Annual Report for Fiscal Year Ending December 31, 2025 (Form 10-K)

Management’s Discussion and Analysis of Financial Condition and Results of Operations.

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our consolidated financial statements and related notes included elsewhere in this Annual Report on Form 10-K. In addition to historical financial information, this discussion contains forward-looking statements based upon current expectations that involve risks and uncertainties. Our actual results could differ materially from those anticipated in these forward-looking statements as a result of various factors, including those set forth under “Special Note Regarding Forward-Looking Statements” and “Risk Factors” and elsewhere in this Annual Report on Form 10-K. Our fiscal year ends on December 31 each year.

Overview

We are a clinical-stage biotechnology company focused on developing novel therapeutics to address unmet medical needs in liver diseases and viral infections, including in the areas of chronic hepatitis B virus (HBV) infection, metabolic dysfunction-associated steatohepatitis (MASH), and coronavirus infections (e.g., SARS-CoV-2, SARS-CoV, MERS-CoV, and other related infections) as well as obesity. The Aligos team has a demonstrated track record of success in drug development and medicinal chemistry in liver and viral diseases, resulting in three potential best-in-class drug candidates currently in clinical development.

Our pipeline of drug candidates includes pevifoscorvir sodium (previously known as ALG-000184) for chronic HBV infection, ALG-055009 for MASH and obesity, ALG-097558 for coronavirus infections, and a portfolio of preclinical programs. Pevifoscorvir sodium is our potential best-/first-in-class Capsid Assembly Modulator (CAM-E) for chronic HBV infection which has shown in pre-clinical testing to have enhanced pharmacologic properties vs. competitor CAM-E drugs and greater HBV DNA suppression compared to the standard of care, nucleos(t)ide analogs (NAs), and has shown multi-log10reductions in viral antigens in Phase 1 clinical studies conducted to date. ALG-055009 is our potential best-in-class thyroid hormone receptor beta (THR-β) agonist for obesity and MASH with pharmacologic properties that appear to be enhanced based on data to date vs. competitor THR-β agonists. Phase 2a topline data in MASH demonstrated that ALG-055009 dose groups met the primary endpoint with statistically significant reductions in liver fat at Week 12 as measured by MRI-PDFF in subjects with presumed MASH. Recently presented nonclinical data suggests synergistic fat mass loss in combination with incretin receptor agonists in diet induced obese (DIO) mice. ALG-097558 is our potential best-in-class small molecule pan-coronavirus 3CL protease inhibitor (PI), which has been at least 3-fold more potent in cell-based assays of coronavirus infection than other approved CoV PIs and we believe can be dosed twice daily without the requirement for ritonavir co-dosing based on Phase 1 clinical studies conducted to date.

Pevifoscorvir sodium: Potential best-in-class small molecule CAM-E for chronic hepatitis B virus infection

Our primary area of focus seeks to enhance the viral suppression and rate of functional cure for chronic HBV infection, which often results in life-threatening conditions such as cirrhosis, end-stage liver disease, and the most common form of liver cancer, hepatocellular carcinoma (HCC). To achieve this, we are developing a portfolio of differentiated chronic HBV infection drug candidates, including a small molecule CAM that results in the production of empty viral capsids.

In 2018, we in-licensed a lead drug candidate (GLP-26) and the associated IP for a CAM-E from the laboratory of Professor Raymond Schinazi at Emory University. Our scientists optimized this lead drug candidate to discover the highly potent CAM-E, ALG-001075, which was further optimized to the prodrug pevifoscorvir sodium. Based on pre-clinical data to date, pevifoscorvir sodium has superior DMPK properties with enhanced absorption and high liver uptake, with a ~2-300-fold improvement in in vitro potency compared to other known CAMs. CAM-Es are a class of small molecule antiviral agents that accelerate HBV capsid assembly and inhibit pgRNA encapsidation (1st MOA), resulting in empty viral capsids and lower circulating HBV DNA and RNA levels. CAM-Es are also believed to prevent the establishment of cccDNA (2nd MOA), a major factor for the persistence of HBV infection which can be assessed by circulating HBV antigen levels (HBsAg, HBcrAg, and HBeAg). In clinical trials, competitor CAM-Es have shown reductions in HBV DNA and RNA (1st MOA), but have rarely or inconsistently shown reductions in HBV antigens (2nd MOA). There have also been observations of the emergence of viral CAM-E drug resistance with competitor compounds.

A multi-part Phase 1 study is complete, with evaluation of the safety, tolerability, and pharmacokinetic profile of pevifoscorvir sodium in HVs. Additionally, a dose-ranging phase assessing the safety, pharmacokinetics (PK), and antiviral activity of 10-300 mg doses of pevifoscorvir sodium administered over 28 days in untreated HBeAg+/- subjects with chronic HBV infection has also been completed. In these study phases, pevifoscorvir

sodium was found to be well tolerated with a favorable PK profile and demonstrated potentially best-in-class multi-log10HBV DNA and RNA reductions at all doses tested, as well as HBV surface antigen (HBsAg) reductions in a subset of HBeAg+ subjects receiving 100 mg or 300 mg of pevifoscorvir sodium (Hou et al, AASLD 2022). Based on the favorable profile observed with dosing up to 300 mg of pevifoscorvir sodium for 28 days, additional Phase 1 studies evaluated the risk-benefit profile of pevifoscorvir sodium at doses of 300 mg, with or without entecavir (ETV) therapy, for up to 96 weeks in HBeAg+ and HBeAg- subjects with chronic HBV infection. Data from these cohorts (Yuen et al., AASLD 2025) have been presented, showing that pevifoscorvir sodium, administered for up to 96 weeks, was well tolerated, exhibited a favorable PK profile, and suggested potentially best-in-class potent and durable antiviral activity.

