Condensed Consolidated Balance Sheets (Unaudited) (In CHF thousands) As of March 31, December 31, Note 2025 2024 Assets Non-current assets Property, plant and equipment 5 2,761 2,651 Right-of-use assets 6 5,186 5,437 Int

Condensed Consolidated Balance Sheets (Unaudited)

The accompanying notes are an integral part of these Interim Condensed Consolidated Financial Statements (Unaudited).

Condensed Consolidated Statements of Income/(Loss) (Unaudited)

(In CHF thousands, except for per-share data)

Condensed Consolidated Statements of Comprehensive Income/(Loss) (Unaudited)

The accompanying notes are an integral part of these Interim Condensed Consolidated Financial Statements (Unaudited).

Condensed Consolidated Statements of Changes in Equity (Unaudited)

The accompanying notes are an integral part of these Interim Condensed Consolidated Financial Statements (Unaudited).

Condensed Consolidated Statements of Cash Flows (Unaudited)

The accompanying notes are an integral part of these Interim Condensed Consolidated Financial Statements (Unaudited).

Notes to the Interim Condensed Consolidated Financial Statements (Unaudited)

(In CHF thousands, except share and per share amounts)

AC Immune SA was founded in 2003. The Company controls a fully-owned subsidiary, AC Immune USA, Inc. ("AC Immune USA" or "Subsidiary" and, together with AC Immune SA, "AC Immune," "ACIU," "Company," "we," "our," "ours," "us"), which was organized under the laws of Delaware, USA in June 2021. The Company and its Subsidiary form the Group.

AC Immune SA is a clinical-stage biopharmaceutical company leveraging our two proprietary technology platforms to discover, design and develop novel proprietary medicines and diagnostics for prevention and treatment of neurodegenerative diseases (NDD) associated with protein misfolding. Misfolded proteins are generally recognized as the leading cause of NDD, such as Alzheimer's disease (AD) and Parkinson's disease (PD), with common mechanisms and drug targets, such as amyloid beta (Abeta), Tau, alpha-synuclein (a-syn) and TDP-43. Our corporate strategy is founded upon a three-pillar approach that targets (i) AD, (ii) focused non-AD NDD including Parkinson's disease, ALS and NeuroOrphan indications and (iii) diagnostics. We use our two unique proprietary platform technologies, SupraAntigen (conformation-specific biologics) and Morphomer (conformation-specific small molecules), to discover, design and develop novel medicines and diagnostics to target misfolded proteins.

The Interim Condensed Consolidated Financial Statements of AC Immune SA as of and for the three months ended March 31, 2025 were authorized for issuance by the Company's Audit and Finance Committee on April 29, 2025.

Statement of compliance

These Interim Condensed Consolidated Financial Statements as of March 31, 2025 and for the three months ended March 31, 2025 and 2024, have been prepared in accordance with International Accounting Standard 34 (IAS 34), Interim Financial Reporting, as issued by the International Accounting Standards Board (IASB), and such financial information should be read in conjunction with the audited consolidated financial statements in AC Immune's Annual Report on Form 20-F for the year ended December 31, 2024.

Basis of measurement

These Interim Condensed Consolidated Financial Statements have been prepared under the historical cost convention except for items that are required to be accounted for at fair value.

Functional and reporting currency

These Interim Condensed Consolidated Financial Statements and accompanying notes are presented in Swiss Francs (CHF), which is AC Immune SA's functional currency and the Group's reporting currency. The Company's subsidiary has a functional currency of the U.S. Dollar (USD). The following exchange rates have been used for the translation of the financial statements of AC Immune USA:

Critical judgments and accounting estimates

The preparation of the Company's Interim Condensed Consolidated Financial Statements in conformity with IAS 34 requires management to make judgments, estimates and assumptions that affect the amounts reported in the Interim Condensed Consolidated Financial Statements and accompanying notes, and the related application of accounting policies as it relates to the reported amounts of assets, liabilities, income and expenses.

The areas where AC Immune has had to make judgments, estimates and assumptions relate to (i) revenue recognition on Option, Licensing and Collaboration Agreements (OLCAs), (ii) clinical development accruals, (iii) net employee defined benefit liability, (iv) share-based compensation, (v) right-of-use assets and lease liabilities and (vi) our IPR&D asset (intangible asset). Actual results may differ from these estimates. Estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future periods affected.

