Vir Biotechnology (VIR) H.C. Wainwright 5th Annual Viral Hepatitis Virtual Conference summary

HDV disease background and unmet need

• HDV is a rapidly progressive disease requiring HBV co-infection, leading to cirrhosis or liver cancer within 10 years for most patients.

• No approved HDV therapies exist in the U.S.; bulevirtide is approved in the E.U. but has limited efficacy and high treatment burden.

• Significant unmet need remains for more effective and convenient HDV treatments.

• HDV prevalence may be underestimated due to lack of systematic screening, expected to rise with new therapies.

Therapeutic approaches and clinical development

• Current HBV standard of care is chronic NRTI therapy with little chance for functional cure.

• Novel combination of tobevibart (monoclonal antibody) and elebsiran (siRNA) aims for long-term HDV suppression with less frequent dosing.

• Clinical trials compare this combination to bulevirtide, targeting virologic and ALT normalization endpoints over 48 weeks.

• Fast track designation and accelerated pathways are being pursued for HDV due to orphan status and high unmet need.

Key clinical data and milestones

• SOLSTICE phase 2 interim data showed 55% of patients achieved undetectable HDV RNA at 24 weeks, with significant ALT and surface antigen reductions.

• Full 24-week data and further updates will be presented at upcoming liver conferences, supporting progression to registrational trials.

• HBV program includes the MARCH study, testing doublet and triplet regimens, with end-of-treatment data to be presented soon and functional cure data expected in Q2 next year.

• Decision to advance to phase 3 in HBV will depend on durability of functional cure data.