Data from this study following an oral daily dose of 300 mg pevifoscorvir sodium monotherapy in HBeAg+ subjects demonstrated sustained HBV DNA suppression (

Additionally, HBV RNA level achieved < LLOQ (10 copies/mL) in all HBeAg+ and HBeAg- subjects by Week 52 and Week 6, respectively. Furthermore, concurrent multi-log10reductions in HBV antigens (HBsAg, HBeAg, and HBcrAg) in HBeAg+ subjects and HBcrAg decline in HBeAg- subjects were observed, suggesting the potential inhibition of cccDNA establishment by CAM-E 2nd mechanism of action of pevifoscorvir sodium.

Further, data presented at AASLD’s The Liver Meeting® 2025 highlighted outcomes for treatment-naïve or currently not treated HBeAg+ and HBeAg- subjects who completed 96 weeks of 300 mg pevifoscorvir sodium monotherapy, followed by 8 weeks of nucleos(t)ide analog (NA) monotherapy. Reductions in HBV DNA, HBV antigens, and HBV RNA were largely maintained during the NA-only 8-week follow-up period. Notably, viral biomarkers such as HBV antigens and HBV RNA are typically unaffected by NA therapy, suggesting that pevifoscorvir sodium may reduce the cccDNA pool through engagement of its secondary mechanism of action (Yuen et al., AASLD 2025).

Additionally, preclinical in vitro data demonstrated that ALG-001075, the active parent moiety of pevifoscorvir sodium, can prevent cccDNA formation and HBV DNA integration. This finding is further supported by cell-based studies, which showed prevention of cccDNA establishment and HBV DNA integration following treatment with ALG-001075 (Verheyen, et. al. AASLD 2025).

With the completion of the 96 week Phase 1 study, we initiated the Phase 2 B-SUPREME study (NCT06963710), which is designed as a randomized, double-blind, active-controlled multicenter study evaluating the safety and efficacy of pevifoscorvir sodium monotherapy compared with tenofovir disoproxil fumarate for 48 weeks in approximately 200 currently untreated HBeAg+ and HBeAg- adult subjects with chronic HBV infection. The primary endpoint in the HBeAg+ arm is HBV DNA

The first interim analysis is expected to occur in the first half of 2026. The first protocol defined interim analysis includes approximately 60% (or 36) HBeAg- participants that complete 12 weeks of the treatment period. This enrollment milestone occurred in Q4 2025.

A second protocol defined interim analysis is planned when approximately 50% (or 55) HBeAg+ participants complete 24 weeks of the treatment period. This enrollment milestone occurred in January 2026. This interim analysis is expected to occur in the second half of 2026.

To preserve study integrity and comply with FDA regulatory requirements, we will remain blinded to subject-level data and will receive insights from the Data Safety Monitoring Board on protocol-specified assessments, including the potential for sample size re-estimation at each interim analysis.

Topline data for the Phase 2 B-SUPREME study are expected in 2027.

Compared to Phase 3 studies with the current standard of care nucleos(t)ide analogs (NAs), tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) (Buti et al., Lancet Gastro, 2016; Chen et al., Lancet Gastro 2016), these Phase 1 data to date suggest, subject to confirmation via further study, that pevifoscorvir sodium treatment may be superior to NAs in HBeAg+/- subjects in achieving HBV DNA levels < LLOQ (10 IU/mL) after 48 weeks on treatment. Chronic suppressive therapy of HBV DNA levels is a validated approval pathway in chronic HBV infection (Food and Drug Administration (FDA) Guidance, Chronic Hepatitis B Virus Infection: Developing Drugs for Treatment Guidance for Industry, April 2022 – Section III.B.1.a). We have received affirmative feedback from the FDA, the Committee for Medicinal Products for Human Use (CHMP: EU) and the National Medical Products Administration (NMPA: China) supporting subsequent studies utilizing the chronic suppressive therapy pathway for pevifoscorvir sodium. Our ongoing Phase 2 B-SUPREME study is being conducted to test superiority to standard of care NA treatment (HBV DNA levels

We are also exploring additional ways to potentially treat patients with chronic HBV infection, including our antisense oligonucleotide (ASO) platform which utilizes novel monomers that could potentially reduce ASO toxicity and improve ASO liver to kidney ratios. Along with our partner Xiamen Amoytop Biotech Co., Ltd. (Amoytop), ALG-170675 was recently selected to proceed into IND-enabling studies. Current costs for development in China are being funded by Amoytop, who maintain rights in China, Taiwan, Hong Kong and Macau. This next-generation ASO works via two mechanisms of action. It targets and destroys HBsAg mRNA and activates the immune response through TLR-8 agonism.

Additionally, we are pursuing a novel strategy for a potential cure for hepatitis delta virus (HDV) coinfection by utilizing a proprietary ASO approach targeting the destruction of the viral genome. Ongoing work is aimed at the selection of a clinical development candidate.

ALG-055009: Potential best-in-class small molecule THR-β agonist for metabolic dysfunction-associated steatohepatitis and obesity

Obesity is a complex disease caused by an overabundance of body fat that increases the risk of other comorbidities, such as MASH. MASH is a complex, chronic liver disease which is a leading cause of liver-related morbidity including cirrhosis, hepatocellular carcinoma, liver transplant, and end-stage liver disease. In 2014, the first GLP-1 receptor agonist, liraglutide, was approved for weight loss and in 2024, the FDA approved resmetirom, a THR-β agonist, as the first drug for the treatment of MASH. However, additional agents in these classes are needed to address remaining unmet needs, including the potential for improved efficacy and a more favorable risk-benefit profile. To achieve this, ALG-055009 has been purposefully designed to exhibit significantly greater potency (approximately 50-fold higher compared to resmetirom in head-to-head in vitro studies) and enhanced β selectivity, along with optimized pharmacologic properties to deliver a potentially improved PK profile compared to other THR-β agonists. We believe these advantages position ALG-055009 as a strong candidate to become a best-in-class THR-β agonist.

A first-in-human Phase 1 study of ALG-055009 in MASH in HVs (oral single ascending doses (SAD)) and in subjects with hyperlipidemia (14 oral daily multiple ascending doses (MAD)) has been completed. Clinical data after single doses up to 4 mg and multiple doses up to 1 mg showed that ALG-055009 was well tolerated, had dose proportional PK with low intersubject variability, and demonstrated expected thyromimetic effects (i.e., generally dose proportional increases in sex hormone binding globulin and decreases in various atherogenic lipids and thyroid hormones without any clinical evidence of thyroid dysfunction). We also evaluated relative bioavailability where we showed the soft gelatin capsules used in the Phase 2a study described below delivered similar exposures compared to the solution formulation used in the SAD/MAD parts of the Phase 1 study; we observed low intersubject PK variability and there was no evidence of a meaningful food effect.

Based on these promising Phase 1 data, we conducted the Phase 2a HERALD study (NCT06342947) at sites across the United States. The study was a 12-week randomized, double-blind, placebo-controlled trial evaluating 4 doses (0.3 mg, 0.5 mg, 0.7 mg, and 0.9 mg) of ALG-055009 vs. placebo in 102 subjects with presumed MASH and liver fibrosis at stages 1-3 (F1-F3). The primary endpoint of this study was percent relative change in

liver fat content by MRI-PDFF at Week 12. This study also evaluated the safety and PK of ALG-055009 treatment and its effect on multiple other efficacy biomarkers, including other non-invasive tests previously shown to be impacted by treatment with THR-β agonists. We announced positive topline data from this study in 2024, demonstrating that ALG-055009 dose groups were well-tolerated and met the primary endpoint. Specifically, doses of 0.5 mg to 0.9 mg ALG-055009 demonstrated statistically significant reductions in liver fat at Week 12, with placebo-adjusted median relative reductions up to 46.2% as measured by MRI-PDFF. Up to 70% of subjects achieved ≥30% relative reduction in liver fat compared to baseline. Eighteen subjects who were on stable GLP-1 agonist therapy qualified for enrollment in the study, with liver fat content meeting the inclusion criteria of ≥10% at baseline as measured by MRI-PDFF. Notably, 11 of 14 subjects on stable GLP-1 agonists treated with ALG-055009 had liver fat decreases, whereas 4 of 4 subjects on stable GLP-1 agonists treated with placebo had increases in liver fat over the 12-week dosing period (Loomba et al, AASLD 2024).

In the Phase 2a HERALD study, ALG-055009 demonstrated a favorable tolerability profile with no evidence of clinical hyper/hypothyroidism. Incidence of gastrointestinal-related treatment emergent adverse events were similar in ALG-055009 dose groups compared to placebo. Specifically, similar rates of diarrhea were observed in ALG-055009 dose groups compared to placebo, with no dose-response. Significant reductions in atherogenic lipids, including LDL-C, lipoprotein (a), and apolipoprotein B, were also observed (Loomba et al, AASLD 2024).

Preclinical and clinical findings reported by other companies have suggested that THR-β agonists can significantly enhance weight loss when administered in combination with incretin receptor agonists (RAs) for the treatment of obesity.

Recently presented in vivo data in diet induced obese (DIO) mice treated with SEMA, TIRZEP, or a combination of ALG-055009 and SEMA or TIRZEP for 28 days demonstrated synergistic weight loss in the combination groups compared to monotherapy groups. SEMA monotherapy resulted in a maximum of 23.9 ±2.6% body weight loss, while the combination of SEMA and ALG-055009 had an additional 8.6% decrease for a maximum 33% body weight loss. The low and high doses of TIRZEP led to maximum of 27.1 ±2.7% and 34.4 ±1.6% body weight loss, respectively. Combination of TIRZEP (low) or TIRZEP (high) with ALG-055009 induced an additional 11.7% and 5.8% decrease for a maximum of 39% and 40% body weight loss, respectively.

Furthermore, the additional weight loss in the combination therapy of either incretin receptor agonist and ALG-055009 was mainly due to additional loss of fat mass, with no significant effect on lean mass or food consumption as compared to incretin receptor agonist monotherapy. These preclinical data suggest a potentially significant benefit of adding ALG-055009 to an incretin receptor agonist therapy for weight loss, especially in combination with a low-dose of a potent molecule, such as tirzepatide.

We believe ALG-055009 warrants further development as a potential treatment for both obesity and MASH. We are continuing to evaluate a variety of options to fund continued development, including potential out-licensing.

ALG-097558: Potential best-in-class small molecule ritonavir-free protease inhibitor for pan-coronavirus

Another area of focus is to develop drug candidates with pan-coronavirus antiviral activity, including against Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for COVID-19. In this area of focus, we are exploring small molecule coronavirus 3CL protease inhibitors (PIs) in collaboration with the Rega Institute at Katholieke Universiteit Leuven (KU Leuven), the Center for Innovation and Stimulation of Drug Discovery (CISTIM) and the Centre for Drug Design and Discovery (CD3). This collaboration led to the discovery of ALG-097558 which has completed a Phase 1 first-in-human evaluation in HVs and advanced into a clinical trial evaluating the compound in high-risk COVID-19 patients.

ALG-097558 has been shown in preclinical studies to be at least 3-fold more potent than nirmatrelvir and other PIs in clinical development against a panel of SARS-CoV-2 variants (including Omicron). It also has demonstrated broad pan-coronavirus activity, including against SARS-CoV-1 and MERS-CoV in preclinical studies. In the first-in-human Phase 1 clinical study, single doses up to 2000 mg and multiple doses up to 800 mg Q12H for 7 days were well tolerated with an acceptable PK profile that suggests ritonavir boosting may not be required. Furthermore, the absence of a clinically relevant DDI with midazolam suggests that ALG-097558 may be shown to be appropriate for co-administration with CYP3A4 substrates (NCT05840952). Based on these Phase 1 data (Wilkes et al., RespiDart, 2024), the projected efficacious dose range to treat SARS-CoV-2 is 200-600 mg ALG-097558 Q12 x 5 days, without the need for ritonavir coadministration.

A Phase 2 study of ALG-097558 began in 2024. The AGILE trial, a United Kingdom government-supported platform trial (MRC and Wellcome Trust funding), is sponsoring and performing a study in standard and high-risk COVID-19 patients evaluating ALG-097558 as monotherapy or in combination with remdesivir (NCT04746183). We expect that future development of ALG-097558 will be funded by external sources, including public funding sources as described below.

Preclinical activities for our coronavirus program were partially funded through a grant from the National Institutes of Health (NIH) and the National Institute of Allergy and Infectious Diseases (NIAID) Antiviral Drug Discovery (AViDD) Centers for Pathogens of Pandemic Concern program through the Metropolitan AntiViral Drug Accelerator (MAVDA) consortium. Specific clinical and nonclinical studies for the ALG-097558 program and the follow up compound, are now also being funded with federal funds from the NIAID, NIH, Department of Health and Human Services, under Contract No. 75N93023C00052. We filed an IND in the third quarter of 2024. We expect to receive approximately $15.3 million in funds across these two NIH awards and contracts to support these activities. To date, these funds have not been impacted by any changes at the NIH or NIAID. We are also seeking additional external funding (e.g., from governmental agencies) and/or collaborations (e.g., platform trials) to support future studies as we advance ALG-097558 for the treatment of COVID-19 and future coronavirus pandemics.

Components of our results of operations

Revenue

Our revenues consist of the following:

Collaboration revenueincluded recognition of our upfront payments pursuant to an agreement and amendment with Merck Sharp & Dohme Corp, that were terminated in prior years. In order to record collaboration revenue, we utilized an input method to recognize revenue over time as costs were incurred.

Customer revenueincludes recognition of revenue generated from research and development services under third-party contracts with customers. In order to record customer revenue, we utilize an input method to recognize revenue over time as costs are incurred.

Operating expenses

Our operating expenses since inception have consisted solely of research and development costs and general and administrative costs.

Research and development expenses

We expect our expenses to increase substantially in connection with our ongoing clinical development activities related to our chronic HBV infection drug candidate pevifoscorvir sodium. We rely substantially on third parties to conduct our discovery activities, nonclinical studies, clinical trials and manufacturing. We estimate research and development expenses based on estimates of services performed, and rely on third party contractors and vendors to provide us with timely and accurate estimates of expenses of services performed to assist us in these estimates. A portion of our research and development expenses are based on contractual milestones. Research and development costs consist primarily of costs incurred for the identification and development of our drug candidates through our technology platforms, which include:

We expense research and development costs as the services are performed or the goods are received. Non-refundable payments for goods or services that will be used for future research and development activities are deferred and capitalized. Such amounts are recognized as an expense as the goods are delivered or the related services are performed until it is no longer expected that the goods will be delivered or the services will be rendered.

