assets, comprised of property and equipment and operating lease right-of-use assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated undiscounted future cash flows, then an impairment charge is recognized for the amount by which the carrying value of the asset exceeds the estimated fair value of the asset. No impairments of long-lived assets for the nine-month periods ended September 30, 2023 and 2022 were recognized by the Company.

In October 2021, the Company entered into a Note Purchase Agreement (the “Note Purchase Agreement”) with Oberland Capital. Under the terms of the Note Purchase Agreement, Oberland Capital will purchase up to $300 million of 6.0 years, interest-only, senior secured notes (the “Notes”) from the Company including $75 million funded on October 4, 2021, $50 million available through December 2023 at the Company’s option, $75 million available through September 2024 at the Company’s option and $100 million available to fund Mergers and Acquisitions (“M&A”), in-licensing, or other strategic transactions, at the option of the Company and Oberland Capital. In addition to interest payments on the principal, the Company is obligated to pay a milestone payment upon the Company’s first product to obtain regulatory approval.

The Company evaluated the Notes and determined that the Notes include embedded derivatives that would otherwise require bifurcation as derivative liabilities. Neither the debt instrument nor any embedded features are required to be classified as equity. Therefore, the hybrid financial instrument comprised of the debt host and the embedded derivative liability may be accounted for under the fair value option. The Company elected to carry the Notes at fair value, and the debt instrument is outside the scope of ASC 480, Distinguishing Liabilities from Equity, and thus will be classified as a liability under ASC 470, Debt, in the Company’s financial statements. As the Company has elected to account for the Notes under the fair value option, debt issuance costs were immediately expensed.

The fair value of the Note Purchase Agreement represents the present value of estimated future payments, including interest, principal as well as estimated payments that are contingent upon the achievement of specified milestones. The fair value of the Notes is based on the cumulative probability of the various estimated payments. The fair value measurement is based on significant Level 3 unobservable inputs such as the probability of achieving the milestones, anticipated timelines,

probability and timing of an early redemption of all obligations under the Note Purchase Agreement and the discount rate. Any changes in the fair value of the liability in each reporting period are recognized in the consolidated statement of operations and comprehensive loss until it is settled.

Basic loss per ordinary share is computed by dividing net loss by the aggregate weighted-average number of ordinary shares outstanding. Diluted loss per ordinary share includes the effect, if any, from the potential exercise or conversion of securities, such as convertible preferred shares, stock options, unvested restricted ordinary shares and convertible debt which would result in the issuance of incremental ordinary shares. For diluted net loss per ordinary share, the weighted-average number of ordinary shares is the same for basic net loss per ordinary share due to the fact that when a net loss exists, dilutive securities are not included in the calculation as the impact is anti-dilutive.

The following potentially dilutive securities have been excluded from the computation of diluted weighted-average ordinary shares outstanding for the nine months ended September 30, 2023 and September 30, 2022, as they would be anti-dilutive: