Silence Therapeutics plc: Form 10-Q for the period ended Mar 31, 2026

You should read the following discussion and analysis of our financial condition and results of operations together with our condensed consolidated financial statements, the related notes thereto appearing elsewhere in this Quarterly Report. The following discussion is based on our financial information prepared in accordance with accounting principles generally accepted in the U.S., or U.S. GAAP, as found in the Accounting Standards Codification and Accounting Standards Update of the Financial Accounting Standards Board and the rules and regulations of the SEC. Some of the information contained in this discussion and analysis or set forth elsewhere in this Quarterly Report, including information with respect to our plans and strategy for our business, includes forward-looking statements that involve risks and uncertainties. Our actual results, performance or experience could differ materially from what is indicated by any forward-looking statement due to various important factors, risks and uncertainties, including, but not limited to, those set forth under “Risk Factors” included elsewhere in this Quarterly Report on Form 10-Q.

Overview

We are a biotechnology company focused on discovering and developing novel molecules incorporating short interfering ribonucleic acid, or siRNA, to inhibit the expression of specific target genes thought to play a role in the pathology of diseases with significant unmet medical need. Our siRNA molecules are designed to harness the body’s natural mechanism of RNAi by specifically binding to and degrading messenger RNA, or mRNA, molecules that encode specific targeted disease-associated proteins in a cell. By degrading the message that encodes the disease-associated protein, the production of that protein is reduced and its level of activity is lowered. In the field of RNAi therapeutics, this reduction of disease-associated protein production and activity is referred to as “gene silencing.” Our proprietary mRNAi GOLD™ (GalNAc Oligonucleotide Discovery) platform consists of siRNA product candidates designed to precisely target and ‘silence’ specific disease-associated genes in the liver. Using our mRNAi GOLD platform, we have generated siRNA product candidates targeting areas of high unmet need across rare and common diseases where treatments are limited or inadequate.

Rare Diseases

Divesiran (SLN124) is our potential first-in-class siRNA in Phase 2 development for polycythemia vera, or PV. PV is a rare myeloproliferative neoplasm characterized by the overproduction of red blood cells, or RBCs. Elevated hematocrit, or HCT, - an index of RBC mass - is a hallmark of the disease and HCT levels above 45% increase the risk of thrombotic and cardiovascular events. The current standard of care in all PV patients to control HCT is phlebotomy, daily low-dose aspirin therapy, sometimes in combination with cytoreductive therapies. PV patients have low levels of hepcidin the body’s master regulator of iron. Divesiran works by "silencing" the TMPRSS6 gene, lifting the natural brake on hepcidin - the body's master iron regulator. When TMPRSS6 is turned down in people living with PV, hepcidin levels rise, reducing iron availability to the bone marrow. With less iron available, the overproduction of RBCs seen in PV is reduced. This helps keep HCT levels in a safer range and can reduce or eliminate the need for phlebotomies. Additionally, siRNA therapies have a highly potent and durable effect - enabling less frequent and more convenient dosing. In the Phase 1 part of the SANRECO clinical trial evaluating divesiran treatment in 21 PV patients, divesiran produced durable HCT control and substantially reduced phlebotomy use following infrequent dosing (Q6W). Based on the strong durability observed in Phase 1, the ongoing Phase 2 part of the SANRECO trial is evaluating both a Q6W and Q12W dosing interval. The SANRECO Phase 2 trial is fully enrolled and topline results are anticipated in August 2026. The U.S. Food and Drug Administration, or FDA, has granted divesiran Fast Track and orphan drug designations for PV. Divesiran has also been granted orphan drug designation by the European Commission for PV in Europe. While our initial focus is on PV, divesiran has shown the potential in preclinical studies to address multiple hematological conditions through the unifying mechanism of elevating hepcidin in conditions with dysregulation of iron homeostasis.

SLN548 is our Phase 1 ready siRNA product candidate that works by "silencing" the complement factor B, or CFB, gene, potentially playing a therapeutic role in conditions associated with over activation of this pathway, including complement-mediated renal diseases, among others. SLN548 has demonstrated positive preclinical results and we are seeking a third-party partner to initiate clinical development.