Our research and development costs may increase in future periods as we continue to invest in research and development activities and advance our nonclinical and clinical programs through clinical development. The process of conducting nonclinical studies and, eventually, clinical trials necessary to obtain regulatory approval is costly and time consuming, and the successful development of our drug candidates is highly uncertain. As a result, we are unable to determine the duration and completion costs of our research and development projects or clinical trials or if and to what extent we will generate revenue from the commercialization and sale of any of our drug candidates.

General and administrative expenses

General and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation, for personnel in our executive, finance, corporate, legal and business development and administrative functions. General and administrative expenses also include legal fees relating to patent and corporate matters; professional fees for accounting, auditing, tax and consulting services; insurance costs; travel expenses; and facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs not otherwise classified as research and development costs.

Our general and administrative expenses may increase in the future as we increase our general and administrative personnel headcount to support personnel in research and development and to support our operations generally as we increase our research and development activities and activities related to the potential commercialization of our drug candidates. We may also incur increased expenses associated with operating as a public company, including costs of accounting, audit, legal, regulatory and tax-related services associated with maintaining compliance with exchange listing rules and requirements of the Securities and Exchange Commission (the SEC), director and officer insurance costs, and investor and public relations costs.

Interest and other income, net

Interest and other income, net comprises interest income, net and other income, net. Interest income, net primarily consists of interest earned on our cash, cash equivalents, and investments. Other income, net includes investments and foreign currency gains/losses.

Change in fair value of 2023 Common Warrants

The change in fair value of 2023 Common Warrants includes the remeasurement of the 2023 Common Warrants using the Black Scholes option pricing model at each reporting period.

Income tax provision

Since our inception in 2018, we have not recorded any U.S. federal or state income tax benefits for the net losses we have incurred in any year or for our earned research and development tax credits, due to our uncertainty of realizing a benefit from those items. As of December 31, 2025, we had federal net operating loss (NOL) carryforwards of $92.5 million available to reduce taxable income and these NOLs can be carried forward indefinitely. We have state NOL carryforwards of $105.7 million as of December 31, 2025, available to reduce future state taxable income, which expire at various dates beginning in 2043. As of December 31, 2025, we also had federal and state research and development tax credit carryforwards of $3.5 million and $2.2 million, respectively. The federal research and development tax credit carryforwards begin to expire in 2043, while the state research and development tax credit carryforwards can be carried forward indefinitely. As of December 31, 2025, the Company had $3.2 million of Australian NOL carryforwards and $0.7 million of Australian research and development tax credit carryforwards available. The Australian NOL carryforwards and research and development tax credits have no expiration date.

On July 4, 2025, the One Big Beautiful Bill Act (OBBBA) was signed into law. The effects of this legislation include extending and modifying certain key provisions of the Tax Cuts and Jobs Act enacted in December 2017 (both domestic and international). The corporate tax rate remains unchanged but bonus, depreciation and an adjustment to the interest limitation were retroactive to January 1, 2025. The OBBBA makes additional changes to international tax provisions, including substantive changes to existing Global Intangible Low Tax Income, foreign-derived intangible income, and base erosion and anti-abuse tax provisions. These changes are effective for taxable years after 2025. The impact of this legislation does not materially impact the current period nor do we expect it to have a material impact on our tax positions for future years.

Under Sections 382 and 383 of the Internal Revenue Code (Code), and corresponding provisions of state law, if a corporation undergoes an “ownership change” (generally defined as a greater than 50 percentage point change (by value) in its equity ownership over a rolling three-year period), our ability to use our pre-change NOL carryforwards and other pre-change tax attributes to offset its post-change income may be limited. We performed a Code Section 382 analysis in 2025 and determined no further ownership change.

We may experience additional ownership changes as a result of subsequent shifts in our stock ownership, some of which may be outside of our control. In the future, if we earn net taxable income, our ability to use our pre-change net operating loss carryforwards or other tax attributes to offset U.S. federal taxable income may be subject to limitations, which could potentially result in increased future tax liability to us and could adversely affect our business, results of operations, and cash flows. In addition, under current tax law, federal NOL carryforwards generated in periods after December 31, 2017, may be carried forward indefinitely but, may only be used to offset 80% of our taxable income.

Results of operations

Comparison of the years ended December 31, 2025 and 2024

The following table summarizes our operating expenses for the years ended December 31, 2025 and 2024:

Revenue from collaborations

Revenue from collaborations was $0.3 million for the year ended December 31, 2024. There was no collaboration revenue for the year ended December 31, 2025. This is due to the completion of the amended collaboration agreement with Merck ended in May 2024.

Revenue from customers

Revenue from customers was $2.2 million for the year ended December 31, 2025, compared to $3.6 million for the year ended December 31, 2024, a decrease of $1.4 million, primarily due to the collaboration and license agreement with Amoytop, the collaboration portion of which ended in November 2025. Refer to Note 10, Revenue from Contracts with Customers for further information.