Fair value of financial assets and liabilities

The Company's financial assets and liabilities are composed of receivables, short-term financial assets, cash and cash equivalents, trade payables and lease liabilities. The fair value of these financial instruments approximates their respective carrying values due to the short-term maturity of these instruments, and are held at their amortized cost in accordance with IFRS 9, unless otherwise explicitly noted.

Accounting policies, new standards, interpretations and amendments adopted by the Company

The accounting policies adopted in the preparation of the Interim Condensed Consolidated Financial Statements are consistent with those followed in the preparation of the Company's annual consolidated financial statements for the year ended December 31, 2024.

There are no new IFRS standards, amendments or interpretations that are mandatory as of January 1, 2025 that are relevant to the Company.

New standards that are not yet effective

In April 2024, the IASB issued IFRS 18 Presentation and Disclosure in Financial Statements (IFRS 18). The new standard on presentation and disclosure in the financial statements will change the structure of the statement of profit or loss, require disclosures for certain profit or loss performance measure that are reported outside of the financial statements, and will enhance principles on aggregation and disaggregation within the notes to the financial statements. It also establishes a new starting point and revised requirements for interest and dividends in the statement of cash flows. This new standard will be effective for annual and interim reporting periods beginning on January 1, 2027 and will require retrospective application. The Company is currently evaluating the new standard to determine how it will impact the presentation and disclosure in its financial statements.

The Company believes that it will be able to meet all of its obligations as they fall due for at least 12 months from the filing date of this Form 6-K, after considering the Company's cash position of CHF 20.0 million and short-term financial assets of CHF 125.7 million as of March 31, 2025. Hence, these unaudited Interim Condensed Consolidated Financial Statements have been prepared on a going-concern basis.

To date, the Company has financed its cash requirements primarily from its public offerings, share issuances, contract revenues from its OLCAs and grants. The Company is a clinical stage company and is exposed to all the risks inherent to establishing a business. Inherent to the Company's business are various risks and uncertainties, including the substantial uncertainty as to whether current projects will succeed and our ability to raise additional capital as needed. These risks may require us to take certain measures such as delaying, reducing or eliminating certain programs. The Company's success may depend in part upon its ability to (i) establish and maintain a strong patent position and

protection, (ii) enter into collaborations with partners in the pharmaceutical and biopharmaceutical industries, (iii) successfully move its product candidates through clinical development, (iv) attract and retain key personnel and (v) acquire capital to support its operations.

3.Contract revenue and other operating income

For the three months ended March 31, 2025 and 2024, AC Immune generated CHF 1.0 million in contract revenues, compared to no contract revenues in the prior comparable period.

3.1Option, licensing and collaboration agreements

For a discussion of our OLCAs for the fiscal year ended December 31, 2024, please refer to Note 13.1 "Licensing and Collaboration agreements" of our Annual Report on Form 20-F for the year ended December 31, 2024 filed on March 13, 2025.

Anti-Abeta Active Immunotherapy in AD - 2024 agreement with Takeda Pharmaceuticals, USA, Inc.

In May 2024, the Company entered into a worldwide option and license agreement with Takeda Pharmaceuticals, USA, Inc. (Takeda) for our active immunotherapies targeting Abeta, including ACI-24.060 for the treatment of AD. AC Immune will be responsible for completing the ABATE trial. Following option exercise, Takeda would conduct and fund all further clinical development and be responsible for all global regulatory activities as well as worldwide commercialization. Under the terms of the agreement, AC Immune received an upfront payment of USD 100.0 (CHF 92.3) million in May 2024 and is eligible to receive an option exercise fee in the low-to-mid nine-figure USD range and additional potential development, commercial and sales-based milestones of up to approximately USD 2.1 (CHF 1.9) billion if all related milestones are achieved over the course of the agreement. Upon commercialization, AC Immune will be entitled to receive tiered mid-to-high teens percentages royalties on worldwide net sales.

Under the terms of the agreement, Takeda may terminate the agreement at any time by providing 90 days' notice to the Company. If not otherwise terminated, the agreement shall continue until Takeda decides not to exercise its license option or until the expiration of all royalty obligations as outlined in the contract.

