Bepirovirsen achieves 19% functional cure rate in chronic hepatitis B

On September 18, 2026, GSK announced results from its pivotal phase 3 trials, B-Well 1 and B-Well 2. The data indicated that bepirovirsen, an investigational antisense oligonucleotide, reached a 19% functional cure rate in adults with chronic hepatitis B at week 72 after they stopped treatment. In this context, a functional cure is defined as maintaining undetectable levels of HBV DNA and HBsAg for at least 24 weeks without ongoing therapy. This development addresses a condition that currently affects millions of people worldwide.

The work on bepirovirsen is part of a wider effort to find more effective treatments for chronic hepatitis B, which can lead to serious liver disease. Historically, options for patients have been limited, and many do not see a sustained response to the therapies currently available. These phase 3 trials were designed to evaluate the safety and efficacy of bepirovirsen, specifically looking at its ability to provide a functional cure for those who have long dealt with the infection.

Participants in the B-Well 1 and B-Well 2 trials were monitored closely to track their progress following treatment. Because the trials included a diverse range of adult participants, researchers were able to evaluate how the drug performed across various patient demographics. The findings suggest that bepirovirsen could change the current approach to treating chronic hepatitis B, providing a new path for patients who have had few successful alternatives in the past.

Beyond individual outcomes, the results of the bepirovirsen trials carry implications for public health, particularly in regions where the virus is most common. Reaching a functional cure can help lower the overall burden of liver disease and reduce the long-term costs of healthcare. These findings also point to the role of continued investment in the research and development of antiviral therapies designed to provide durable solutions for chronic infections.

Looking ahead, GSK is preparing for the next stages of the regulatory process. The US FDA has accepted the New Drug Application (NDA) for priority review, with a PDUFA date of October 26, 2026. Bepirovirsen has also been granted a Breakthrough Therapy designation, a status that reflects its potential to improve upon existing treatment standards. If approved, the drug could become a central part of managing chronic hepatitis B, impacting patient outcomes and quality of life.