Cardiometabolic Diseases

Zerlasiran (SLN360) is our Phase 3 ready siRNA product candidate for cardiovascular disease that works by "silencing" the LPA gene, lowering production of apolipoprotein(a), a key component of lipoprotein(a), or Lp(a), that has been associated with an increased risk of cardiovascular events. High Lp(a), defined as 125nmol/L or higher, is a genetically determined cardiovascular risk factor affecting at least 20% of the world’s population and is associated with a high risk of heart attack, stroke and aortic stenosis. Unlike low-density lipoprotein, or LDL, Lp(a) levels are predominantly genetically determined, typically by age five, and unaffected by diet or lifestyle. There are currently no approved medicines that selectively lower Lp(a). Guidelines from the European Atherosclerosis Society, or EAS, Canadian Cardiovascular Society, or CCS, and the National Lipid Association, or NLA, suggest at least one test in an adult lifetime. The American College of Cardiology, or ACC, and American Heart Association, or AHA, recommend testing for those with a family history of premature atherosclerotic cardiovascular disease, or ASCVD, or personal history of ASCVD. In Phase 1 and Phase 2 clinical trials, zerlasiran showed the potential to substantially lower Lp(a) levels in ASCVD patients with persisting effects following infrequent dosing and was well tolerated with no major safety concerns. We have received positive regulatory feedback from the FDA and European Medicines Agency, or EMA, on the Phase 3 cardiovascular outcomes study design for zerlasiran in patients with high Lp(a). In 2025, we completed core Phase 3 readiness activities, including manufacturing and supply scale up. Zerlasiran is Phase 3 ready and we are seeking a third-party partner for potential Phase 3 development as well as potential future commercialization.

SLN312 is our siRNA product candidate under our collaboration with AstraZeneca that works by "silencing" ANGPTL3, an important modulator of lipid metabolism. Inhibition of ANGPTL3 has emerged as a promising new therapeutic approach to reduce triglycerides (TG) and LDL-C levels, the latter independent of the LDL-C receptor (LDLR) function. Since ANGPTL3 suppresses lipoprotein lipase, or LPL, and endothelial lipase, or EL, activity, its inhibition facilitates the clearance of very low-density lipoprotein cholesterol, decreasing both LDL-C and TG levels. AstraZeneca shared interim results from its Phase 1 randomized, single-blind, placebo-controlled trial assessing SLN312 in 98 patients with dyslipidemia. Interim results showed SLN312 produced durable dose-dependent reductions in ANGPTL3, triglycerides and atherogenic lipoproteins after single and multiple doses. The strong duration of effect observed supports potential for infrequent dosing. SLN312 was well tolerated with no safety concerns identified. Phase 1 data presentations are planned for medical and research congresses in 2026. On March 4, 2026, AstraZeneca notified Silence that they will not pursue further development of SLN312 beyond Phase 1. We will re-gain full development, manufacturing and commercialization rights globally to this clinical asset following Phase 1 and are evaluating plans for further clinical development.

SLN365 is our potential first-in-class siRNA product candidate that works by "silencing" GPR146, a novel mechanism of action for the management of cholesterol levels in patients, independent of LDLR function. Hypercholesterolemia is a highly prevalent indication with an estimated one in 300 individuals worldwide living with the familial form HeFH (heterozygous) and around one in 300,000 individuals suffering from the form HoFH (homozygous) globally. SLN365 has demonstrated promising preclinical results in non-human primates and we anticipate additional preclinical data in the second quarter of 2026.

SLN098 is our siRNA product candidate that works by "silencing" INHBE, a novel target for obesity supported by human genetics, strong preclinical data and emerging third-party clinical data demonstrating early efficacy and safety. Despite recent advances in obesity treatment, limitations of current standards of care leave millions at risk of further complications. Around one billion patients worldwide are affected by obesity and associated co-morbidities. Current obesity treatments offer weight loss around 15-20% which plateaus after 12-24 months and are associated with up to 40% lean muscle mass loss. More than two thirds of weight loss is regained within the first year after discontinuation of treatment. There is also poor tolerability and compliance with up to 30% of patients discontinuing GLP/GIP agonists treatment. SLN098 has the opportunity to address unmet needs including increasing fat loss, preventing muscle mass loss and slowing weight regain. SLN098 has demonstrated deep and durable knockdown in nonhuman primates and we anticipate additional disease model data in the second quarter of 2026 to further validate the mechanism of action. We believe there is an opportunity to develop SLN098 either as a monotherapy or add-on to GLP/GIP agonists or as a weight maintenance treatment.

