Immunocore Holdings plc

Consolidated Notes to the Financial Statements

1. Description of business

Immunocore Holdings plc (collectively with its subsidiaries, the “Company”) is a public limited company incorporated in England and Wales and has the following wholly owned subsidiaries: Immunocore Limited, Immunocore LLC, Immunocore Commercial LLC, Immunocore Ireland Limited, Immunocore GmbH, and Immunocore Nominees Limited with operations based primarily in the United Kingdom and United States. The Company is pioneering and delivering transformative immunomodulating medicines to radically improve outcomes for patients with cancer, infectious diseases, and autoimmune diseases. Leveraging its proprietary, flexible, off-the-shelf ImmTAX (Immunem obilizingm onoclonal TCRs Against X disease) platform, the Company’s pipeline includes clinical and preclinical programs in oncology, infectious diseases, and autoimmune diseases.

In January and April 2022, the Company received approval from the U.S. Food and Drug Administration ("FDA") and European Commission, ("EC"), respectively, for its lead product, KIMMTRAK, for the treatment of unresectable or metastatic uveal melanoma. The Company has subsequently received approvals in further territories, and continues to launch and seek approvals in additional territories. KIMMTRAK is now approved in 39 countries and the Company has commercially launched the product in 30 countries, including the United States, Germany and France, among other territories.

2. Summary of significant accounting policies

Basis of presentation

The Company’s consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States ("U.S. GAAP") for the fiscal years ended December 31, 2025, 2024, and 2023 and include the financial results of all wholly-owned subsidiaries. Intercompany transactions and balances have been eliminated upon consolidation and the consolidated financial statements are presented in U.S. dollars.

Use of estimates

The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make judgments, estimates and assumptions. These judgments, estimates and assumptions affect the reported assets and liabilities as well as income and expenses in the financial period.

The estimates and associated assumptions are based on information available when the consolidated financial statements are prepared, historical experience and various other factors which are believed to be reasonable under the circumstances, the results of which form the basis of making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources.

Existing circumstances and assumptions about future developments, however, may change due to market changes or circumstances arising that are beyond the Company’s control. Actual results could differ from those estimates. Estimates are primarily made in relation to revenue recognition, operating lease incremental borrowing rates, share-based compensation expense, clinical accruals and deferred tax asset valuation allowances.

Foreign currencies

The reporting currency of the Company is the U.S. dollar. Effective January 1, 2024, the Company’s ultimate parent adopted the U.S. dollar as its functional currency. Prior to January 1, 2024, the functional currency of the Company’s ultimate parent was the British pound sterling. The functional currency of the Company’s ultimate parent and each subsidiary is based on the currency of the economic environment in which they operate. The change in functional currency of the Company’s ultimate parent is due to a change in the economic facts and circumstances of the entity due to the increased exposure to the U.S. dollar primarily as a result of the increased cash flows related to financing and investing activities that are now expected to occur going forward in this entity. The effect of the change in functional currency for the Company’s ultimate parent was applied prospectively in the Consolidated Financial Statements effective January 1, 2024.

Upon consolidation, assets and liabilities of each subsidiary with a functional currency that differs to the Company’s ultimate parent are translated into U.S. dollars at period-end exchange rates, and revenues and expenses are translated into U.S. dollars using average exchange rates for each reporting period. Translation adjustments are reflected as other comprehensive income (loss).

Revenues

Pursuant to Accounting Standards Codification Topic 606 ("ASC 606"), the Company recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To determine revenue recognition for agreements, the Company performs the following five steps: (i) identifying the contract with a customer, (ii) identifying the performance obligations in the contract, (iii) determining the transaction price, (iv) allocating the transaction price to the performance obligations, and (v) recognizing revenue when, or as, an entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration to which it is entitled in exchange for the goods or services it transfers to the customer.

At contract inception, the Company identifies the goods or services promised within each contract, assesses whether each promised good or service is distinct and determines those that are performance obligations. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when the performance obligation is satisfied.

Revenue from sale of therapies, net relates to the sale of KIMMTRAK following marketing approval and the sale of tebentafusp under a compassionate use and an early access program in France up to September 2022. The Company recognizes revenue at the point in time that control transfers to a customer, which is typically on delivery. The Company also operates under consignment arrangements where control passes when the Company’s distributors take KIMMTRAK out of consignment inventory. The amount of revenue recognized under its arrangements reflects the consideration to which the Company expects to be entitled, net of estimated deductions for rebates, chargebacks and product returns. Estimated revenue deductions are updated at the end of each reporting period using the latest available data. The Company considers whether any part of amounts expected to be received should be constrained to ensure that it is probable that a significant reversal in the cumulative revenue recognized will not occur.

Rebates: Rebates consist of Medicaid and other governmental rebates in the U.S. and other similar programs in Europe. These reserves are recorded as a reduction to revenue in the same period the related revenue is recognized. The Company's estimates are based on current pricing and historical data, updated at each reporting period to reflect actual claims received. For markets where the price is open to negotiation, judgments are made in line with expected pricing outcomes.

Chargebacks: Chargebacks for discounts represent the Company’s estimated obligations resulting from contractual commitments for specialty distributors to sell KIMMTRAK to qualifying hospitals at a lower price. For such sales, the specialty distributors charge back the difference between the wholesale acquisition cost and this lower price. The Company estimates chargeback deductions by analyzing sell-through data relating to the hospital mix of onward sales made by specialty distributors.

Product returns: The Company estimates the amount of its product sales that may be returned by its customers and records this in the period the related revenue is recognized. The Company bases product return liabilities on quantitative information provided by the Company’s distributors.

The Company’s main customers in the United States and Europe are its distributors. These distributors are invoiced at contractual list prices with standard payment terms typically betweenone andtwo months. When the Company has the right to offset chargebacks against accounts receivable and the parties have agreed to settle the payments net, chargebacks are recorded as a reduction in accounts receivable. Other chargebacks, rebates and deductions are recognized in Accrued expenses and other current liabilities in the Consolidated Balance Sheets.

