• Trial met all Phase 3 endpoints and regimen is well-tolerated with all patients completing 48 weeks of treatment
• 100% of patients achieved virologic response at Week 24 with 79% of patients reaching undetectable virus (as defined by HDV RNA TND) at Week 48
• Comprehensive regulatory filing package planned for U.S. FDA submission mid-2027
• Conference call to discuss topline ECLIPSE 1 results and expanded SOLSTICE Phase 2 data scheduled for November 9, 2026, at 8:30 a.m. ET / 5:30 a.m. PT

Company Website: https://vir.bio
SAN FRANCISCO -- (Business Wire)

Vir Biotechnology, Inc. (Nasdaq: VIR), today announced positive topline results from the pivotal Phase 3 ECLIPSE 1 trial evaluating monthly subcutaneous administration of elebsiran and tobevibart in adults with chronic hepatitis delta (CHD). Topline results were presented in an oral session at the American Association for the Study of Liver Diseases (AASLD) The Liver Meeting^® 2026, in Denver, Colorado.

“For people living with CHD, the goal is not simply to reduce the amount of virus, but to drive it to levels where it is no longer detectable since ongoing HDV replication drives liver disease progression,” said Nancy Reau, Associate Director of Solid Organ Transplantation and Section Chief of Hepatology at Rush University Medical Center. “The high number of participants who achieved undetectable virus and normalized ALT levels in ECLIPSE 1 shows that the combination regimen of elebsiran and tobevibart could offer a meaningful new treatment option for people living with this serious, progressive disease.”

ECLIPSE 1 Week 48 Topline Data

ECLIPSE 1 enrolled a total of 124 patients, randomized 2:1, to receive monthly subcutaneous elebsiran and tobevibart or delayed treatment, with the delayed treatment group initiating therapy at Week 12. The trial enrolled a broad and diverse CHD population across multiple countries and included patients with advanced disease.

The trial’s primary endpoint was met, with a 44% response rate in patients receiving elebsiran and tobevibart achieving undetectable virus as defined by hepatitis delta virus RNA target not detected (HDV RNA TND) plus alanine aminotransferase (ALT) normalization at Week 48, compared with 0%in the delayed treatment group at Week 12 (p<0.0001).

The trial also met its key secondary endpoint, with a 79% response rate in patients achieving undetectable virus at Week 48 versus 0% in the delayed treatment group. Undetectable virus was observed across patients regardless of cirrhosis status, with HDV RNA TND achieved in 85% of cirrhotic patients (n=46) and 73% of non-cirrhotic patients (n=37). Topline data are summarized in the below table, “Phase 3 Efficacy Endpoints.”

The regimen was well-tolerated with a favorable safety profile. There was one Grade 3 treatment-related adverse event (TRAE; neutrophil count decrease, which resolved in 15 days) and no treatment interruptions or discontinuations. Most TRAEs were mild to moderate and transient. The most common TRAE was flu-like symptoms, which predominantly occurred at first dose with the majority resolved within 24 to 48 hours.

Phase 3 Efficacy Endpoints

“Our ambition in hepatitis delta has always been to fundamentally change what patients can expect from treatment. These compelling ECLIPSE 1 results deliver on the potential for elebsiran’s and tobevibart’s complementary mechanisms to drive the virus to undetectable levels, potentially lowering the risk of progression to cirrhosis, liver cancer and liver-related mortality,” said Marianne De Backer, President and Chief Executive Officer of Vir Biotechnology. “We believe the robust viral suppression combined with the flexibility of monthly at-home or healthcare provider administration has the potential to position elebsiran and tobevibart as the best-in-disease treatment for hepatitis delta.”

The elebsiran and tobevibart regimen is also being evaluated in the ECLIPSE 2 and ECLIPSE 3 pivotal trials with data expected in the first quarter of 2027. Data from all three trials will support a comprehensive global regulatory filing package planned for U.S. FDA submission in mid-2027.

The significant unmet need in CHD and the potential for the combination of elebsiran and tobevibart to provide a differentiated treatment option has been recognized by the U.S. Food and Drug Administration (FDA) with Breakthrough Therapy and Fast Track designations, and by the European Medicines Agency (EMA) with Priority Medicines (PRIME) and orphan drug designations.

In December 2025, Vir Biotechnology entered into an exclusive licensing agreement with Norgine, under which Norgine will be responsible for the commercialization of elebsiran and tobevibart in Europe, Australia and New Zealand, subject to receipt of the necessary marketing authorizations.

Conference Call

Vir Biotechnology will host a conference call to discuss the ECLIPSE 1 topline results and expanded SOLSTICE data at 8:30 a.m. ET / 5:30 a.m. PT on Monday, November 9. A live webcast will be available at https://investors.vir.bio and will be archived for 30 days.

About the ECLIPSE Registrational Program

ECLIPSE is a registrational program to evaluate the safety and efficacy of elebsiran in combination with tobevibart in patients with chronic hepatitis delta (CHD). ECLIPSE includes three randomized, controlled trials designed to evaluate the combination therapy in comparison to delayed treatment or bulevirtide. ECLIPSE 1 (NCT06903338) is a Phase 3 trial evaluating the safety and efficacy of elebsiran in combination with tobevibart compared to delayed treatment in the U.S. or other regions where bulevirtide use is limited. ECLIPSE 2 (NCT07128550) is a Phase 3 trial evaluating the efficacy and safety of switching to elebsiran and tobevibart in people with CHD who have not achieved viral suppression with bulevirtide therapy. ECLIPSE 1 and 2 are designed to provide the registrational efficacy and safety data needed for potential submission to global regulatory agencies. ECLIPSE 3 (NCT07142811) is a pivotal head-to-head trial evaluating combination elebsiran and tobevibart compared with bulevirtide in bulevirtide-naïve patients, and it is designed to provide important supportive data to help establish access and reimbursement in key markets.