Research and development expenses

We track direct external research and development expenses on a program-specific basis (chronic HBV infection, MASH, coronaviruses and early-stage programs). The following table summarizes these research and development costs (in thousands):

Research and development expenses were $69.5 million for the year ended December 31, 2025, compared to $70.3 million for the year ended December 31, 2024, a decrease of $0.8 million. This is primarily due to a decrease of $1.8 million in third-party expenses due to increased government funds received for the coronavirus program which offset related costs. There was also a decrease of $0.2 million in depreciation. Offsetting this were increases of $0.4 million in employee-related costs, $0.4 million in facility expenses, and $0.4 million in travel and recruiting expenses.

We expect research and development expenses will increase in future periods as we continue to focus on advancing our clinical trials for pevifoscorvir sodium.

General and administrative expenses

General and administrative expenses were $20.7 million for the year ended December 31, 2025, compared to $22.8 million for the year ended December 31, 2024, a decrease of $2.1 million. This is due to a decrease of $2.1 million of third-party expenses primarily due to reduced legal and IP spend, and a decrease of $0.3 million in facility expenses. This was partially offset by an increase of $0.1 million in depreciation and $0.2 million in travel and recruiting costs.

We expect general and administrative expenses will increase in future periods due to increased activity in our research and development group, which will require more resources and additional activities in our general and administration group.

Interest income, net

Interest income, net was $2.2 million for the year ended December 31, 2025 compared to $1.7 million for the year ended December 31, 2024, an increase of approximately $0.5 million, primarily due to a higher average investment balance.

Other income, net

Other income, net was an income of $1.8 million for the year ended December 31, 2025 compared to income of $2.7 million for the year ended December 31, 2024, a decrease of $1.0 million. The difference was due to a decrease in the accretion of short-term investments.

Change in fair value of 2023 Common Warrants

The change in fair value of 2023 Common Warrants was an income of $60.2 million for the year ended December 31, 2025 compared to an expense of $46.1 million for the year ended December 31, 2024, a difference of $106.3 million. The increase was due to a change in the fair value of the 2023 Common Warrants measured using the Black Scholes option pricing model remeasured at each reporting period.

Liquidity and capital resources

Liquidity

We have incurred net losses and negative cash flows from operations in each year since our formation in February 2018. Our net losses were $24.2 million and $131.2 million for the years ended December 31, 2025 and 2024, respectively. We have had no revenue from product sales. We have not yet commercialized any products and we do not expect to generate revenue from sales of any drug candidates for at least several years, if ever.

Our operations have been financed primarily by net proceeds from the sale and issuance of our convertible preferred stock, net proceeds from our IPO, and the issuance of convertible debt.

In October 2023, we completed a PIPE offering and entered into a securities purchase agreement (the 2023 Securities Purchase Agreement) pursuant to which we issued 1,257,168 shares of our common stock, par value $0.0001 per share, pre-funded warrants to purchase an aggregate of 3,242,018 shares of our common stock (the 2023 Pre-Funded Warrants), and common warrants to purchase an aggregate of 2,249,680 shares of our common stock (the 2023 Common Warrants, and together with the 2023 Pre-Funded Warrants, the 2023 Warrants). Each 2023 Warrant is exercisable for one share of common stock. We received gross proceeds of $92.1 million, and after deducting the placement agent fees and expenses and offering costs, net proceeds were $86.2 million.

In February 2025, we entered into a securities purchase agreement (the 2025 Securities Purchase Agreement) with certain investors named therein (the Purchasers) pursuant to which we issued (i) 2,103,307 shares of common stock, consisting of 1,427,000 shares of voting common stock and 676,307 shares of non-voting common stock, (ii) pre-funded warrants (the 2025 Pre-Funded Warrants) to purchase up to an aggregate of 1,922,511 shares of voting common stock, and (iii) accompanying common warrants (the 2025 Common Warrants and, together with the 2025 Pre-Funded Warrants, the 2025 Warrants) to purchase up to an aggregate of 2,012,909 shares of voting common stock. Each Warrant is exercisable for one share of common stock (the 2025 Private Placement). We received gross proceeds of approximately $105.0 million. In connection to the 2025 Private Placement, we also entered into a registration rights agreement with the Purchasers, pursuant to which we agreed to register for resale the shares of common stock sold to the Purchasers, as well as the shares of common stock underlying the 2025 Warrants sold to the Purchasers, on the terms set forth therein. We also entered into a registration rights agreement with Baker Brothers Life Sciences, L.P. (together with its affiliates, the Lead Investor), pursuant to which we agreed to file a resale registration statement with the SEC following demand by the Lead Investor to register the resale of shares of common stock and any common stock issued or issuable upon the exercise or conversion of non-voting common stock and any of our other securities held by the Lead Investor.

As of December 31, 2025, we had cash, cash equivalents and investments of $77.8 million. As of December 31, 2025, we had an accumulated deficit of $642.2 million. Substantially all of our net losses have resulted from costs incurred in connection with our research and development programs and from general and administrative costs associated with our operations. We expect to continue to incur significant expenses and increasing operating losses over at least the next several years. Our net operating losses may fluctuate from quarter to quarter and year to year depending primarily on the timing of our clinical trials and nonclinical studies and our other research and development expenses. We have no internal manufacturing capabilities or sales force and outsource a substantial portion of our clinical trial work to third parties.