In certain countries, the Company’s customers are hospitals and healthcare providers, where KIMMTRAK is sold through an agent acting on the Company’s behalf. Revenue from sale of therapies, net also includes amounts for partnered revenue, which is recognized on delivery and transfer of title to Medison Pharma Ltd ("Medison") and Er-Kim Pharmaceuticals Bulgaria EOOD ("Er-Kim") the Company’s exclusive distributors in certain countries outside the United States. From December 31, 2025, we have combined Product revenue, net and Pre-product revenue, net into Revenue from sale of therapies, net in order to simplify our presentation.

Collaboration revenue

The Company analyzes its collaboration agreements to assess whether they are within the scope of ASC Topic 808, Collaborative Arrangements (“ASC 808”) to determine whether such arrangements involve joint operating activities performed by parties that are both active participants and are exposed to significant risks and rewards that are dependent on the commercial success of such activities. It was determined that the Company's historical collaboration agreements were not in the scope of ASC 808. The Company concluded that all aspects of the arrangements represented a transaction with a customer, and therefore, were accounted for within the scope of ASC 606. Pursuant to ASC 606, a customer is a party that has contracted with an entity to obtain goods or services that are an output of the entity’s ordinary activities in exchange for consideration. An entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. The Company determines the units of account within the collaboration agreement utilizing the guidance in ASC 606 to determine which promised goods or services are distinct. In order for a promised good or service to be considered distinct under ASC 606, the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (i.e., the good or service is capable of being distinct), and the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (i.e., the promise to transfer the good or service is distinct within the context of the contract).

Under its historical collaboration agreements, the Company granted rights to technology with respect to the development of specified targets and the commercialization of future product candidates for such targets. In addition, the Company was required to perform R&D services, participate on a joint steering committee and the agreements also provided parties with the option to obtain exclusive rights to the associated intellectual property license. The Company assesses whether each promised good or service is distinct for the purpose of identifying the performance obligations in the contract. The Company determined that these promises represented specialized, combined performance obligations, which were satisfied over time. Further, the Company determined that their collaborators cannot benefit from the intellectual property licenses separately from the R&D activities and participation on the joint steering committee because these services are specialized and rely on the Company’s expertise such that these activities are highly interrelated and therefore not distinct.

The Company estimates the transaction price based on the amount it expects to be entitled to for transferring the promised goods or services in the contract and may include fixed and variable consideration. At the inception of each arrangement that includes variable consideration, the Company evaluates the amount of potential payment and the likelihood that the underlying constraint will be released. Variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur in a future period.

Revenue is recognized using an estimate of percentage completion which takes into consideration the estimated timelines required to satisfy the performance obligation and the time taken since program nomination.

Deferred revenue

The Company’s deferred revenue as of December 31, 2025 and 2024 is related to a revenue partnership with Medison relating to the supply and distribution of KIMMTRAK and will be classified within revenue from sale of therapies, net in accordance with ASC 606. The Company’s deferred revenue relates to a non-refundable upfront receipt from Medison under an amended agreement entered into in November 2022. The Company determined that this receipt relates to the distribution of KIMMTRAK in South America and assessed that the Company has a single performance obligation to provide KIMMTRAK to Medison for onward sale under an exclusive distribution license. The deferred revenue is expected to be released with the sale of products following regulatory approval in the territory.

Accounts receivable

Accounts receivable includes amounts invoiced or contractually accrued where only the passage of time is required before payment is received under the Company’s revenue arrangements. Such receivables principally relate to KIMMTRAK sales. An allowance for lifetime expected credit losses on accounts receivable is measured using historical credit loss experience, conditions at the end of each reporting period, and reasonable and supportable forecasts that affect collectability. Expected credit losses at the end of December 31, 2025 and 2024 were immaterial.

Inventory

Inventory includes KIMMTRAK manufactured for commercial sale, items in the process of being manufactured for sale, and materials to be used in the manufacturing process for such sale. The principal costs in manufacturing the Company’s inventory are raw materials, external manufacturing costs, and other costs incurred in bringing inventory to its location and condition prior to sale.

Inventory is recorded at weighted average cost and presented as an asset in the Consolidated Balance Sheets at the lower of cost and net realizable value. The Company assesses whether an expense should be recognized as a result of writing down inventory values at each reporting period for excess or obsolete inventory at risk of expiry. Such expenses are recorded as a component of Cost of revenue from sale of therapies in the Consolidated Statements of Operations and Comprehensive Loss in the period during which they are first identified.

The Company records inventory costs for potential products within R&D expenses until regulatory approval is considered probable, after which, the Company capitalizes subsequent costs related to the production of inventories. Certain inventory can be used for clinical purposes or for commercial products, and the Company records such items within R&D expenses at the point that the vials are assigned for clinical use.

Cost of revenue from sale of therapies

Cost of revenue from sale of therapies represents production costs including raw materials, external manufacturing costs, and other costs incurred in bringing inventory to its location and condition prior to sale. Overheads and internal costs of revenue from sale of therapies are minimal under the Company's manufacturing arrangements. Cost of revenue from sale of therapies may also include write-off costs and provisions related to excess or obsolete inventory.

Research and development ("R&D") expense

R&D costs are expensed as incurred and include (i) employee-related expenses, including salaries, benefits, travel and share-based compensation expense for employees engaged in R&D functions; (ii) external R&D expenses incurred under arrangements with third parties, such as contract research organization ("CRO") agreements, investigational sites and consultants; (iii) the cost of acquiring, developing and manufacturing clinical study materials, including the cost of consultants and contract manufacturing organization ("CMO"); (iv) costs associated with preclinical and clinical activities and regulatory operations; (v) costs incurred in development of intellectual property, (vi) and depreciation and R&D facilities costs.

