Silence Therapeutics plc

(Unaudited)

1. General information

1.1. Nature of the business

Silence Therapeutics plc and its subsidiaries, or together, the Group, are primarily involved in the discovery, delivery and development of RNA therapeutics. Silence Therapeutics plc, a public company limited by shares registered in England and Wales, with company number 02992058, is the Group’s ultimate parent company. The Company’s registered office is 27 Eastcastle Street, London, United Kingdom W1W 8DH and the principal place of business is 72 Hammersmith Road, London, United Kingdom W14 8TH.

2. Summary of significant accounting policies

2.1. Basis of preparation

The accompanying unaudited condensed consolidated interim financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP, for interim financial reporting and pursuant to the requirements for reporting on Form 10-Q and Article 10 of Regulation S-X. Accordingly, certain information and disclosures required by U.S. GAAP for complete consolidated financial statements are not included herein. These interim statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024 filed with the Securities and Exchange Commission, or the SEC, on February 27, 2025. In the opinion of management, all adjustments considered necessary for a fair statement of these interim statements have been included and are of a normal and recurring nature. The results for the three and six months ended June 30, 2025 are not necessarily indicative of the results to be expected for the year ending December 31, 2025, any other interim periods, or any future year or period.

The Group previously prepared its consolidated financial statements in accordance with International Financial Reporting Standards as issued by the International Accounting Standards Board when the Group qualified as a foreign private issuer under the rules and regulations of the SEC. In connection with the loss of the Group’s status as a foreign private issuer, the Group is required to report with the SEC on domestic forms and comply with domestic company rules in the United States, including preparation of its financial statements in accordance with U.S. GAAP. The transition to U.S. GAAP was made retrospectively for all periods from the Group’s inception.

2.2. Functional and reporting currency

The reporting currency of the condensed consolidated financial statements is U.S. Dollars, or USD or $. The functional currency of the Group’s subsidiaries reflects the economic environment of their respective operations. All amounts disclosed have been rounded to the nearest thousand, unless otherwise stated.

Due to the loss of the Group’s status as a foreign private issuer, effective January 1, 2025, the Group was required as a domestic filer to change its reporting currency of the condensed consolidated financial statements from British pound sterling, or GBP, to USD. The change in reporting currency was applied retrospectively. Condensed consolidated financial statements for all periods have been recast into USD and presented to the nearest thousand dollars.

2.3. Principles of consolidation

The condensed consolidated financial information comprises the financial statements of Silence Therapeutics plc and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated on consolidation.

2.4. Use of estimates

The preparation of the condensed 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, the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions reflected in the Group’s condensed consolidated financial statements include, but are not limited to, the recognition of revenue and research and development expenses. The Group bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates when there are changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ materially from those estimates.

2.5. Going concern

The Group has incurred recurring losses since inception, including net losses of $55.9 million for the six months ended June 30, 2025. As of June 30, 2025, the Group had accumulated losses of $529.8 million and cash outflows from operating activities for the six months ended June 30, 2025 was $34.1 million.

The Group expects to incur operating losses for the foreseeable future as it continues its research and development efforts, seeks to obtain regulatory approval of its product candidates and pursues any future product candidates the Group may develop.

To date, the Group has funded its operations through upfront payments and milestones from collaboration agreements, equity offerings and proceeds from private placements, as well as management of expenses and other financing options to support its continued operations. In 2024, the Group raised additional proceeds of $27.7 million before deducting $0.9 million in placement agent fees and other expenses, from sales of American Depositary Shares, or ADSs, under its Open Market Sale Agreement with Jefferies LLC, dated October 15, 2021, or the Sales Agreement,. On February 5, 2024, the Group announced a private placement of 5,714,286 of the ADSs, each representing three ordinary shares, at a price of $21.00 per ADS, with new and existing institutional and accredited investors, or the Private Placement. The aggregate gross proceeds of the Private Placement were $120.0 million before deducting approximately $7.7 million in placement agent fees and other expenses. In 2024, the Group received a $10.0 million milestone payment from the AstraZeneca collaboration and received another $2.0 million in milestone payments from the Hansoh collaboration. As of June 30, 2025, the Group had cash and cash equivalents and short-term investments of $114.2 million.

The Group believes that its current cash and cash equivalents are sufficient to fund its operating expenses for at least the next twelve months from the issuance date of these condensed consolidated financial statements. For this reason, the Group continues to adopt the going concern basis in preparing the financial statements.

