Overview
- The phase III B‑Well 1 and B‑Well 2 trials, published May 29, 2026, reported that weekly bepirovirsen injections produced a functional cure in 19% of treated patients and up to 26% in those with lower baseline HBsAg.
- Functional cure in the studies was defined as undetectable hepatitis B viral DNA and HBsAg for at least six months after stopping all therapy, and no placebo recipients met that standard.
- Bepirovirsen is an antisense drug developed by GSK with Ionis that lowers viral replication and surface antigen while engaging immune control, and most side effects were mild injection‑site reactions and temporary liver enzyme rises.
- The U.S. FDA has placed bepirovirsen in accelerated review with a decision expected in October and regulators in Europe, Japan and China are also assessing the application.
- Key open questions include how long remissions last in broader patient groups not included in the trials—such as people with cirrhosis or high HBsAg—and which baseline markers best predict who will benefit.