GSK gains first global approval for Bepirovirsen as Japan clears new hepatitis B functional cure
The antisense oligonucleotide (ASO) medicine, which GSK will market in Japan as Hibsago, is approved for adults with hepatitis B who meet specified viral markers.
JAPAN—GSK has secured the world’s first regulatory approval for its chronic hepatitis B treatment bepirovirsen after Japan’s Ministry of Health, Labour and Welfare (MHLW) cleared the therapy, marking the first regulatory entry of a potential functional cure for the disease.
The antisense oligonucleotide (ASO) medicine, which GSK will market in Japan as Hibsago, is approved for adults with hepatitis B who meet specified viral markers.
Eligible patients must also have received at least six months of treatment with a standard-of-care (SoC) viral-suppressing nucleos(t)ide analogue (NA).
Researchers estimate that existing NA treatments produce functional cure rates of only about 1%.
Phase III data support approval
The MHLW based its decision on positive results from the Phase III B-Well programme, in which 19% of patients receiving bepirovirsen for six months achieved a functional cure response, compared with none of those receiving placebo.
Analysts have previously described the results as potentially transformative for the chronic hepatitis B market because they could introduce a new treatment approach for patients who currently require long-term therapy to suppress the virus.
GSK developed bepirovirsen in collaboration with its original developer, Ionis Pharmaceuticals.
The companies are now awaiting regulatory decisions in the United States and Europe as they seek to expand access to the treatment.
The US Food and Drug Administration (FDA) is expected to decide on the medicine in October 2026.
Potential blockbuster opportunity
According to a recent GlobalData report, the anticipated arrival of functional cures could become an important growth driver for the chronic hepatitis B market.
GlobalData forecasts that Hibsago could approach blockbuster status by 2034, generating global sales of US$926 million, while the overall chronic hepatitis B market could reach US$3.2 billion in the same year.
The World Health Organization (WHO) estimates that about 240 million people worldwide live with chronic hepatitis B, including approximately one million people in Japan.
The infection, which spreads primarily through contact with infected bodily fluids, can cause liver inflammation and damage and may lead to serious complications or death if left untreated.
Drugmakers pursue new treatment approaches
NAs have remained the standard treatment for chronic hepatitis B for decades.
However, drugmakers are increasingly developing medicines that target the virus through different mechanisms in an effort to achieve more durable treatment responses.
Gilead Sciences is among the companies pursuing this approach with selgantolimod, which is progressing through late-stage clinical development.
The drug is a toll-like receptor 8 (TLR8) agonist, a mechanism involved in activating the immune response.
GlobalData expects three other pipeline medicines to potentially enter the chronic hepatitis B market before 2034.
These include GSK’s small interfering RNA (siRNA) candidates daplusiran and tomligisiran, Arbutus Biopharma’s hepatitis B virus surface antigen inhibitor imdusiran, and Aligos Therapeutics’ capsid protein inhibitor ALG-000184.
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