The Company estimates accrued expenses at each balance sheet date based on facts and circumstances known at that time. These estimates are based on reviews of open contracts, reports provided by the CROs and CMOs and internal reviews to estimate the level of service performed and the associated cost incurred for those services when the Company has not yet been invoiced or otherwise notified of the actual cost. In accruing clinical trial expenses, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate made, the expense is adjusted accordingly. Where payments made to CROs or other parties exceed the level of services provided, a prepayment is recorded in the Consolidated Balance Sheets.

Share-based compensation

The Company operates equity-settled, share-based compensation plans whereby employees and directors are granted restricted share units ("RSUs") or options to purchase shares in the Company. The fair value of grants is expensed over the vesting period, which is the period in which the services are received. The majority of the Company’s awards have graded vesting schedules, and the expense for these awards is recognized over the requisite service period for each separate vesting portion as if the grant, in substance, represented multiple awards. The grant date fair value of RSUs is based on the market value of our shares on the date of grant. The grant date fair value of options is calculated using the Black Scholes valuation model.

Estimation of the fair value of options requires judgment, including assumptions about the expected term of share-based options and expected volatility, which are used to determine the fair value of the Company’s options granted. The expected term is based on the Company’s assessment of the period within which participants are expected to exercise options, which requires consideration of employee groups, expected employee service, and other internal factors, and the degree to which these are expected to shorten the term of options in comparison to contractual expiry dates. Estimated expected volatility is based on the Company’s share price volatility since its initial public offering. The expected volatility reflects the assumption that the historical volatility over a period similar to the life of the awards is indicative of future trends, which may not necessarily be the actual outcome.

The Company assumes no dividend payments for the purposes of estimating fair value and uses a zero-coupon U.S. Treasury yield curve applicable for the period of the expected term to form an estimate of the risk-free rate.

Forfeitures expected to occur for options and RSUs are estimated by considering both market and company-specific data and the available internal information at the end of each reporting period.

Income tax

Income tax includes components of current and deferred tax and is recognized in the Consolidated Statements of Operations and Comprehensive Loss.

Current tax is the expected tax payable or receivable on the taxable income or loss for the current or prior periods using tax rates enacted at the balance sheet date.

Deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the financial statement carrying amount and the tax bases of assets and liabilities at the applicable tax rates and for operating loss and tax credit carryforwards. A valuation allowance reduces deferred tax assets in the Consolidated Balance Sheets to reflect the amount that is more likely than not to be realized. The Company evaluates the realizability of its deferred tax assets at each reporting period and adjusts the valuation allowance accordingly, considering income forecasts, availability of carrybacks, taxable temporary differences and other factors affecting the realization of deferred tax assets.

The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. As of December 31, 2025 and 2024, the Company has not recorded any provision for uncertain tax positions.

Changes in the Company’s estimate of income tax positions relating to the more-likely-than-not threshold are recognized in the first subsequent period following the threshold being met or ceasing to be met.

R&D expenditure credits

The Company receives R&D expenditure credits to compensate for its research activities, which are recognized when it is more likely than not the Company will meet the terms for receiving and realizing the benefit of the credits. Recognition is on a systematic basis over the periods in which the Company recognizes costs for which the credits are intended to compensate (i.e., qualified expenses).

The Company benefits in the United Kingdom from His Majesty’s Revenue & Customs (“HMRC”) R&D Expenditure Credit (“RDEC”), which provides relief against U.K. corporation tax. Based on criteria established by HMRC, a portion of the Company’s expenditures incurred on R&D activities are eligible for RDEC relief. The Company recognizes the benefit as a reduction of the related R&D expenses on the Consolidated Statements of Operations and Comprehensive Loss.

Leases

The Company assesses whether contracts represent or contain leases at inception by determining whether the Company has the right to use, or control the use of, an identified asset from which it can obtain substantially all the economic benefits for a defined period.

The Company leases its corporate headquarters in the United Kingdom, where its facilities contain R&D, laboratory and office space of approximately 123,000 square feet. In addition, the Company leases approximately 45,000 square feet of office space in the United States, and small offices in Ireland and Switzerland. The leases in the United Kingdom expire between 2037 and 2043. Estimates of the term consider non-cancellable periods and include options to extend or terminate the lease when it is reasonably certain that the Company will exercise such options.

Operating lease right-of-use assets and liabilities are recognized at the lease commencement date. Right-of-use assets are initially measured at cost, representing the initial amount of the lease liability and any initial direct costs incurred, with a reduction for any lease incentives received. Lease liabilities are initially measured at the present value of the lease payments.

Since the rate implicit in leases is not readily determinable, the Company uses available information to determine its incremental borrowing rates, which represent the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term for an amount equal to the lease payments in a similar economic environment.

Fixed lease components include rental payments at inception and termination costs for leases not reasonably certain of extension. Such components are accounted for as part of the right-of-use assets and lease liabilities and recognized on a straight-line basis over the lease term. Variable lease components include subsequent indexation-related rental increases. If such variable components do not coincide with a remeasurement of the lease term, the additional costs are recorded as a variable component of the lease expense in the Consolidated Statements of Operations and Comprehensive Loss as incurred. Non-lease components such as maintenance costs and service charges are separated from lease components and recognized separately in the Consolidated Statements of Operations and Comprehensive Loss.

Operating lease costs are allocated to R&D and Selling, general and administrative ("SG&A") expenses in the Consolidated Statements of Operations and Comprehensive Loss. The related lease cash flows are categorized under Net cash used in operating activities in the Consolidated Statements of Cash Flows. The Company elects not to recognize right-of-use assets and lease liabilities for short-term leases with a term of 12 months or less containing no repurchase options reasonably certain of exercise, and the expense for these short-term leases is immaterial. The Company does not have financing leases.