Going concern

As of December 31, 2025 and December 31, 2024, we had an accumulated deficit of $642.2 million and $618.0 million, respectively, and cash, cash equivalents and short-term investments of $77.8 million and $56.9 million, respectively. Our current operating plan and projected cash outflows for the upcoming periods raise doubt about our ability to continue as a going concern for at least 12 months from the issuance of the financial statements included elsewhere in this Annual Report. We plan to raise additional capital to fund continued operations beyond the third quarter of 2026. We are taking steps to identify access to future capital and expect to be able to access capital in the future. However, there can be no assurance that any additional funding will be available to us on acceptable terms, if at all. If events or circumstances occur such that we do not obtain additional funding, it may be necessary to significantly reduce the scope of operations to reduce the current rate of spending, which could include reductions in staff and the need to delay, limit, reduce or terminate current or future product development, which could have a material adverse effect on our business, results of operations and financial condition. Moreover, even if financing efforts are successful and additional capital is obtained, available liquidity may still be insufficient to eliminate the aforementioned substantial doubt regarding our ability to continue as a going concern. Accordingly, the report from our independent registered public accounting firm for the year ended December 31, 2025 includes an explanatory paragraph stating that our recurring losses since inception raise substantial doubt about our ability to continue as a going concern. See Part I, Item 1A. Risk Factors under the header “Risks related to our limited operating history, financial position and need for additional capital” for additional information.

Capital resources

Our primary use of cash is to fund operating expenses, which consist primarily of research and development costs related to our drug candidates and our discovery programs, and to a lesser extent, general and administrative expenditures. Our current operating plan and projected cash outflows for the upcoming periods raise doubt about our ability to continue as a going concern for at least 12 months from the issuance of the financial statements. We expect our expenses to increase substantially in connection with our ongoing clinical development activities related to our

chronic hepatitis B drug candidate pevifoscorvir sodium, which has an ongoing Phase 2 clinical trial, as well as our research and development of our other drug candidates within our MASH and coronavirus programs.

We expect that our expenses will increase substantially to the extent we:

We expect that our existing cash, cash equivalents and short-term investments will enable us to fund our operations into the third quarter of 2026, which is less than 12 months following the date of this report. Accordingly, our ability to continue as a going concern will require us to obtain additional funding for our operations or significantly curtail our operations to conserve our capital resources. Moreover, it is particularly difficult to estimate with certainty our future expenses given the dynamic nature of our business, and the macro-economic environment generally.

Because of the numerous risks and uncertainties associated with our research and development programs and because the extent to which we may enter into collaborations with third parties for development of our drug candidates is unknown, we are unable to estimate the timing and amounts of increased capital outlays and operating expenses associated with completing the research and development of our drug candidates. Our future capital requirements will depend on many factors, including:

Developing pharmaceutical products, including conducting nonclinical studies and clinical trials, is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain marketing approval for any drug candidates or generate revenue from the sale of any drug candidate for which we may obtain marketing approval. In addition, our drug candidates, if approved, may not achieve commercial success. Our commercial product revenues, if any, will be derived from sales of drugs that we do not expect to be commercially available for many years, if ever. Accordingly, we will need to obtain substantial additional funds to achieve our business objectives.

Adequate additional funds may not be available to us on acceptable terms, or at all. We do not currently have any committed external source of funds. To the extent that we raise additional capital through the sale of equity or convertible debt securities, ownership interest may be diluted, and the terms of these securities may include liquidation or other preferences and anti-dilution protections that could adversely affect the rights of a common stockholder. Additional debt or preferred equity financing, if available, may involve agreements that include restrictive covenants that may limit our ability to take specific actions, such as incurring debt, making capital expenditures or declaring dividends, which could adversely constrain our ability to conduct our business, and may require the issuance of warrants, which could potentially dilute ownership interest.

If we raise additional funds through collaborations, strategic alliances or licensing arrangements with third parties, we may have to relinquish valuable rights to our technology, future revenue streams, research programs, or drug candidates or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings or collaborations, strategic alliances or licensing arrangements with third parties when needed, we may be required to delay, limit, reduce and/or terminate our product development programs or any future commercialization efforts or grant rights to develop and market drug candidates that we would otherwise prefer to develop and market ourselves.

Cash Flows

The following table summarizes our sources and uses of cash for each of the periods presented (in thousands):

Operating activities

During Fiscal 2025, operating activities used $82.5 million of cash, primarily resulting from our net loss of $24.2 million, which was largely due to ongoing research and development activities and general and administrative expenses to support those activities. Cash used as a result of changes in our operating assets and liabilities of $3.8 million consisted of a decrease of $3.1 million in operating lease liabilities, a decrease of $0.2 million in deferred revenue, a decrease in accrued liabilities of $2.0 million, offset by an increase of $1.4 million in accounts payable and an increase of $0.1 million in other assets. Additionally, there were non-cash charges of $54.5 million, primarily driven by the non-cash change in fair value of the 2023 Common Warrants.

