GSK (LSE:GSK) announced that Japan's Ministry of Health, Labour and Welfare has approved Hibsago (bepirovirsen), an antisense oligonucleotide, as a functional cure for chronic hepatitis B in adults who have completed at least six months of prior nucleos(t)ide analogue therapy and meet specified viral marker thresholds.
The decision marks the first global approval for bepirovirsen and the first functional cure treatment for the disease cleared in Japan, where nearly one million people live with chronic hepatitis B and the condition contributes to roughly 4,000 deaths a year.
The approval was accelerated through Japan's SENKU designation, granted to innovative medicines addressing high unmet medical need.
"After six months of treatment with Hibsago, patients could be freed from life-long therapy and reduce their risk of long-term liver complications", said Tony Wood, GSK's chief scientific officer, calling it a major advance for the company's hepatology portfolio.
Pooled data from the B-Well phase 3 trials showed a 19% functional cure response rate over six months of treatment, against zero in the placebo group, meeting the primary endpoint.
In patients with lower baseline viral antigen levels, representing about 45% of diagnosed cases globally, the cure rate reached 26%.
The most common adverse events were injection site reactions and a temporary rise in a liver enzyme.
GSK is pursuing further regulatory submissions for bepirovirsen in multiple markets, with a decision in the United States expected in the coming months.
News Intelligence what this means for the company
GSK secured the first global regulatory approval for bepirovirsen (Hibsago) as a functional cure for chronic hepatitis B, with Japan's health ministry clearing it under an accelerated SENKU designation. The approval rests on phase 3 data showing a 19% functional cure rate over six months of treatment versus zero in placebo, rising to 26% in the ~45% of patients with lower baseline viral antigen levels; a US PDUFA decision is expected in October 2026, making this the opening move in a multi-market regulatory push for what GSK frames as a major advance in its hepatology portfolio.
This is GSK's first marketed approval for bepirovirsen and validates the antisense oligonucleotide approach to hepatitis B after years of development. The functional cure framing—freeing patients from lifelong nucleos(t)ide analogue therapy after six months of treatment—addresses a genuine unmet need in a disease affecting nearly one million people in Japan alone, though the 19% overall response rate and injection site reactions as the most common adverse event will shape commercial uptake and competitive positioning as the company pursues approvals in other markets.
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