Property and equipment

Property and equipment are stated at cost net of accumulated depreciation and impairment losses. The Company expenses repairs and maintenance related to property and equipment in the Consolidated Statements of Operations and Comprehensive Loss when the costs are incurred.

Depreciation is charged to the Consolidated Statements of Operations and Comprehensive Loss on a straight-line basis over the estimated useful lives of assets as follows:

Impairment of long-lived assets

The Company assesses whether circumstances indicate that the estimated remaining useful life of its long-lived assets should be changed or that the carrying value of such assets may be impaired. The Company didnot identify any such circumstances or recognize any impairment charges for the years ended December 31, 2025,2024 and 2023.

Cash and cash equivalents

Cash and cash equivalents comprise cash balances and short-term money market funds with an original maturity of less than three months. Money market funds are presented at fair value in the Consolidated Balance Sheets.

Marketable securities

Marketable securities consist of investment funds which are measured and reported at fair value determined using quoted market prices. The investment funds are primarily invested in U.S. investment-grade debt securities, including asset-backed and mortgage-backed securities. Marketable securities are available to the Company for use in current operations and are classified as current assets. Gains and losses from marketable securities are recognized in Other income (expense), net.

Concentrations of credit risk and off-balance sheet risk

Financial instruments that potentially subject the Company to concentrations of credit risk are accounts receivable, cash equivalents, marketable securities and deposits held with banks and financial institutions. Cash, cash equivalents, marketable securities and deposits are maintained with high-quality financial institutions in Europe and the United States. The Company has not experienced any credit losses with such institutions and has incurred an immaterial amount of losses in relation to its accounts receivable from customers. The Company has no financial instruments with off-balance sheet risk of loss. As of December 31, 2025 and 2024, the amounts of expected credit losses recognized in the Consolidated Balance Sheets were not material.

Interest-bearing loans and borrowings

The Company issued 2.5% Convertible Senior Notes due in 2030 in February 2024 (the "Notes"), and evaluated to determine whether they contain features that qualify as embedded derivatives in accordance with ASC 815. Embedded derivatives must be separately measured from the host contract if all the requirements for bifurcation are met. The assessment of the conditions surrounding the bifurcation of embedded derivatives depends on the nature of the host contract and the features of the derivatives. In accounting for the issuance of the Notes, the Company treats the instrument wholly as a liability, in accordance with ASC 470, as the conversion features do not require bifurcation as a derivative in accordance with ASC 815 and the Notes were not issued at a substantial premium.

The Company offsets issuance costs against the initial value of the debt on the Company’s Consolidated Balance Sheets and amortizes the costs over the loan term using the effective interest method. Such costs are recognized under Interest expense in the Consolidated Statements of Operations and Comprehensive Loss.

Fair value measurements

Where financial and non-financial assets and liabilities are measured at fair value, the Company uses appropriate valuation techniques for which sufficient data are available, maximizing the use of relevant observable inputs and minimizing the use of unobservable inputs.

Fair values are categorized into different levels in a fair value hierarchy based on the inputs used in the valuation techniques as follows:

•Level 1: quoted prices (unadjusted) in active markets for identical assets or liabilities.

•Level 2: inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly (i.e., as prices) or indirectly (i.e., derived from prices).

•Level 3: inputs for the asset or liability that are not based on observable market data (unobservable inputs), and that are significant to the fair value of the assets or liabilities.

As of December 31, 2025 and 2024, the Company held $366.8 million and $338.1 million, respectively, of money market funds required to be measured at fair value on a recurring basis within cash and cash equivalents. In addition, as of December 31, 2025 and 2024, the Company held $396.4 million and $364.6 million, of marketable securities, respectively, including unrealized gains of $19.7 million and $14.6 million, respectively. The fair value of these cash equivalents and marketable securities is based on quoted prices from active markets (Level 1 inputs). The Company recognizes transfers between levels of the fair value hierarchy at the end of the reporting period during which the changes have occurred. There wereno transfers between levels of fair value hierarchy in the years ended December 31, 2025 and 2024. Other financial instruments, although not recorded at fair value on a recurring basis, include cash, accounts receivable, accounts payable and interest-bearing loans and borrowings.

On November 8, 2024, the Company, repaid in full the loan outstanding under the Pharmakon Loan Agreement. The fair value of borrowings under the Notes and Pharmakon Loan Agreement (disclosed in Note 7. “Non-current interest-bearing loans and borrowings”) were based on Level 2 inputs, which include observable inputs estimated using discounted cash flows and market-based expectations for interest rates, credit risk, and the contractual terms of debt instruments. After initial recognition, borrowings are measured at amortized cost using the effective interest method.

Net loss per share

Basic and diluted net loss per share is calculated by dividing the net loss for the period by the weighted average number of ordinary shares outstanding during the period. The dilutive effect of potential ordinary shares through share options, RSUs and the Notes are considered to be anti-dilutive as they would decrease the net loss per share and are therefore excluded from the calculation of diluted net loss per share.

Recently issued and recently adopted accounting pronouncements

In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures. This ASU improves the transparency of income tax disclosure by requiring consistent categories and greater disaggregation of information in the rate reconciliation, and income taxes paid disaggregated by jurisdiction. This guidance is effective for the Company for the year beginning January 1, 2025. The Company adopted this ASU for the annual period ended December 31, 2025 and the amendments have been applied retrospectively to all prior periods presented in the financial statements by expanding the Company's income tax disclosure in Note 12. "Income Taxes."

In November 2024, the FASB issued ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40). This ASU requires disclosure in the notes to the financial statements, at each interim and annual reporting period, of specified information about certain costs and expenses including purchases of inventory, employee compensation, depreciation and intangible asset amortization included in each relevant expense caption. Also required is a qualitative description of the amounts remaining in relevant expense captions that are not separately disaggregated. This ASU is effective for all public entities for annual reporting periods beginning after December 15, 2026, and interim periods within annual reporting periods beginning after December 15, 2027, and early adoption is permitted. This ASU should be applied either prospectively to financial statements issued after the effective date of this update or retrospectively to all prior periods presented in the financial statements. The Company is currently evaluating these new disclosure requirements and the impact of adoption on its financial statements.

