Vir Biotechnology, Inc. (NASDAQ: VIR) has announced that its investigational drugs, tobevibart and elebsiran, have been granted Breakthrough Therapy designation by the U.S. Food and Drug Administration (FDA) and Priority Medicines (PRIME) designation by the European Medicines Agency (EMA) for the treatment of chronic hepatitis delta (CHD). These designations aim to accelerate the development and review of therapies for serious conditions with unmet medical needs.
SOLSTICE Trial Results
The FDA and EMA designations are supported by data from the Phase 2 SOLSTICE trial, which evaluated the safety, tolerability, and efficacy of tobevibart, alone or in combination with elebsiran, in patients with chronic hepatitis delta. The trial is a multi-center, open-label, randomized study. The company recently presented new data at AASLD The Liver Meeting in San Diego, U.S.
The Phase 2 SOLSTICE trial data indicated that tobevibart and elebsiran could suppress the hepatitis delta virus to undetectable levels. Mark Eisner, M.D., M.P.H., Executive Vice President and Chief Medical Officer at Vir Biotechnology, stated that the designations recognize the potential of this combination to transform the lives of people living with CHD.
Upcoming Phase 3 Program
Vir Biotechnology plans to initiate the Phase 3 ECLIPSE registrational program in the first half of 2025. The ECLIPSE program will include two Phase 3 trials and a Phase 2 study to test the tobevibart-elebsiran combination in different groups of people with chronic hepatitis D. Results from the Phase 3 studies, should they be positive, will be used to support regulatory applications seeking the combo’s approval.
About Chronic Hepatitis Delta
CHD, caused by the hepatitis delta virus, is the most severe form of chronic viral hepatitis and significantly increases the risk of liver cancer, cirrhosis, and liver failure. There is no approved treatment in the U.S., and options are limited in the European Union and globally.
Mechanism of Action
Tobevibart is a broadly neutralizing monoclonal antibody targeting the hepatitis B surface antigen, designed to inhibit the entry of hepatitis B and hepatitis delta viruses into hepatocytes and to reduce the level of circulating viral particles. Elebsiran, a small interfering ribonucleic acid (siRNA), is intended to degrade hepatitis B virus RNA transcripts, potentially exhibiting direct antiviral activity against both hepatitis B and hepatitis delta viruses.
Regulatory Designations
The FDA's Breakthrough Therapy designation facilitates the expedited development and review of drugs that show significant promise in preliminary clinical evidence, potentially offering improvements over existing therapies. The EMA's PRIME designation is awarded to drugs that may significantly benefit patients with unmet medical needs, ensuring early engagement with the EMA to support robust data collection and faster evaluations.
