By: IPP Bureau
Last updated : August 26, 2026 9:13 am
The emergence of functional-cure approaches could reshape the market, which has historically been dominated by long-term viral suppression
GSK has secured the world's first regulatory approval for bepirovirsen, an antisense oligonucleotide (ASO)-based therapy designed to achieve a functional cure for chronic hepatitis B (HBV), from Japan's Ministry of Health, Labour and Welfare (MHLW).
GSK will market the therapy in Japan under the brand name Hibsago, with the approval covering adults with chronic hepatitis B who meet defined viral markers and have received at least six months of prior treatment with standard-of-care nucleos(t)ide analogue (NA) therapy.
The approval marks a potential shift in the treatment paradigm for chronic hepatitis B, where current NA therapies primarily suppress the virus and are associated with functional cure rates estimated at around 1%.
The Japanese approval was supported by results from the Phase III B-Well programme, in which 19% of patients treated with Hibsago for six months achieved a functional cure response, compared with none in the placebo group.
Bepirovirsen works by targeting hepatitis B viral RNA through an antisense mechanism, with the aim of reducing viral proteins and enabling the immune system to control the infection after treatment.
The therapy was originally developed by Ionis Pharmaceuticals, which partnered with GSK on its development.
GSK and Ionis are now awaiting regulatory decisions in other major markets. The US Food and Drug Administration (FDA) is expected to make a decision on Hibsago in October 2026, while a regulatory review is also under way in Europe.
The approval comes against a backdrop of a significant global burden of chronic hepatitis B. The World Health Organization estimates that around 240 million people worldwide live with chronic hepatitis B, including approximately one million people in Japan.