AC Immune assessed this arrangement in accordance with IFRS 15 and concluded that Takeda is a customer. The Company identified the following performance obligations under the contract: (i) a license option and (ii) development, chemistry, manufacturing, and controls ("CMC") and regulatory activities as outlined in the development and CMC plans, which are necessary to deliver the data package to Takeda. AC Immune concluded that the license option is considered a material right, as the value of the license exceeds the option exercise fee, thereby considering it a distinct performance obligation. The development, CMC, and regulatory activities are treated as one distinct performance obligation because the underlying activities are not distinguishable in the context of the contract and are inputs to an integrated development program that will generate valuable data and information for Takeda in determining whether to exercise the option.

At the agreement's execution, the transaction price included only the upfront and non-refundable consideration of USD 100.0 (CHF 92.3) million. At inception, none of the development milestones, which may occur prior to the Takeda option exercise, were included in the transaction price, as all milestone amounts were fully constrained. The Takeda option exercise payment and any future development and commercial milestone payments, and royalties following the Takeda option exercise were excluded from the initial transaction price at contract inception. The option exercise fee is considered variable consideration as it depends on Takeda's decision to exercise. In assessing that future development or commercial milestones are fully constrained, the Company considered numerous factors, including that the receipt of

these milestones is contingent upon success in future clinical trials and the licensee's efforts, and thus not highly probable to obtain. Any consideration related to sales-based milestones (including royalties) will be recognized when the related sales occur, as they predominantly relate to the license that will be granted to Takeda upon exercise and therefore have also been excluded from the transaction price. The Company will re-evaluate the transaction price in each reporting period as uncertain events are resolved or other changes in circumstances occur.

The valuation of each performance obligation involves estimates and assumptions, with the timing of revenue recognition determined by either delivery or the provision of services. In line with the allocation objective under IFRS 15, the Company allocated the USD 100.0 (CHF 92.3) million upfront payment within the transaction price to the license option and development, CMC, and regulatory activities, using the relative stand-alone selling price method. For the standalone selling price of the license option, the Company utilized an income-based approach, which included key assumptions such as the post-option development timeline and costs, revenue forecasts, discount rates, and probabilities of development and regulatory success. The standalone selling price for the development, CMC and regulatory activities was calculated using a cost-plus margin approach based on the estimated development timeline. The Company allocated the transaction price based on the relative standalone selling prices, assigning USD 87.4 (CHF 80.7) million to the license option and USD 12.6 (CHF 11.6) million to development, CMC, and regulatory activities.

The Company has deferred revenue recognition for the license option and will recognize the entirety of the revenue either when the option is exercised and Takeda obtains the exclusive license, or when the option expires. The Company will recognize revenue related to the development, CMC and regulatory performance obligation over the estimated period of completion of these obligations, using an input method reflecting the costs incurred relative to the total costs expected to be incurred.

For the three months ended March 31, 2025, the Company recorded contract revenue CHF 1.0 million reflecting its efforts under this agreement for the development, CMC, and regulatory activities of our active immunotherapies targeting Abeta, compared to no contract revenue in the prior comparable period.

As of March 31, 2025, the Company recorded CHF 88.6 million in deferred contract revenue related to the unsatisfied performance obligations under this agreement. The deferred contract revenue allocated to the license option is classified as short-term on the condensed consolidated balance sheets because, in accordance with IAS 1, the Company does not have the right to defer the settlement of that portion for at least twelve months after the reporting period. The deferred contract revenue allocated to development, CMC, and regulatory activities will be recognized over the remaining performance period and classified as either current or non-current on the condensed consolidated balance sheets, based on the expected timing of satisfaction of the performance obligations.

In periods for which we have a loss, basic net loss per share is the same as diluted net loss per share. We have excluded from our calculation of diluted loss per share all potentially dilutive in-the-money share options. See "Note 12. Share-based compensation" for the potentially dilutive equity awards.

5.Property, plant and equipment

The following table shows the movement in the net book values of property, plant and equipment for the three months ended March 31, 2025:

6.Right-of-use assets, long-term financial assets and lease liabilities

AC Immune recognized no additions for its right-of-use of leased assets for the three months ended March 31, 2025.