3. Revenue

During the year ended December 31, 2025, the Company recognized $400.0 million (2024: $310.0 million, 2023: $238.7 million) of net revenue from sale of therapies, relating to the sale of KIMMTRAK, primarily in the United States and Europe, after estimated deductions for rebates, chargebacks and returns, which are recognized in Accrued expenses and other current liabilities, as set out in the Company’s accounting policies.

The Company recognized revenues from four customers accounting for 23%,23%,17% and 18% of the Company’s revenue from sale of therapies, net for the year ended December 31, 2025, four customers accounting for 29%,27%,18%, and 17% of the Company’s revenue from sale of therapies, net for the year ended December 31, 2024, and four customers accounting for 29%,26%,17%, and 16% and of the Company’s revenue from sale of therapies, net for the year ended December 31, 2023.

Revenue from sale of therapies, net is presented by country / region based on the location of the end customer below (in thousands):

Revenue from sale of therapies, net for the year ended December 31, 2025 includes $25.9 million (2024: $13.7 million, 2023: $3.6 million), of partnered revenue pursuant to the Company's separate agreements with Medison Pharma Ltd, ("Medison"), and Er-Kim Pharmaceuticals Bulgaria EOOD ("Er-Kim"). Revenue from these agreements is allocated between the Company's European and international markets.

Accounts receivable from contracts with customers

Accounts receivable as of December 31, 2025 and 2024 were as follows (in thousands):

As of December 31, 2025, four customers individually accounted for approximately 20%,18%,20% and 16% of accounts receivable associated with the Company’s net revenue from sale of therapies, as compared to 22%,22%,20% and 15% as of December 31, 2024. An allowance for lifetime expected credit losses on accounts receivable is measured using historical credit loss experience, conditions at the end of each reporting period, and reasonable and supportable forecasts that affect collectability. Expected credit losses as of December 31, 2025 and 2024 were immaterial.

Accruals for rebates and chargebacks

Current and non-current accruals for rebates, chargebacks and returns as of December 31, 2025 and 2024 were as follows (in thousands):

The adjustments related to prior period sales in the year ended December 31, 2025 were due to changes in estimates primarily related to European pricing negotiations.

Deferred revenue

For the year ended December 31, 2025, there was $0.4 million revenue recognized that was included in Deferred revenue as of January 1, 2025 (2024: $0; 2023: $7.8 million).

Deferred revenue in the Consolidated Balance Sheets is primarily in respect of the upfront fee and development milestone consideration received from collaboration agreements in advance of services performed by the Company.

Non-current deferred revenue in the Consolidated Balance Sheets as of December 31, 2025, relates to a revised distribution agreement with Medison entered into in November 2022. Under the revised agreement, the Company received a non-refundable payment of $5.0 million in exchange for granting Medison exclusive distribution rights in South America. The Company has determined that the deferred revenue relates to the Company’s single, combined performance obligation to supply KIMMTRAK to Medison and to grant Medison the exclusive right to distribute KIMMTRAK in South America. The revenue will be recognized on a straight-line basis over the term of the contract of 10 years from the date of the first commercial sale in the territory. Following the first commercial sale in the territory during the three months ended June 30, 2025, the Company began recognizing this revenue within net revenue from sale of therapies and consequently the Company reclassified the portion of deferred revenue expected to be recognized over the next twelve months as current.

Genentech Collaboration

Under the Genentech agreement signed in November 2018, the Company received aggregate non-refundable payments totaling $100 million consisting of an initial upfront payment of $50 million and $50 million paid upon an investigational new drug filing for the first clinical trial of the product candidate compound, in exchange for granting Genentech rights to co- develop/co-promote the Company’s IMC-C103C program and the co-exclusive worldwide license to the Company’s intellectual property rights in MAGE A4 soluble TCR bispecific therapeutic candidate compounds. The Company was responsible for development of the IMC-C103C program over the period of time to estimated completion of the Phase 1 clinical trial, with costs being shared equally with Genentech.

In February 2023, as the Company elected to withdraw from co-funding with Genentech the MAGE-A4 HLA-A02 program, IMC-C103C, Genentech acquired an exclusive worldwide license to the MAGE-A4 HLA-A02 soluble TCR bispecific therapeutic candidate compounds and shall be fully responsible for all further development and commercialization of such candidate compounds, at its expense.

The transaction price was recorded as deferred revenue on receipt in November 2018 and allocated to a single combined performance obligation covering the granting of the co-exclusive worldwide license, the provision of development services and participation on a joint steering committee. This deferred revenue is recognized as the Company satisfies the combined performance obligation over the estimated period of time to when the Company has completed substantially all of its responsibilities associated with its withdrawal from the co-funding and the Phase 1 clinical trial. R&D costs reimbursed under the 2018 Genentech Agreement are considered variable consideration and not recognized in the transaction price until it is probable that the recognition of such revenue will not be reversed.

During the year ended December 31, 2025, the Company recognizedno revenue relating to the 2018 Genentech Agreement (2024: $0.2 million; 2023: $10.7 million). The revenue recognized represents both deductions from deferred revenue and R&D costs reimbursed, predominantly for clinical trial costs. Such reimbursements arise in order to ensure that R&D costs are shared equally in accordance with the 2018 Genentech agreement. As of December 31, 2023, the Company determined its performance obligation under its collaboration with Genentech was complete. If MAGE-A4 HLA-A02 targeted products are commercialized, the Company would be eligible to receive development and commercial milestone payments plus royalties from Genentech on any sales of MAGE-A4 HLA-A02 targeted products arising under the Genentech Agreement. The Company determined achieving commercialization milestones and royalties to be unlikely and were excluded from the transaction price as of December 31, 2025,2024 and 2023; therefore, any future milestones will be recorded when they become probable of being achieved.

