New hepatitis B drug offers some patients control without ongoing treatment

Bepirovirsen, a newly approved hepatitis B medicine, helped 19% of patients who received it in two late-stage trials keep the virus controlled for 24 weeks after stopping all hepatitis B treatment. None of those receiving placebo alongside standard antiviral medicines achieved that result.

The US Food and Drug Administration approved the injection, sold as Hibsago, on 20 October. It is for selected adults without cirrhosis, or severe liver scarring, whose virus is already suppressed after at least six months of antiviral therapy. Eligibility also depends on blood levels of a viral protein called hepatitis B surface antigen.

Among patients who achieved treatment-free control, that protein was no longer detectable. This outcome is known as a “functional cure”: control without medication, rather than proof that the virus has been permanently eliminated.

Treatment involves injections for up to 24 weeks alongside existing antiviral medicine. Patients continue their usual medicine for at least another 24 weeks, and only those meeting specific medical and laboratory criteria may then stop it.

The advance comes with important limits. Most participants did not achieve a functional cure, and longer follow-up is needed to establish how long the benefit lasts. Hibsago carries a boxed warning for serious liver reactions and low platelet counts, which can cause life-threatening bleeding. Regular blood tests and medical monitoring are required.