During Fiscal 2024, operating activities used $80.7 million of cash, primarily resulting from our net loss of $131.2 million, which was largely due to ongoing research and development activities and general and administrative expenses to support those activities. Cash used as a result of changes in our operating assets and liabilities of $5.0 million, consisted of a decrease of $2.7 million in operating lease liabilities, a decrease of $1.2

million in deferred revenue, a decrease in accrued liabilities of $1.4 million, partially offset by an increase in other current assets of $0.2 million, and an increase of $0.1 million in accounts payable. Offsetting this, there were non-cash charges of $55.4 million, primarily driven by the non-cash change in fair value of the 2023 Common Warrants.

Investing activities

During Fiscal 2025, investing activities used $37.8 million of cash, consisting primarily of investment purchases of $164.9 million partially offset by investment maturities of $127.5 million.

During Fiscal 2024, investing activities used $18.3 million of cash, consisting primarily of investment purchases of $108.1 million partially offset by investment maturities of $90.0 million.

Financing activities

During Fiscal 2025, net cash provided by financing activities was $101.6 million, primarily from proceeds from issuance of common stock, common warrants and pre-funded warrants in connection with PIPE offering.

During Fiscal 2024, net cash provided by financing activities was not material.

Contractual obligations and commitments

Our principal commitments consist of obligations under license agreements, for example with Emory and KU Leuven, where we may be required to make significant milestone or royalty payments. Additionally we have additional obligations under our operating leases for office space in South San Francisco, California, Belgium, and Shanghai, China and finance lease commitments representing obligations related to vehicle leases for employees and a lease for lab equipment. All of our finance leases are for assets in Belgium. We do not have any material purchase commitments for contracts with fixed or minimum service requirements. We also enter into contracts in the normal course of business with various vendors that generally provide for contract termination following a certain notice period. The Company enters into contracts in the normal course of business that includes arrangements with clinical research organizations, vendors for preclinical research and vendors for manufacturing. These agreements generally allow for cancellation with notice. As of December 31, 2025, we had no material non-cancellable purchase commitments.

Off-balance sheet arrangements

We did not have during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined in the rules and regulations of the SEC.

Indemnification agreements

We enter into standard indemnification arrangements in the ordinary course of business. Pursuant to these arrangements, we indemnify, hold harmless and agree to reimburse the indemnified parties for losses suffered or incurred by the indemnified party, in connection with any trade secret, copyright, patent or other intellectual property infringement claim by any third party with respect to its technology. The term of these indemnification agreements is generally perpetual any time after the execution of the agreement. The maximum potential amount of future payments we could be required to make under these arrangements is not determinable. We have never incurred costs to defend lawsuits or settle claims related to these indemnification agreements. As a result, we believe the fair value of these agreements is minimal.

Critical accounting estimates

Our management’s discussion and analysis of our financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). The preparation of these consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts and the disclosure of assets and liabilities at the date of the consolidated financial statements, as well as the reported expenses incurred during the reporting periods. Our estimates are based on relevant assumptions that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.

While our significant accounting policies are described in the notes to our consolidated financial statements included elsewhere in this Annual Report on Form 10-K, we believe that the following critical accounting policies

are most important to understanding and evaluating our reported financial results and future performance, as these policies relate to the more significant areas involving management’s judgments and estimates.

Accrued research and development expenses

We record accrued expenses for estimated costs of our research and development activities conducted by third-party service providers, which include the conduct of clinical trials and nonclinical studies. We record the estimated expenses of research and development activities based upon the estimated amount of services provided but not yet invoiced. We record accrued expenses for these costs based on factors such as estimates of the work completed and in accordance with agreements established with these third-party service providers and discussions with internal personnel and external service providers as to the progress or stage of completion of these services. Any payments made in advance of services provided are recorded as prepaid expenses and other assets, which are expensed as the contracted services are performed.

As actual costs become known, we adjust our accrued estimates. Although we do not expect our estimates to be materially different from amounts actually incurred, our understanding of the status and timing of services performed could vary from actuals and result in us reporting amounts that are too high or too low in any particular period. Our accrued expenses are dependent, in part, upon the receipt of timely and accurate reporting from clinical research organizations and other third-party service providers. For the periods presented, we have experienced no material differences between our accrued expenses and actual expenses.

Emerging growth company status

In April 2012, the Jumpstart Our Business Startups Act of 2012 (the JOBS Act), was enacted. Section 107 of the JOBS Act provides that an “emerging growth company” (an EGC) can take advantage of the extended transition period provided in Section 7(a)(2)(B) of the Securities Act for complying with new or revised accounting standards. Thus, an EGC can delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. We elected to use the extended transition period for any new or revised accounting standards during the period in which we remained an EGC. Our status as an EGC ended on the last day of the fiscal year ending after the fifth anniversary of our initial public offering, i.e., December 31, 2025.

Recently issued and adopted accounting pronouncements

A description of recently issued accounting pronouncements that may potentially impact our financial position and results of operations is disclosed in Note 2 to our consolidated financial statements.