First Hepatitis B Functional-Cure Drug Approved in the US, Marking a Major Treatment Milestone

Chronic hepatitis B treatment has reached an important milestone. On October 19, 2026, British pharmaceutical company GSK announced that the US Food and Drug Administration (FDA) had approved bepirovirsen, marketed as Hibsago, for certain adults with chronic hepatitis B. The drug was approved in Japan in August 2026 and is regarded as the first approved treatment specifically designed to achieve a functional cure for chronic hepatitis B.

The approval represents a significant development in a field where treatment has traditionally focused on suppressing the virus rather than achieving sustained control after medication is stopped. Existing antiviral drugs, including nucleos(t)ide analogues, can effectively suppress viral replication and reduce the risk of complications such as cirrhosis and liver cancer. However, many patients require long-term treatment, and achieving a sustained response after stopping medication remains challenging.

Bepirovirsen uses antisense oligonucleotide technology to target genetic material associated with the hepatitis B virus, reduce viral protein levels and potentially help the immune system maintain longer-lasting control of the infection. According to GSK’s Phase III B-Well clinical trial results, 19% of eligible participants receiving approximately six months of bepirovirsen alongside standard nucleos(t)ide analogue therapy achieved functional cure, defined as maintaining the required response for at least 24 weeks after all treatment was discontinued. No participants in the pooled control group achieved the primary endpoint. Among participants whose baseline hepatitis B surface antigen levels were no higher than 1,000 IU/mL, the functional-cure rate reached 26%.

The drug is not intended for every person living with hepatitis B. Under the US approval, eligible patients must be adults without cirrhosis who have received nucleos(t)ide analogue therapy for at least six months, have suppressed hepatitis B viral DNA and have hepatitis B surface antigen levels of no more than 3,000 IU/mL. A specialist must determine whether a patient meets the criteria based on laboratory results, medical history and the approved prescribing information.

A functional cure does not mean the virus has been completely eradicated.It generally means that hepatitis B virus DNA and hepatitis B surface antigen remain undetectable in the blood for at least 24 weeks after all treatment has stopped. This indicates sustained control of the infection, but it does not prove that every trace of viral genetic material has been eliminated from liver cells. Nor does it mean that all long-term liver-related risks have disappeared. Continued medical follow-up remains important even for patients who achieve this endpoint.

The US approval has also raised questions about when the drug may become available in China. Public reports indicate that its Chinese marketing application has entered the regulatory review process. The company has previously indicated that approval could come in 2027, although the timeline remains subject to the outcome of the review. Approval in the United States does not mean the drug is already approved or widely available in mainland China.

Overall, bepirovirsen offers a new treatment option for a defined group of people with chronic hepatitis B and represents progress toward the long-standing goal of functional cure. However, the overall trial response rate of 19% underscores that the treatment does not work for everyone and has specific eligibility requirements. Patients should not discontinue existing antiviral medication on their own or make treatment decisions based solely on online reports. They should consult a liver-disease specialist and follow the indications and prescribing guidance approved in their jurisdiction.