Regarding lease liabilities, the amortization depends on the rate implicit in the contract or the incremental borrowing rate for the respective lease component. The weighted averages of the incremental borrowing rates are 3.5% for buildings, 3.3% for office equipment and 7.2% for IT equipment, respectively.

The following table shows the movements in the net book values of right-of-use of leased assets for the three months ended March 31, 2025:

There are no variable lease payments that are not included in the measurement of lease obligations. All extension options have been included in the measurement of lease obligations.

For the three months ended March 31, 2025, and 2024, the impact on the Company's condensed consolidated statements of income/(loss) and the condensed consolidated statements of cash flows is as follows:

The following table presents the contractual undiscounted cash flows for lease obligations as of March 31, 2025:

The Company also has deposits in escrow accounts totaling CHF 0.6 million and CHF 0.4 million for leases of the Company's premises as of March 31, 2025 and December 31, 2024, respectively. These deposits are presented in Long-term financial assets on the Company's condensed consolidated balance sheets.

Accrued expenses consists of accrued R&D costs, accrued payroll expenses and other accrued expenses totaling CHF 11.1 million and CHF 12.1 million as of March 31, 2025 and December 31, 2024, respectively.

AC Immune's acquired IPR&D asset is a clinically-validated active vaccine candidate for the treatment of Parkinson's disease. The asset is not yet ready for use until the asset obtains market approval and is therefore not currently being amortized. The carrying amount and net book value are detailed below:

In accordance with IAS 36 Impairment of Assets, the IPR&D asset is reviewed at least annually for impairment by assessing the fair value less costs to sell (recoverable amount) and comparing this to the carrying value of the asset. The valuation is considered to be Level 3 in the fair value hierarchy in accordance with IFRS 13 Fair Value Measurement due to unobservable inputs used in the valuation. The Company has determined the IPR&D asset not to be impaired as of

December 31, 2024. As of March 31, 2025, the Company did not identify any triggering events that could result in an impairment of the IPR&D asset.

Prepaid expenses include prepaid R&D costs, administrative costs, and employee social obligations totaling CHF 3.6 million and CHF 4.3 million as of March 31, 2025 and December 31, 2024, respectively.

10.Cash and cash equivalents and short-term financial assets

The following table summarizes AC Immune's cash and cash equivalents and short-term financial assets as of March 31, 2025 and December 31, 2024:

For the three months ended March 31, 2025, the net proceeds from the maturity of investments in short-term financial assets amounted to CHF 3.6 million, compared to net investments of CHF 23.3 million in the prior comparable period.

For a discussion of our at the market offering program with Jefferies LLC for the fiscal year ended December 31, 2024, please refer to Note 11 "Share capital" of our Annual Report on Form 20-F for the year ended December 31, 2024 filed on March 13, 2025.

As of March 31, 2025 and December 31, 2024, the Company had 10,899,773 treasury shares remaining, respectively.

12.Share-based compensation

Share-based option awards

As of March 31, 2025, there are equity-based instruments outstanding that the Company has granted under two different plans.

The Company's 2016 Share Option and Incentive Plan (SOIP) was approved by the shareholders at the ordinary shareholders' meeting in November 2016. The 2016 Plan authorizes the grant of incentive and non-qualified share options, share appreciation rights, restricted share awards, restricted share units, unrestricted share awards, performance share awards, performance-based awards to covered employees and dividend equivalent rights. The Company only grants equity-based instruments from the SOIP as of March 31, 2025.

The number and weighted-average exercise prices (in CHF) of options under the share option programs for Plans C1 and the 2016 SOIP are as follows:

Restricted share awards

A summary of share awards (restricted share and restricted share units) activity as of March 31, 2025 and changes during three months ended is presented below:

The expense charged against the income statement was CHF 1.6 million and CHF 1.9 million for the three months ended March 31, 2025 and 2024, respectively. The expense is determined by the Company based on the number of instruments that are expected to become exercisable.

13.Finance result, net

For the three months ended March 31, 2025 and 2024, AC Immune recorded CHF 0.3 million and CHF 2.2 million in net financial gains, respectively. The decrease is primarily related to unfavorable foreign currency exchange

differences related to movement in the CHF versus foreign currencies, predominantly the U.S. Dollar, compared with the preceding year end rate.

14.Subsequent events