US regulators have approved a new injectable drug that could allow some patients with chronic hepatitis B to stop taking daily antiviral medication after treatment.

The Food and Drug Administration cleared Hibsago, known chemically as bepirovirsen, for adults managing the chronic liver infection. Developed by GSK in collaboration with Ionis Pharmaceuticals, which licensed the drug to GSK, it is the first antisense oligonucleotide approved by the FDA to treat chronic hepatitis B.

The milestone offers new hope to millions of patients who currently rely on lifelong antiviral therapy.

How Hibsago Achieved a 19% Functional Cure Rate in Clinical Trials

Hibsago targets the genetic instructions the hepatitis B virus uses to make copies of itself and produce viral proteins, helping reduce the amount of virus and hepatitis B surface antigen in the body. In clinical trials, participants received Hibsago injections under the skin alongside their daily antiviral medication for up to 24 weeks, with injections given twice weekly during the first two weeks and once weekly thereafter.

Patients continued taking daily antivirals for at least 24 weeks after their final injection before doctors tested whether they could stop therapy. Across the two trials, 24% of patients receiving Hibsago met the criteria to stop their existing hepatitis B medication, compared with none in the placebo groups.

Twenty-four weeks after stopping all therapy, 19% of Hibsago patients kept the virus suppressed with undetectable surface antigen levels. None of the patients in the placebo group achieved this benchmark.

The results suggest that Hibsago could help some patients achieve sustained viral control without medication, although most trial participants did not meet the criteria for a functional cure.

Who Qualifies for New Hepatitis B Drug Hibsago

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Hibsago is not approved for everyone living with chronic hepatitis B. To qualify, patients must be adults without liver cirrhosis who have taken daily antiviral therapy for at least six months.

Candidates must have suppressed hepatitis B virus DNA levels and hepatitis B surface antigen (HBsAg) levels of 3,000 IU/mL or less, as determined by an FDA-authorised test. The FDA also authorised a Roche companion diagnostic to help identify eligible patients and monitor them during treatment.

'Hibsago provides a new treatment approach that gives some patients the possibility of maintaining control of the virus after all chronic HBV treatment has ended,' said Wendy Carter, DO, acting director of the Office of Infectious Diseases at the FDA's Center for Drug Evaluation and Research.

FDA Boxed Warning for Hibsago: Liver and Bleeding Risks

Federal regulators approved Hibsago with a boxed warning for serious liver reactions and low platelet counts, which can increase the risk of potentially life-threatening bleeding. Patients require regular blood tests and medical follow-up before and during treatment to monitor these risks.

The medication also carries warnings for declining kidney function, blood vessel inflammation, and improper injection technique. The most common side effects, excluding laboratory abnormalities, were injection site reactions, fever, fatigue and headache.

Specialists caution that patients must never stop taking their prescribed hepatitis B medicines on their own. Abruptly quitting standard antiviral pills without medical supervision can cause sudden, catastrophic liver failure.

Hibsago Pricing, UK Access, and Patient Hopes for a Cure

For patients, the possibility of ending lifelong treatment marks an enormous physical and emotional milestone. Rodolfo, an advocate who shared his journey through the Hepatitis B Foundation, viewed standard daily antivirals as an exhausting burden.

'I refused to accept taking medication forever,' Rodolfo said while seeking experimental trials. 'You feel like a prisoner to daily pills that keep the virus asleep but never truly get rid of it.'

Commercial rollout details remain unresolved, as drugmaker GSK has not yet disclosed US wholesale pricing or insurance coverage timelines.

Hibsago is not yet approved in the United Kingdom, with regulatory decisions in Europe and China still pending. UK health data shows that tenofovir and other antiviral medicines remain important treatments for chronic hepatitis B. Hibsago's potential availability in the UK will depend on future regulatory decisions.

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