Vir Biotechnology’s investigational combination of elebsiran and tobevibart for chronic hepatitis delta (CHD) has met its primary endpoint in a Phase III trial, while a Phase II trial saw 100% of patients treated with the combination achieve undetectable viral levels.
The topline findings of Phase III ECLIPSE 1 (NCT06903338) were presented during an oral session at the American Association for the Study of Liver Diseases (AASLD) The Liver Meeting 2026 in Denver, Colorado.
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The pivotal study demonstrated that 44% of patients receiving monthly subcutaneous injections of elebsiran and tobevibart attained undetectable virus alongside alanine aminotransferase (ALT) normalisation at week 48.
In comparison, no participants in the delayed treatment group achieved this outcome at week 12.
The trial also achieved its key secondary endpoint, with 79% of treated participants reaching undetectable viral levels at week 48 against 0% in the comparator arm.
Among patients receiving the combo, hepatitis delta virus ribonucleic acid (HDV RNA) target not detected (TND) was noted in 85% of the 46 patients with cirrhosis and 73% of the 37 patients without.
In terms of safety, the investigational combination was well-tolerated.
The trial recorded one Grade 3 treatment-related adverse event (TRAE) involving a transient decrease in neutrophil count that resolved within 15 days, with no therapy interruptions or treatment discontinuations occurring.
Transient flu-like symptoms after the initial dose represented the most frequent adverse reaction.
Vir Biotechnology president and CEO Marianne De Backer said: “Our ambition in hepatitis D 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.
“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 D.”
Vir Biotechnology also reported expanded results from the Phase II SOLSTICE trial (NCT05461170) of elebsiran and tobevibart for CHD, where all 28 patients completing 96 weeks of treatment achieved undetectable viral levels.
In an exploratory cohort of ten individuals who discontinued treatment after maintaining viral suppression for 96 weeks, all 10 achieved sustained viral response at 12 weeks without rebound.
Under a December 2025 licensing deal, Norgine holds commercial rights for the therapies in Australia, Europe, and New Zealand.