First Quarter 2026 and Recent Business Developments

Divesiran: First-in-class siRNA for PV

• SANRECO Phase 1 study abstract accepted for poster presentation at the European Hematology Association (EHA) 2026 Annual Congress taking place June 11-14, 2026.
• Divesiran, A Novel GalNac Conjugated SiRNA, Reduces Phlebotomies, Improves Iron Stores and Symptoms in Polycythemia Vera Patients in Sanreco Phase 1 Study

Abstract #PF886, Poster Session 1 on Friday, June 12 (6:45-7:45 p.m. CEST)

• SANRECO Phase 2 double-blind, placebo-controlled trial evaluating divesiran 6 mg (Q6W and Q12W dosing intervals) in 48 phlebotomy-dependent PV patients is ongoing with topline results on-track for the third quarter of 2026.

SLN312 (AZD1705): Phase 1 siRNA with a competitive profile for dyslipidemia

• Phase 1 study abstract accepted for late-breaking oral presentation at the European Atherosclerosis Society (EAS) Congress taking place May 24-27, 2026.
• Liver-Targeted ANGPTL3 Silencing with AZD1705 Lowers Atherogenic Lipoproteins: Preclinical Validation and Phase 1 Results

Abstract #1610, Late Breaker Clinical Abstracts Session on Tuesday, May 26 (3:45–5:15 p.m. EST)

Collaborations

AstraZeneca

In March 2020, we entered into a collaboration agreement with AstraZeneca to discover, develop and commercialize siRNA therapeutics for the treatment of cardiovascular, renal, metabolic and respiratory diseases. Under this agreement, AstraZeneca made an upfront cash payment to us of $20.0 million in May 2020. AstraZeneca made an additional unconditional cash payment to us of $40.0 million which was received in May 2021. In March 2020, an affiliate of AstraZeneca also subscribed for 4,276,580 new ordinary shares for an aggregate subscription price of $20.0 million.

The collaboration covered five targets initially with AstraZeneca opting to extend the collaboration to a further five targets. AstraZeneca agreed to pay us $10.0 million upon the exercise of each option to collaborate on an additional target. For each target selected, we are eligible to receive up to $140.0 million in potential milestone payments upon the achievement of milestones relating to the initiation of specified clinical trials, the acceptance of specified regulatory filings and the first commercial sale in specified jurisdictions. For each target selected, we are also eligible to receive up to $250.0 million in potential commercial milestone payments, upon the achievement of specified annual net sales levels, as well as tiered royalties as a percentage of net sales ranging from the high single digits to the low double digits.

In May 2023, AstraZeneca nominated the first product candidate under our collaboration, SLN312 (ANGPTL3), triggering a $10.0 million option fee to us. In February 2024, AstraZeneca initiated a Phase 1 clinical trial for SLN312 which triggered another $10.0 million milestone payment to us. On March 4, 2026, AstraZeneca notified Silence that they will not pursue further development of SLN312 beyond Phase 1. We will re-gain full development, manufacturing and commercialization rights globally to this clinical asset following Phase 1 and are evaluating plans for further clinical development.

Components of Results of Operations

Revenue

We do not have any approved products. Accordingly, we have not generated any revenue from product sales, and we do not expect to generate any revenue from the sale of any products unless and until we obtain regulatory approvals for, and commercialize any of, our product candidates. In the future, we will seek to generate revenue primarily from product sales and, potentially, regional or global strategic collaborations with third parties.

We recognized the upfront payment, milestone payments, payments for personnel costs and other research funding payments over time.

Under the AstraZeneca collaboration, we received an upfront cash payment of $20.0 million and an additional payment of $40.0 million in May 2021. We are also eligible to receive specified development and commercial milestone payments as well as tiered royalties on net sales, if any. We recognize the upfront payment and milestone payments over time. During the three months ended March 31, 2026, we recognized a total of $0.4 million in revenue under the AstraZeneca collaboration (three months ended March 31, 2025: $0.1 million).