Bristol-Myers Squibb ("BMS") Collaboration

In February 2024, we entered into a clinical trial collaboration and supply agreement with BMS (the "BMS Agreement") to investigate our ImmTAC bispecific TCR candidate targeting PRAME HLA-A*02:01, brenetafusp, in combination with BMS’s nivolumab, in first-line advanced cutaneous melanoma. Under the terms of the BMS Agreement, we are sponsoring and funding the registrational Phase 3 clinical trial of brenetafusp in combination with nivolumab in first-line advanced cutaneous melanoma (PRISM-MEL-301), and BMS is providing nivolumab. No monetary consideration is transferred as a result of the BMS Agreement.

4. Prepaid expenses and other current assets

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

Included within other current assets are amounts paid in advance to clinical research organizations that are expected to be received through services rendered or repaid within 12 months.

5. Property and equipment, net

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

Depreciation expense for the years ended December 2025,2024 and 2023 was $3.1 million, $4.2 million and $4.1 million, respectively.

6. Accrued expenses and other current liabilities

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

See Note 3. “Revenue” for a breakdown of rebates, chargebacks and returns.

Clinical accruals primarily represent unbilled work undertaken by CROs as part of the advancement of the Company's clinical programs.

7. Interest-bearing loans and borrowings

Non-current interest-bearing loans and borrowings consisted of the following as of December 31, 2025 (in thousands):

Non-current interest-bearing loans and borrowings consisted of the following as of December 31, 2024 (in thousands):

Interest expense consisted of the following (in thousands):

Convertible senior notes

On February 2, 2024, the Company completed a private offering (the "Offering") of $402.5 million aggregate principal amount of Notes, including the exercise in full of the initial purchasers’ option to purchase up to an additional $52.5 million principal amount of Notes. The Notes were issued pursuant to an indenture, dated February 2, 2024, as supplemented on March 17, 2025 (the "Indenture"), between the Company and U.S. Bank Trust Company, National Association, as trustee. The Company’s net proceeds from the Offering of the Notes were $389.1 million, after deducting issuance costs of $13.4 million.

The Notes are senior, unsecured obligations of the Company and will mature on February 1, 2030, unless earlier converted, redeemed or repurchased. The Notes will accrue interest payable semi-annually in arrears on February 1 and August 1 of each year, beginning on August 1, 2024, at a rate of 2.50% per year.

Issuance costs incurred with the Notes were $13.4 million and are being amortized as interest expense on an effective interest rate method over the expected life of the Notes, through February 2030, at an effective interest rate of 3.06%.

Holders may convert all or any portion of their Notes at their option at any time prior to the close of business on the business day immediately preceding the maturity date into American Depositary Shares ("ADSs") of the Company. The Notes have an initial conversion rate of 10.5601 ADSs per $1,000 principal amount of the Notes, which will be subject to anti-dilution adjustments in certain circumstances. This represented an initial conversion price of $94.70 per ADS. The number of shares that would be issuable assuming conversion of all of the Notes is 5,950,600 (assuming the maximum increase to the conversion rate in connection with a “make-whole fundamental change” (as defined in the Indenture)). Following certain corporate events that occur prior to the maturity date of the Notes or if the Company delivers a notice of optional redemption or a notice of tax redemption, the Company shall, in certain circumstances, increase the conversion rate for a holder of the Notes who elects to convert its notes in connection with such a corporate event or convert its notes called (or deemed called) for redemption in connection with such notice of optional redemption or notice of tax redemption, as the case may be.

The Company may not redeem the Notes prior to February 5, 2027, except in the event of certain tax law changes as described below and in the Indenture. The Company may redeem for cash all or any portion of the Notes (subject to the partial redemption limitation described in the Indenture), at its option, on or after February 5, 2027 if the last reported sale price of the ADSs has been at least 130% of the conversion price for the Notes then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which the Company provides notice of optional redemption, at a redemption price equal to 100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the optional redemption date.

If, as a result of certain changes in the law of any relevant tax jurisdiction, the Company would be required to pay additional amounts (as defined in the Indenture) on the Notes, the Company may redeem the Notes in whole, but not in part, at a tax redemption price of 100% of the aggregate principal amount thereof, plus accrued and unpaid interest to, but excluding, the tax redemption date and all additional amounts, if any, which otherwise would be payable to the date of tax redemption. Upon the Company giving notice of a tax redemption, a holder may elect not to have its Notes redeemed, in which case the holder would not be entitled to receive any additional amounts with respect to its Notes after the tax redemption date.

If the Company undergoes a fundamental change, holders may require the Company to repurchase for cash all or any portion of their Notes at a repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date.

Pharmakon loan

On November 8, 2022, the Company entered into the Pharmakon loan agreement (the "Pharmakon Loan Agreement"), providing for term loans to the Company in an aggregate principal amount of up to $100 million to be funded intwo tranches. The first tranche of $50 million bore interest at a fixed rate of 9.75%, which was payable quarterly in arrears, with payments commencing in 2023. The Company was also required to pay a further fee of $1.25 million at the latest by June 2024, regardless of whether it elected to draw down on the second $50 million tranche under the Pharmakon Loan Agreement. The Company elected not to exercise the option to draw down the second tranche and made the payment of $1.25 million in June 2024.