About Elebsiran and Tobevibart

Elebsiran and tobevibart are investigational agents being evaluated as a novel combination regimen administered monthly as two separate sequential subcutaneous injections for the treatment of chronic hepatitis delta (CHD). The combination is designed to disrupt the hepatitis delta virus (HDV) life cycle at multiple points by addressing both viral entry and the sustained presence of hepatitis B surface antigen (HBsAg) that enables ongoing HDV replication.

Elebsiran is an investigational hepatitis B virus-targeting small interfering ribonucleic acid (siRNA) licensed from Alnylam Pharmaceuticals, Inc. It is designed to degrade hepatitis B virus RNA transcripts and limit the production of HBsAg.

Tobevibart is an investigational broadly neutralizing monoclonal antibody (mAb) targeting HBsAg. It is designed to inhibit the entry of hepatitis B and hepatitis delta viruses into hepatocytes and to reduce the level of circulating viral and subviral particles in the blood. Tobevibart was identified using Vir Biotechnology’s proprietary mAb discovery platform. The Fc domain has been engineered to increase immune engagement and clearance of HBsAg immune complexes and incorporates Xencor’s Xtend™ technology to extend half-life.

About Chronic Hepatitis Delta (CHD)

CHD is the most severe form of chronic viral hepatitis¹ and was recently classified as carcinogenic by the International Agency for Research on Cancer.² People living with the disease rapidly progress to cirrhosis, liver failure³ and liver-related death.¹ Because ongoing hepatitis delta virus (HDV) replication drives disease progression, achieving undetectable virus, as defined by HDV RNA TND (target not detected), is considered an important virologic marker associated with improved clinical outcomes in CHD.⁴ Individuals with CHD who have detectable HDV RNA are at a higher risk of experiencing any liver-related event, including developing compensated and decompensated cirrhosis, hepatocellular carcinoma, liver transplantation and mortality, compared to patients with undetectable HDV RNA.⁴ There are currently limited approved treatments in the U.S. and globally.

About Vir Biotechnology, Inc.

Vir Biotechnology, Inc. is a clinical-stage biopharmaceutical company focused on powering the immune system to transform lives by discovering and developing medicines for serious infectious diseases and cancer. Its clinical-stage portfolio includes programs for chronic hepatitis delta and multiple PRO-XTEN^® dual-masked T-cell engagers across validated targets in solid tumor indications. Vir Biotechnology also has a preclinical portfolio of programs across a range of oncologic malignancies. Vir Biotechnology routinely posts information that may be important to investors on its website.

Forward-looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “should,” “could,” “may,” “might,” “will,” “plan,” “potential,” “aim,” “expect,” “anticipate,” “promising” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. Forward-looking statements contained in this press release include, but are not limited to, statements regarding: the therapeutic potential of the elebsiran and tobevibart regimen to treat patients living with CHD and lower the risk of progression to cirrhosis, liver cancer and liver-related mortality; Vir Biotechnology’s belief that robust viral suppression combined with the flexibility of monthly at-home or healthcare provider administration has the potential to position the regimen as a best-in-disease treatment; Vir Biotechnology’s clinical development plans and expectations for the elebsiran and tobevibart regimen, including protocols for and enrollment into ongoing and planned clinical trials, target endpoints and data readouts (including from the ECLIPSE 2 and ECLIPSE 3 pivotal trials in the first quarter of 2027), as well as plans for a U.S. FDA regulatory submission in mid-2027; Vir Biotechnology’s strategy and plans; and any assumptions underlying any of the foregoing. Many factors may cause differences between current expectations and actual results, including, without limitation: unexpected safety or efficacy data or results observed during clinical studies or in data readouts, including the occurrence of adverse safety events; risks of unexpected costs, delays or other unexpected hurdles; challenges in accessing manufacturing capacity; clinical site activation rates or clinical enrollment rates that are lower than expected; the timing and outcome of Vir Biotechnology’s planned interactions with regulatory authorities, as well as general difficulties in obtaining any necessary regulatory approvals; successful development and/or commercialization of alternative product candidates by Vir Biotechnology’s competitors, as well as changes in expected or existing competition; geopolitical changes or other external factors; and unexpected litigation or other disputes. In light of these risks and uncertainties, the events or circumstances referred to in the forward-looking statements may not occur. Drug development and commercialization involve a high degree of risk, and only a small number of research and development programs result in commercialization of a product. Results in early-stage clinical studies may not be indicative of full results or results from later stage or larger scale clinical studies and do not ensure regulatory approval. The actual results may vary from the anticipated results, and the variations may be material. You are cautioned not to place undue reliance on any scientific data presented or these forward-looking statements, which are based on Vir Biotechnology’s available information, expectations and assumptions as of the date of this press release. Other factors that may cause Vir Biotechnology’s actual results to differ from those expressed or implied in the forward-looking statements in this press release are discussed in Vir Biotechnology’s filings with the U.S. Securities and Exchange Commission, including the section titled “Risk Factors” contained therein. Except as required by law, Vir Biotechnology assumes no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.

Vir Biotechnology has exclusive rights to the universal PRO-XTEN^® masking platform for oncology and infectious disease. PRO-XTEN^® is a trademark of Amunix Pharmaceuticals, Inc., a Sanofi company.

View source version on businesswire.com: https://www.businesswire.com/news/home/20261108631000/en/

Contacts:

Media Contact
Caren Scannell
Director, Communications
cscannell@vir.bio

Investor Contact
Kiki Patel, PharmD
Head of Investor Relations
kpatel@vir.bio

Source: Vir Biotechnology, Inc.