Vir Biotechnology’s combination of elebsiran and tobevibart hit its Phase 3 primary endpoint in chronic hepatitis delta with a 44% rate of undetectable virus plus ALT normalization at Week 48, against 0% in the delayed-treatment arm, a gap that cleared statistical significance at p<0.0001. The key secondary endpoint went further: 79% of patients on the combination achieved undetectable HDV RNA at Week 48. Those numbers come from ECLIPSE 1, a 124-patient randomized trial disclosed at the AASLD Liver Meeting in Denver on November 8, 2026.
The trial enrolled patients with advanced disease across multiple countries, and the virologic suppression held across cirrhosis status: 85% of cirrhotic patients (n=46) reached undetectable HDV RNA, compared with 73% of non-cirrhotic patients (n=37). Every patient in the active arm achieved either undetectable virus or at least a 2 log10 RNA reduction by Week 48, a 100% virologic response rate on that broader measure. The only Grade 3 treatment-related adverse event was a neutrophil count decrease that resolved in 15 days, with no treatment interruptions or discontinuations. Bulevirtide (Hepcludex) has received regulatory approval for chronic HDV in certain markets, so the elebsiran-tobevibart combination enters a market that now has a reference standard to beat on both efficacy and tolerability., so the elebsiran-tobevibart combination enters a market that now has a reference standard to beat on both efficacy and tolerability.
The Phase 2 SOLSTICE data, also presented at AASLD, add durability context. All 28 patients who completed 96 weeks of combination therapy reached undetectable viremia, and 89% of those with paired measurements showed improved or stable liver stiffness, a noninvasive proxy for inflammation and fibrosis. That liver-health signal matters because HDV’s clinical burden runs well beyond viral load: cirrhosis progression and liver-related mortality are the outcomes that regulators and payers will want addressed in longer follow-up or confirmatory endpoints.
The practical question now is what regulatory pathway Vir pursues and how the ECLIPSE 1 package compares against bulevirtide’s label. ECLIPSE 1’s monthly subcutaneous dosing and its inclusion of patients with advanced disease give the combination a differentiated profile on paper, but the confirmatory trial design and the durability of response after treatment cessation will determine whether that profile translates into a competitive label. Watch the Week 48 sustained virologic response data off-treatment, which ECLIPSE 1 has not yet reported.
Source link: https://www.sec.gov/Archives/edgar/data/1706431/000162828026071908/vir-20261108.htm
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