On November 8, 2024, the Company repaid in full the loan outstanding under the Pharmakon Loan Agreement resulting in a loss on extinguishment of $3.9 million. The aggregate cash payment to terminate the Pharmakon Loan Agreement was$52.1 million and consisted of$50.0 million for principal,$0.5 million accrued interest and$1.6 million attributable to a prepayment premium and other expenses payable by the Company pursuant to the Pharmakon Loan Agreement. The contractual maturity date of the loan under the Pharmakon Loan Agreement was November 8, 2028. As of December 31, 2023, the fair value of the loan was $46.1 million. These values were determined based on prevailing interest rates as of the balance sheet dates and are classified as Level 2 within the fair value hierarchy.

8. Leases

The Company’s costs as a lessee for the years ended December 31, 2025,2024 and 2023 were as follows (in thousands):

Supplemental cash flow information related to leases for the years ended December 31, 2025,2024 and 2023 were as follows (in thousands):

The weighted average remaining lease term and weighted average discount rate of operating leases at December 31, 2025 and 2024 were as follows:

The maturities of operating lease liabilities as of December 31, 2025 are as follows (in thousands):

Future lease commitments - leases not yet commenced

The Company has entered into a non-cancellable lease agreement for premises that will commence in 2028 and end in 2031, with total future minimum lease payments of approximately$3.0 million. This amount is not included in the maturities of operating lease liabilities above as the lease had not commenced as of December 31, 2025.

Lease commencement during the period

During the year ended December 31, 2025, the Company commenced a new operating lease and recognized a non‑cash right‑of‑use asset of $1.2 million and a corresponding operating lease liability of $1.4 million. The difference between the right‑of‑use asset and the lease liability primarily reflects a lease incentive, which reduces the initial carrying amount of the related right‑of‑use asset.

9. Shareholders’ equity

The Company had 50,689,271 and 50,064,860 ordinary shares issued and outstanding as of December 31, 2025 and 2024, respectively, with a par value of £0.002 per share. In addition there are 5,793,501 deferred shares as of December 31, 2025 and 2024 with a par value of £0.0001 per share. The Company has reserved 6,172,915 authorized shares for future issuance under the Equity Incentive Plan (“EIP”). See Note 10 “Share-based compensation” for a description of the EIP.

Included within ordinary shares at December 31, 2025 and 2024 are 734,397 of ordinary shares with no voting rights, respectively. All ordinary shares are entitled to receive dividends and assets available for distribution. Deferred shares have no voting rights, are not entitled to dividends and are only entitled to receive amounts paid up on the deferred shares out of assets available for distribution after all payments have been made to holders of ordinary shares for amounts paid up or payable on such shares. No dividends were paid or declared in the years ended December 31, 2025 and 2024.

On May 15, 2025, the Company passed an ordinary resolution which authorizes the directors, or any duly authorized committee of the directors, to allot shares in the Company or grant rights to subscribe for or convert any security into shares in the Company up to an aggregate nominal value of £150,000 for afive year period ending on May 14, 2030. This amount may be renewed, varied or revoked by the Company in a general meeting.

10. Share-based compensation

The following table shows the total share-based compensation expense recorded in the Consolidated Statements of Operations and Comprehensive Loss (in thousands):

Equity Incentive Plan

Under the Company’s Equity Incentive Plan ("EIP"), the Company may grant market value options, share appreciation rights or restricted shares, restricted share units ("RSUs"), performance share units and other share-based awards to the Company’s employees. The Company’s board members and consultants are eligible to receive awards under the Company’s non-employee sub-plan to the EIP. Awards may be granted at such times as the Company may determine, but will generally be granted annually following the end of the financial year. Awards vest at such times and as specified in the award agreement, typically being over afour-year period although the Company retains the discretion to provide for other vesting schedules. If the participant violates the non-competition, non-solicitation, confidentiality or other similar restrictive covenant provisions of any employment contract, the right of the participant to receive these shares on vesting shall terminate immediately. The Company maintains discretion over the type and terms of equity awards granted. Share options lapse on thetenth anniversary from the date of grant, and they are not subject to performance conditions or entitled to dividends. As of December 31, 2025, the Company has reserved 6,172,915 authorized shares for future issuance under the EIP.

During the years ended December 31, 2025 and 2024, options over a total of 1,793,514 shares and 1,062,745 shares respectively were awarded under the Company’s EIP. Of the above awards in the year ended December 31, 2025, there were 207,829 options awarded to the Company's non-executive directors,183,386 of which vest on the first anniversary from the date of grant and 24,443 of which vest monthly over athree-year period. In fiscal year 2024, there were 85,595 non-executive options awarded,72,670 of which vested on the first anniversary from the date of grant and 12,925 of which vest monthly over athree-year period.

Share option activity

The number and weighted average exercise prices of share options were as follows:

The weighted average fair value of options granted in 2025 was $16.05 (2024: $37.71;2023: $38.57). The weighted average share price at the date of exercise of the options during the year was $33.47 (2024: $63.70;2023: $56.73).

In the years ended December 31, 2025,2024 and 2023, the total intrinsic value of stock options exercised was $8.8 million, $14.4 million and $58.4 million, respectively. The tax benefit arising on the exercise of stock optionswas $0.8 million, $2.2 million and $3.1 million for the years ended December 31, 2025,2024 and 2023, respectively.

As of December 31, 2025, total unrecognized compensation expense related to share options granted but not vested was$18.7 million, which the Company expects to recognize over a remaining weighted-average period of 1.5 years.

Awards granted in the year ended December 31, 2025,2024 and 2023, have been valued using the Black-Scholes option pricing model. The assumptions used in the models for share options granted during the years ended December 31, 2025,2024 and 2023, were as follows:

Restricted share unit activity

In February 2025, the Company granted RSU awards that vest over afour-year service period with 25% on each anniversary of the grant date. An RSU award represents the right to receiveone of the Company’s ADSs upon vesting of the RSU. The fair value of each RSU award is based on the closing price of the Company’s ADSs on Nasdaq on the date of grant.

The number and weighted average fair value of RSUs were as follows:

As of December 31, 2025, total unrecognized compensation expense related to RSUs granted but not vested was$7.4 million, which the Company expects to recognize over a remaining weighted-average period of 2.1 years.