Cost of Sales

Cost of sales consists of research and development expenditure that is directly related to work carried out on revenue generating contracts. This includes salary costs that are apportioned based on time spent by employees working on these contracts as well as costs of materials and costs incurred under agreements with contract research organizations, or CROs.

Operating Expenses

We classify our operating expenses into two categories: research and development costs and general and administrative expenses. Personnel costs, including salaries, benefits, bonuses and share-based payment expenses, comprise a significant component of each of these expense categories. We allocate expenses associated with personnel costs based on the function performed by the respective employees.

Research and Development Costs

The largest component of our total operating expenses since inception has been costs related to our research and development activities, including the preclinical and clinical development of our product candidates. We expense research and development costs as they are incurred and classify them as contracted development, personnel and other.

Our contracted development costs primarily consists of:

• costs incurred under agreements with CROs and investigative sites that conduct our preclinical studies and clinical trials;
• costs related to manufacturing active pharmaceutical ingredients and drug products for our preclinical studies and clinical trials; and
• costs for materials used for in-house research and development activities.

Our personnel research and development expense primarily consists of:

• salaries and personnel-related costs, including bonuses, benefits, recruitment costs and any share-based payment expenses, for our personnel performing research and development 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.

Our other research and development costs primarily consists of:

• costs of related facilities, equipment and other overhead expenses that are considered directly attributable to research and development; and
• depreciation of capital assets used for research and development activities.

The successful development of our product candidates is highly uncertain. Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials. Accordingly, we expect research and development costs to increase significantly for the foreseeable future as programs progress.

The duration, costs and timing of clinical trials and development of our product candidates will depend on a variety of factors, including:

• the scope, rate of progress, results and expenses of our ongoing and future clinical trials, preclinical studies and research and development activities;
• the potential need for additional clinical trials or preclinical studies requested by regulatory authorities;
• potential uncertainties in clinical trial enrollment rates or drop-out or discontinuation rates of patients;
• competition with other drug development companies in, and the related expense of, identifying and enrolling patients in our clinical trials and contracting with third-party manufacturers for the production of the drug product needed for our clinical trials;
• the achievement of milestones requiring payments under in-licensing agreements, if any;
• any significant changes in government regulation;
• the terms and timing of any regulatory approvals; and
• the ability to market, commercialize and achieve market acceptance for any of our product candidates, if they are approved.

General and Administrative Expenses

General and administrative expenses consist of personnel costs, allocated expenses and other expenses for outside professional services, including legal, audit, tax and accounting services, public relations and investor relations services. Personnel costs consist of salaries, bonuses, benefits, recruitment costs and share-based payment expenses for personnel in executive, finance, business development and other support functions. Other administrative expenses include office space-related costs not otherwise allocated to research and development costs, insurance expenses, and costs of our information systems and costs for compliance with the day-to-day requirements of being a public company listed in the United States. We anticipate that our administrative expenses will remain consistent to support our continued research and development and potential commercialization of our product candidates. We also expect to continue incurring additional expenses as a public company in the United States, including expenses related to compliance with the rules and regulations of the SEC and the Nasdaq Stock Market, or Nasdaq, additional insurance expenses, expenses related to investor relations activities and other administrative and professional services.

Foreign Currency Gain (loss), net

Foreign exchange gains and losses primarily relate to cash and short-term investments held in foreign currencies (primarily USD and Euros).

Other Income, net

Other income (expense) primarily relates to interest earned on our cash, cash equivalents, as well as accretion earned on our U.S. treasury bills.

Taxation and Benefit from R&D Tax Credit

We are subject to corporate taxation in the United Kingdom, the United States and Germany. Due to the nature of our business, we have generated losses since inception. Our income tax credit recognized represents the sum of the research and development, or R&D, tax credits recoverable in the United Kingdom.

