Vir Biotechnology (VIR) Study Update summary

Study background and unmet need

• Chronic hepatitis delta is a severe, rapidly progressing liver disease with high mortality and limited treatment options, especially in the US where no approved therapies exist.

• The disease is associated with a high risk of cirrhosis, liver cancer, and significant economic burden.

• The SOLSTICE phase II trial evaluates tobevibart and elebsiran, targeting viral entry and antigen production, aiming for transformative viral suppression.

Study design and patient population

• The trial includes three main cohorts: combination rollover (6 non-cirrhotic), de novo combination (32), and tobevibart monotherapy (33), with both non-cirrhotic and compensated cirrhotic patients.

• Primary endpoints are safety and efficacy (virologic response and ALT normalization at week 24).

• All participants were on hepatitis B therapy prior to enrollment.

Efficacy results

• De novo combination therapy showed rapid and substantial HDV RNA decline, with over 50% achieving undetectable RNA (TND) by week 24.

• ALT normalization rates increased over time, with more than 50% achieving normalization at week 24 in both combination and monotherapy cohorts.

• Tobevibart monotherapy also demonstrated potent antiviral activity, though slightly lower than combination therapy.

• Virologic suppression and ALT normalization were similar in non-cirrhotic and compensated cirrhotic patients in the combination cohort.