11. Basic and diluted net loss per share

Basic and diluted net loss per share is calculated as follows (in thousands, except share and per share amounts):

A total of 10,870,472,9,422,875 and 8,967,882 shares issuable upon the exercise of outstanding share options and vesting of RSUsfor the years ended December 31, 2025,2024 and 2023, respectively, have been excluded from the calculation of diluted net loss per share due to their anti-dilutive effect.

For theyear ended December 31, 2025, shares issuable upon the potential conversion of all of the Notes (as defined in Note 7. “Non-current interest-bearing loans and borrowings”) were excluded from the calculation of diluted net loss per sharedue to their anti-dilutive effect.

12. Income taxes

Net loss before income taxes is as follows (in thousands):

The components of income tax (expense) benefit are as follows (in thousands):

The tax effects of temporary differences and carryforwards that give rise to deferred tax assets and liabilities were as follows (in thousands):

The movements in the deferred tax asset valuation allowances are as follows (in thousands):

Reconciliation of the U.K. statutory income tax rate, the income tax rate of the country of domicile of the Company, to the Company’s effective income tax rate is as follows (in percentages):

State taxes in Tennessee and Kentucky for the years ended December 31, 2025 and 2024, and Kentucky for the year ended December 31, 2023, represented more than 50 percent of the total tax effect within the United States jurisdiction category.

Income taxes paid (net of refunds) are disaggregated by jurisdiction as follows (in thousands):

Income taxes paid (net of refunds) exceeded 5 percent of total income taxes paid (net of refunds) in the following jurisdictions:

As of December 31, 2025, the Company’s net operating loss carryforwards in the United Kingdom totaled $525.5 million and net operating loss carryforwards in the United States totaled $73.6 million.

As of December 31, 2025, the Company has U.S. R&D credit carryforwards totaling $10.3 million, of which, $9.5 million relates to federal tax credits.

U.K. tax credit carryforwards can be carried forward indefinitely to be offset against future tax liabilities of the company. Non-U.K. net operating loss carryforwards can be carried forward indefinitely. U.S. tax credit carryforwards can be carried forward for 20 years to be offset against future tax liabilities, subject to a minimum tax payment of 25% of the tax charge.

A valuation allowance is established when it is more likely than not that some portion or all of a deferred tax asset will not be realized. The realization of deferred tax assets depends on the generation of future taxable income during the period in which related temporary differences become deductible. The majority of the Company’s deferred tax assets relate to net operating loss and R&D carryforwards that can only be realized if the Company is profitable in future periods. Accordingly, the Company has provided a valuation allowance against a substantial amount of the net deferred tax assets due to uncertainties as to their ultimate realization.

The Company operates in multiple jurisdictions with complex tax and regulatory environment and the Company's tax returns are periodically audited or subjected to review by tax authorities. The following table summarizes tax years that remain subject to examination by tax jurisdiction as of December 31, 2025:

The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. As of December 31, 2025 and 2024, the Company hasnot recorded any provision for uncertain tax positions.

13. Segment information

The Company operates inone operating segment: immunotherapies, which is focused on pioneering and delivering transformative immunomodulating medicines in the areas of cancer, infectious diseases and autoimmune diseases. The Company primarily generates revenue fromone stream, revenue from the sale of therapies, which consists of sales of KIMMTRAK. Historically, the Company had a second stream, collaboration revenue, which is no longer significant. The Company manages its business activities on a consolidated basis. Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker ("CODM"), the Chief Executive Officer, in making decisions regarding resource allocation and assessing performance. The CODM evaluates financial performance, monitors budget versus actual results and allocates resources using financial information reported on a company-wide basis and therefore the measure of segment profit or loss used is consolidated net loss. The measure of segment assets is reported on the consolidated balance sheet as total assets. The accounting policies of the immunotherapies segment are the same as those described in Note 2. "Summary of significant accounting policies". The following table summarizes the reportable segment's financial information (in thousands):

(a) Other segment expenses, net includes other internal R&D expenses, share-based compensation expense, R&D tax credits, interest income, interest expense, foreign currency (loss) gain, other income (expense), net and income tax benefit (expense).

Other information

The total of non-current assets other than deferred tax assets located in the United Kingdom as of December 31, 2025 is $62.1 million (2024: $55.9 million). The total located in the United States is $8.4 million (2024: $8.8 million).

14. Commitments and contingencies

Lease commitments

See “Leases” for the maturities of operating lease liabilities as of December 31, 2025.

Manufacturing commitments

The Company enters into a number of manufacturing commitments for the future purchase of materials and contract manufacturing services. While the majority of such contracts can be cancelled on reasonable notice, due to the significant ongoing expenditure associated with the Company’s programs, including brenetafusp, the Company estimates it has noncancellable commitments in relation to the development and supply of product candidates totaling, $19.0 million, the majority of which are estimated to be paid within twelve months from the balance sheet date.

Gates collaboration

Under the terms of the Company’s agreement with the Gates Foundation, the Company is required to develop, manufacture and commercialize soluble TCR bispecific therapeutic candidates targeted to mutually agreed neglected diseases, currently HIV, with the potential to treat people at an affordable price in developing countries. In the event of certain defaults by the Company under the agreement, which the Company considers to be within its control, the Gates Foundation has the right to sell, or require the Company to buy back, any of the shareholdings in the Company held by the Gates Foundation. In such an event, if within 12 months after such redemption or sale, the Company experiences a change in control at a valuation of more than 150% of the valuation used for the redemption or the sale of the shares, the Company has agreed to pay the Gates Foundation compensation equal to the excess of what it would have received in such transaction if it still held its shares at the time of such change of control over what it received in the sale or redemption of its shares.

Legal proceedings

The Company is not currently a party to any material legal proceedings.