As a company that carries out extensive research and development, or R&D, activities, we seek to benefit from the U.K. R&D tax credit regime. In respect of accounting periods in which we qualify as a Small and Medium-sized

Enterprise, or SME, and in which our qualifying R&D expenditure represents 30% (for periods from April 1, 2024) or more of the total (meaning we are considered as “R&D-intensive” during such accounting period), we may, under this regime, surrender the trading losses that arise from our R&D activities for a cash rebate of up to 26.97% of qualifying R&D expenditure. Based on our current forecast, we do not expect to meet the qualifying R&D expenditure threshold for the year ended December 31, 2026; however, we plan to still expect to claim at the R&D intensive rate as we expect to meet conditions for a grace period under the U.K. R&D tax credit regime. Accordingly, if we cease to qualify as an R&D-intensive SME, in future, we will either cease to be able to claim cash rebates in respect of our R&D activities, or only be able to receive cash payments or other tax relief (under other provisions of the U.K. R&D tax credit regime) at a significantly lower rate than at present. Further, the regime’s rules are complex, and if a tax authority were to challenge or seek to disallow our claims (in whole or in part), for example by asserting that we do not (or the relevant expenditure does not) meet the technical conditions to be granted tax credits (or cash rebates), then such challenge or disallowance, if successful, could have a material impact on our cash-flow and financial performance. In addition, future changes to the U.K. R&D tax credit regime may mean that we no longer qualify for it or have a material impact on the extent to which we can make claims (or benefit from them).

Unsurrendered U.K. tax losses may be carried forward indefinitely to be offset against future taxable profits, subject to numerous utilization criteria and restrictions. The amount that can be offset each year is limited to $6.5 million (£5.0 million) plus an incremental 50% of U.K. taxable profits. After accounting for tax credits receivable, we had accumulated tax losses for carry forward in the United Kingdom of $237.0 million as of March 31, 2026 ($187.7 million as of March 31, 2025). However, in the event of a change in ownership of a U.K. company, certain provisions may apply to restrict the utilization of carried forward tax losses in future periods. These provisions apply where there is a major change in the nature or conduct of a trade in connection with the change in ownership. For the avoidance of doubt, we do not recognize a deferred tax asset in respect of the accumulated tax losses. In addition to our accumulated tax losses in the United Kingdom, we also had $50.5 million of accumulated tax losses as of March 31, 2026 ($48.7 million as of March 31, 2025), related to our operations in Germany for corporate income taxes. We also had $48.9 million of accumulated losses related to trade taxes in our German entity ($47.2 million as of March 31, 2025). We had a foreign tax expense in Germany of nil for the three months ended March 31, 2026 (three months ended March 31, 2025: nil). Tax losses in the United States were negligible.

In the event we generate revenues in the future, we may benefit from the U.K. “patent box” regime that allows profits attributable to revenues from patents or patented products to be taxed at an effective rate of 10%.

Value Added Tax, or VAT, is charged on all qualifying goods and services by VAT-registered businesses. Where U.K. VAT applies at a standard rate, an amount of 20% of goods and services is added to all sales invoices and is payable to the U.K. tax authorities. Similarly, U.K. VAT paid on purchase invoices may be reclaimable from the U.K. tax authorities.

Withholding tax is deductible from dividends, interest, lease of property, royalties, and other China-source passive income since we do not have an establishment or place of business in China.

Comparison of the three months ended March 31, 2026, and 2025

The following table summarizes the results of our operations for the three months ended March 31, 2026, and 2025 (in thousands).

Revenue

Revenue for the three months ended March 31, 2026 was $0.4 million, reflecting an increase of $0.3 million as compared to the same period in 2025 due to activity associated with the AstraZeneca collaboration.

Cost of sales

Cost of sales movement was negligible for the three months ended March 31, 2026, as compared to the same period in 2025. The change was due to activity associated with our collaboration agreements, which fluctuates based on the timing of activities and project progression.

Research and development costs

The following table summarizes our research and development costs for the three months ended March 31, 2026 and 2025, based on their classification (in thousands).

Research and development costs for the three months ended March 31, 2026 decreased by $11.7 million to $9.1 million. This change was mainly due to a decrease in contracted development costs of $10.3 million associated with the Phase 3 readiness for zerlasiran in 2025 as well as a decrease in personnel costs of $1.4 million mainly due to reduced headcount.

20

Contracted development costs for the three months ended March 31, 2026 decreased by $10.3 million to $4.3 million. The decrease was largely due to a decrease in costs related to contract manufacturing activities related to our zerlasiran Phase 3 readiness completed in 2025.

General and administrative expense

General and administrative expenses decreased by $0.7 million for the three months ended March 31, 2026 compared to the same period in 2025. These decreases were mainly due to an effort to reduce administrative costs.