The Group will need to raise additional funding to fund its operation expenses and capital expenditure requirements in relation to its clinical development activities. The Group may seek additional funding through public or private financings, debt financing or collaboration agreements. Specifically, the Group may receive future milestone payments from existing collaboration agreements which will extend the ability to fund operations. However, these future milestone payments are dependent on achievement of certain development or regulatory objectives that may not occur. The inability to obtain future funding could impact; the Group’s financial condition and ability to pursue its business strategies, including being required to delay, reduce or eliminate some of its research and development programs, or being unable to continue operations or unable to continue as a going concern.

2.6. Recently Issued Accounting Pronouncements

Recently adopted accounting standards

There were no accounting standards adopted in the current period.

Accounting standards issued but not yet adopted

In December 2023, the Financial Accounting Standards Board, or FASB, issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which provides for improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information. This guidance is effective for annual periods beginning after December 15, 2024, and should be applied on a prospective basis with the option to apply the standard retrospectively. Early adoption is permitted. This standard will have no impact on the Group’s consolidated financial statements. The Company is currently evaluating the impact to its income tax disclosures.

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40). Additionally, in January 2025, the FASB issued ASU 2025-01 to clarity the effective date of ASU 2024-03. The amendments in this update require disclosure, in the notes to financial statements, of specified information about certain costs and expenses at each interim and annual reporting period. The amendments are effective for annual periods beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027, with early adoption permitted. This guidance should be applied either prospectively to financial statements issued for reporting periods after the effective date or retrospectively to any or all prior periods presented in the financial statements. The Group is currently evaluating the impact of this guidance on its related disclosures.

3. Revenue

Revenue from collaboration agreements for the three and six months ended June 30, 2025, predominately related to the research collaboration agreement the Group entered into with AstraZeneca in March 2020.

Revenue for the three months ended June 30, 2025 was reflectiveof $0.2 million oftotal revenue from contracts with customers (three months ended June 30, 2024: $0.8 million). There wasno royalty income for the three months ended June 30, 2025 or 2024.

Revenue for the six months ended June 30, 2025 was reflective of $0.4 million of total revenue from contracts with customers (six months ended June 30, 2024: $16.5 million) andno royalty income (six months ended June 30, 2024: $0.1 million). Disaggregation of revenue from contracts with customers is as follows:

Under its collaboration agreement with AstraZeneca, the Group received an upfront cash payment of $20 million in 2020 with a further payment of $40 million received in May 2021. The Group is also eligible to receive specified development and commercial milestone payments as well as tiered royalties on net sales, if any. The Group recognizes the upfront payment and milestone payments over time, in accordance with ASC 606. During the six months ended June 30, 2025, the Group achievedno milestone payments from the collaboration agreement with AstraZeneca (six months ended June 30, 2024: $10.0 million). During the six months ended June 30, 2025, the Group recognized a total of $0.4 million in revenue under its collaboration agreement with AstraZeneca (six months ended June 30, 2024: $15.0 million).

4. Segment reporting

The chief operating decision maker, or CODM, reviews consolidated net loss for the period when assessing the Group’s performance, allocating resources and establishing management’s compensation. In addition to consolidated net loss, the CODM receives discrete information for revenue by major customer and geographic location. Consolidated net loss is used to monitor budget versus actual results and is reviewed against the Group’s peers and competitors as benchmarking. The Group operates asone reportable segment in the specific technology field of RNA therapeutics.

The accounting policies of its operating segment are the same as those described in the Group’s summary of significant accounting policies.

The Group derives revenues from customers through royalty income and research collaboration agreements, each representing a major customer, specifically related to the development of RNAi-based medicines. Refer to Note 3 – Revenue for a further description of the types of products from which the Group derives its revenues.

The measure of segment assets is reported on the balance sheet as total consolidated assets.

The table below provides segment information about the Group:

(a)

Contracted development costs primarily consist of costs incurred under agreements with contract research

organizations and investigative sites that conduct its preclinical studies and clinical trials; costs related to manufacturing active pharmaceutical ingredients and drug products for its preclinical studies and clinical trials; and costs for materials used for in-house research and development activities.

(b)

Personnel R&D costs primarily consist of salaries and personnel-related costs for personnel performing R&D activities or managing those activities that have been out-sourced; and consultants’ costs associated with target selection, preclinical and clinical research activities, and the progression of programs towards clinical trials.

(c)

Other R&D costs include associated facility costs, equipment and other overheads that are directly attributable to R&D and depreciation of capital assets used for research and development activities.

(d)

The other segment items include foreign currency gain/(loss), net, benefit from R&D credit, and other income, net inclusive of bank interest receivable and accretion on U.S. treasury bills.

An analysis of the group’s assets and revenues by location is shown below: