Vir Biotechnology Gets FDA IND Clearance and Fast Track for Tobevibart and Elebsiran for Chronic Hepatitis Delta

Vir Biotechnology, Inc. has announced that the FDA has approved its investigational new drug (IND) application and granted Fast Track designation for the combination treatment of tobevibart and elebsiran for chronic hepatitis delta infection. This decision follows promising early results from the Phase 2 SOLSTICE clinical trial, which were presented at the European Association for the Study of the Liver Congress 2024. Tobevibart is an investigational monoclonal antibody, while elebsiran is an investigational small interfering ribonucleic acid (siRNA). Both are currently under evaluation in the SOLSTICE trial, with comprehensive 24-week treatment data expected by the end of the fourth quarter.

Marianne De Backer, the CEO of Vir, emphasized the importance of this development, highlighting the potential of tobevibart and elebsiran to significantly improve treatment options for those suffering from this severe and life-threatening disease. The Fast Track designation from the FDA is critical as it aims to expedite the development and review processes for drugs addressing serious conditions with unmet medical needs.

Chronic hepatitis delta is considered the most severe form of chronic viral hepatitis by the World Health Organization due to its rapid progression to liver cancer and liver-related deaths. Globally, it is estimated that over 12 million people are affected by this condition.

In June, Vir Biotechnology released preliminary data from the Phase 2 SOLSTICE trial, indicating that the treatment with either tobevibart alone or in combination with elebsiran was generally well tolerated. Participants showed high virologic response rates at weeks 12 and 24, sustained response through 48 weeks, and significant ALT normalization rates. The full 24-week treatment data is anticipated in the fourth quarter of the year. The company is also accelerating the initiation of its next study, the ECLIPSE trial. This new trial will be an open-label, randomized, controlled study designed to support potential registration. It will evaluate the safety and efficacy of monthly-administered subcutaneous injections of tobevibart and elebsiran, using the current standard of care as a comparison.

The SOLSTICE trial (NCT05461170) is assessing the safety, tolerability, and efficacy of the combination therapy for chronic hepatitis delta patients. One cohort is focused on the combination therapy dosed every four weeks, while another is evaluating tobevibart monotherapy administered every two weeks. Notably, about half of the participants have compensated cirrhosis.

Tobevibart, also known as VIR-3434, is an investigational antibody formulated for subcutaneous administration. It is designed to block the entry of hepatitis B and delta viruses into liver cells, neutralize the viruses, and reduce viral particles in the blood. Tobevibart has been engineered to have an extended half-life and was identified using Vir’s proprietary monoclonal antibody discovery platform.

Elebsiran, known as VIR-2218, is an investigational siRNA designed to target hepatitis B virus RNA transcripts, thereby limiting the production of hepatitis B surface antigen. This small interfering ribonucleic acid is the first to include Enhanced Stabilization Chemistry Plus (ESC+) technology, which enhances stability and minimizes off-target activity, potentially increasing its therapeutic index. Elebsiran is also the first asset from Vir's collaboration with Alnylam Pharmaceuticals, Inc. to enter clinical trials.

Vir Biotechnology is an immunology company dedicated to harnessing the immune system to treat and prevent infectious diseases and other serious conditions. The company has developed two technology platforms designed to modulate immune responses based on critical observations of natural immune processes. Vir's current clinical pipeline includes candidates targeting hepatitis delta and B viruses, as well as human immunodeficiency virus. The company is also working on preclinical candidates for influenza A and B, COVID-19, RSV/MPV, and HPV.