Foreign currency gain (loss), net

As of January 1, 2026, the functional currency of our U.K. entity changed to USD and as a result, foreign currency activity included in net income for the three months ended March 31, 2026 was a loss of $0.5 million. In the prior year, foreign exchange gains and losses included in net income resulted primarily from foreign currency (USD and EUR) denominated bank accounts. The foreign exchange losses for the three months ended March 31, 2025 were primarily due to remeasurement of U.S. treasury bills held in USD to the related functional currency.

Other Income (expenses), net

Other income primarily relates to accretion from U.S. treasury bills and interest on cash accounts.

Benefit from R&D credit

Benefit from R&D tax credit relates to U.K. research and development tax credits. The decrease in benefit in the current year was mainly related to a reduction in research and development spend.

Taxation

There was no tax expense in the current or prior period.

Liquidity and Capital Resources

Overview

Since our inception, we have incurred significant operating losses and negative cash flows. We anticipate that we will continue to incur losses for the foreseeable future. We expect that our research and development and administrative expenses will increase in connection with conducting clinical trials and seeking marketing approval for our product candidates, as well as costs associated with operating as a public company.

As of March 31, 2026, we had cash, cash equivalents, and short-term investments of $70.1 million. We believe that our cash, cash equivalents, and short-term investments will be sufficient to fund our anticipated operating and capital expenditure requirements into 2028.

To date, we have financed our operations primarily through the issuances of our equity securities and from the receipt of upfront, milestone and research payments under collaboration agreements with third parties.

On October 15, 2021, we entered into an Open Market Sale Agreement, or the Sales Agreement, with Jefferies LLC, or Jefferies, pursuant to which we may offer and sell, from time to time, our ADSs through Jefferies. In 2024, we raised proceeds of $27.7 million before deducting $0.9 million in placement agent fees and other expenses, from sales of ADSs under the Sales Agreement.

On February 2, 2024, we entered into a securities purchase agreement, or the Purchase Agreement, with the purchasers named therein, or the Investors. Pursuant to the Purchase Agreement, we agreed to sell an aggregate of 5,714,286 of our ADSs to the Investors, at a purchase price equal to $21.00 per ADS, or the Private Placement. The

Purchase Agreement contained customary representations and warranties from us and the investors and customary closing conditions. The closing of the Private Placement occurred on February 7, 2024, and we received aggregate gross proceeds from the Private Placement of approximately $120.0 million before deducting $7.7 million in placement agent fees and other expenses.

We have no ongoing material financing commitments, such as lines of credit or guarantees, that are expected to affect our liquidity over the next five years, other than operating leases.

Refer to Note 2.5 in the notes to our condensed consolidated financial statements appearing elsewhere in this Quarterly Report on Form 10-Q for additional discussion of liquidity and capital resources.

Cash Flows

The following table summarizes the results of our cash flows for the three months ended March 31, 2026 and 2025.

Operating activities

Net cash outflow from operating activities increased by $3.3 million for the three months ended March 31, 2026, as compared with the same period in 2025. This increase was mainly due to the receipt of $11.0 million related to the 2023 R&D benefit in the three months ended March 31, 2025, while no related claim was received in 2026. This was offset by a reduction in research and development spend in 2026.

Investing activities

Net cash inflow from investing activities relates to redemptions of U.S. treasury bills, offset by purchases for the three months ended March 31, 2026. The same period in 2025 reflected $70.1 million in purchases of U.S. treasury bills offset by $25.7 million in redemptions.

Financing activities

Cash flows from financing activities were negligible for the periods ended March 31, 2026 and 2025.

Operating and Capital Expenditure Requirements

We have not achieved profitability on an annual basis since our inception, and we expect to incur net losses in the future. We expect to continue to incur expenses in connection with our ongoing research and development activities related to our product candidates, including outsourced manufacturing activities and other associated costs. We also expect to continue to incur costs associated with operating as a domestic filer listed on Nasdaq.

Additionally, as a public company, we incur significant additional audit, legal and other expenses. We believe that our existing capital resources will be sufficient to fund our operations, including currently anticipated research and development activities and planned capital spending, at least for the next twelve months.

Our future funding requirements will depend on many factors, including but not limited to:

• the scope, rate of progress and cost of our clinical trials, preclinical programs and other related activities;
• the extent of success in our early preclinical and clinical-stage research programs, which will determine the amount of funding required to further the development of our product candidates;
• the cost of manufacturing clinical supplies and establishing commercial supplies of our product candidates and any products that we may develop;
• the costs involved in filing and prosecuting patent applications and enforcing and defending potential patent claims;
• the outcome, timing and cost of regulatory approvals of our product candidates;
• the cost and timing of establishing sales, marketing and distribution capabilities; and
• the costs of hiring additional skilled employees to support our growth and the related costs of leasing additional office space.

Contractual Obligations and Commitments

The following table summarizes our contractual commitments and obligations as of March 31, 2026 and December 31, 2025.

The lease liability recognized on the balance sheet comprises our London office. Our balance sheet also reflects two short-term leases in Berlin, Germany and a lease in New Jersey, United States, neither of which is included in the "lease liability" line of the table above. Both leases in Berlin are on a rolling contract basis with either party being able to end the lease with a cancellation notice period of 11.5 months, while the leases in the United States are on a rolling contract basis with a notice period of three months, thus allowing the exemption for short-term leases.

At March 31, 2026, we had a gross commitment on our office rental in Berlin, Germany and in the United States equal to an aggregate of $0.6 million in the next year. No amounts are payable after more than one year.

We have agreed to make payments to CROs and manufacturers under various CRO and manufacturing agreements that generally provide for our ability to terminate on short notice. We have not included any such contingent payment obligations in the table above as the amount, timing and likelihood of such payments are not fixed or determinable.

Critical Accounting Policies and Critical Accounting Estimates

Our financial statements are prepared in accordance with U.S. GAAP. The preparation of the financial statements and related disclosures requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, costs and expenses, and the disclosure of contingent assets and liabilities in our financial statements. We base our estimates on historical experience, known trends and events and various other factors that management believes are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Management evaluates estimates and assumptions on a periodic basis. Our actual results may differ from these estimates.

While our significant accounting policies are described in more detail in the notes to our condensed consolidated financial statements appearing elsewhere in this Quarterly Report on Form 10-Q, we believe the following accounting policies to be most critical to the judgments and estimates used in the preparation of our condensed consolidated financial statements.

Revenue Recognition under Collaboration Agreements

During the three months ended March 31, 2026 and 2025, our revenue from collaboration agreements was derived from the AstraZeneca collaboration.

We have out-licensed the rights to some of our intellectual property associated with our siRNA stabilization chemistry technology to AstraZeneca in the context of a Research Collaboration, Option and License Agreement dated March 24, 2020, under which we and AstraZeneca will collaborate to discover, develop and commercialize siRNA therapeutics for the treatment of cardiovascular, renal, metabolic and respiratory diseases. AstraZeneca made an upfront cash payment of $60.0 million, of which $20.0 million was paid in May 2020 and the remaining $40.0 million was paid in May 2021. The upfront payment has been allocated evenly between the ten targets on the basis of a benchmarking exercise that took into account the standalone selling price per target, of similar precedent transactions that had been publicly announced by comparable companies. Subsequent milestones are allocated to the target to which they are related. The upfront and milestone payments will be recognized as revenue as the services are provided. We anticipate initiating work on up to five targets in the early stages of the collaboration, with AstraZeneca having the option to extend the collaboration to a further five targets. Under the collaboration, utilizing our technology, we are responsible for designing siRNA molecules against gene targets selected by AstraZeneca, and for manufacturing of material to support GLP toxicology studies and phase 1 clinical trials. We and AstraZeneca will collaborate during the discovery phase, and AstraZeneca will lead clinical development and commercialization of molecules arising from the collaboration. For each target selected under the collaboration, we will be eligible to receive up to $140.0 million in milestone payments upon the achievement of milestones relating to the initiation of specified clinical trials, the acceptance of specified regulatory filings and the first commercial sale in specified jurisdictions. AstraZeneca has the right to terminate the agreement in its entirety or on a target-by-target basis, for any reason upon specified prior written notice to us. We may terminate the agreement on a target-by-target basis in the event that AstraZeneca begins a legal or administrative proceeding challenging the patentability, validity, ownership or enforceability of our patents. Either party may terminate the agreement on a target-by-target basis upon a material breach by the other party that is not cured within a specified period after receiving written notice, or in its entirety upon giving written notice following the other party’s bankruptcy, insolvency or similar instance. The license of the intellectual property and the R&D services are not distinct, as AstraZeneca cannot benefit from the intellectual property absent the R&D services, as those R&D services are used to discover and develop a drug candidate and to enhance the value in the underlying intellectual property, which could not be performed by another party, indicating that the two are highly interrelated. On this basis, we have concluded that there is a single performance obligation covering both the R&D services and the license of the intellectual property in respect of each target (i.e., one for the initial target and one for each additional optioned complement-mediated disease target). We recognize revenue over the duration of the contract based on an input method based on percentage of cost incurred.

For all the collaboration agreements listed above, as there is only a single performance obligation per target, the revenue for each element of consideration will be recognized over the contract period based on a cost-to-cost method, which is considered to be the best available measure of our effort during the contract period. The total cost estimate for the contract includes costs expected to be incurred during the contract period. Other variable elements of consideration will only begin to be recognized when it is considered highly probable that a significant reversal of the amounts will not occur.

For the three months ended March 31, 2026 and 2025, we determined actual costs and forecast costs for the remainder of the contract. We calculated total contract costs across the contract term, including costs that will be reimbursed to us, and costs incurred to date as a percentage of total contract costs. We multiplied this percentage by the consideration deemed highly probable of not having a significant reversal, calculating the cumulative revenue to be recognized. When variable consideration increases due to a further milestone becoming highly probable that a significant reversal of revenue will not occur, a catch-up in revenue is recorded to reflect efforts already expended by us up to that point. In the three months ended March 31, 2026, the estimated forecasted cost for partnered programs was not material and the related judgment was not significant.

Recognition of Clinical Trial Expenses

As part of the process of preparing our condensed consolidated financial statements, we may be required to estimate accrued expenses related to our preclinical studies and clinical trials. To obtain reasonable estimates, we review open contracts and purchase orders. In addition, we communicate with applicable personnel in order to identify services that have been performed, but for which we have not yet been invoiced. In most cases, our vendors provide us with monthly invoices in arrears for services performed. We confirm our estimates with these vendors and make adjustments as needed. Examples of our accrued expenses include fees paid to CROs for services performed on preclinical studies and clinical trials and fees paid for professional services.

Recent Accounting Pronouncements

We discuss the effect of recently issued and adopted pronouncements in Note 2.6, "Recently Issued Accounting Pronouncements" to the condensed consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q and Note 2.20, “Summary of Significant Accounting Policies” to our audited consolidated financial statements in our Annual Report on Form 10-K for the year ended December 31, 2025.

We are a smaller reporting company as defined in Item 10(f)(1) of Regulation S-K. As a result, pursuant to Item 305(e) of Regulation S-K, we are not required to provide the information required by this Item 3.

Disclosure Controls and Procedures

We maintain “disclosure controls and procedures,” as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended, or the Exchange Act, that are designed to ensure that information required to be disclosed by an issuer in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported, within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by an issuer in the reports that it files or submits under the Exchange Act is accumulated and communicated to our management, including our Interim Principal Executive Officer and Chief Financial Officer, as appropriate, to allow timely decisions regarding required disclosure.

Our management, with the participation of our Interim Principal Executive Officer and Chief Financial Officer, has evaluated the effectiveness of our disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) as of March 31, 2026. Based on such evaluation, our Interim Principal Executive Officer and Chief Financial Officer have concluded that, as of March 31, 2026, our disclosure controls and procedures were effective at the reasonable assurance level.

Changes in Internal Control Over Financial Reporting

There have been no changes in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) that occurred during the three months ended March 31, 2026, that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

Our business has significant risks. In addition to the other information set forth in this Quarterly Report on Form 10-Q, you should carefully consider the risks described in Part I, Item 1A. “Risk Factors” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the Securities and Exchange

Commission, or SEC, on March 5, 2026. These are not the only risks facing our business. Other risks and uncertainties that we are not currently aware of or that we currently consider immaterial also may materially adversely affect our business, financial condition and future results. Risks we have identified but currently consider immaterial could still also materially adversely affect our business, financial condition and future results of operations if our assumptions about those risks are incorrect or if circumstances change.