FDA Approves Bepirovirsen for Chronic Hepatitis B Functional Cure

Adults living with chronic hepatitis B who lack cirrhosis face a new regulatory standard for antiviral care following the October 20, 2026, approval of bepirovirsen by the US Food and Drug Administration, HCPLive reported.

Key Clinical Takeaways:

• Bepirovirsen received FDA approval on October 20, 2026, as the first treatment of its kind for chronic hepatitis B.
• Patient selection requires quantitative hepatitis B surface antigen testing at or below 3000 IU/mL, supported by an authorized companion diagnostic.
• Clinical trials demonstrated functional cure rates up to 28% in specific baseline subgroups, though monitoring for liver enzyme elevations and thrombocytopenia remains mandatory.

Quantitative HBsAg Testing Mandates New Screening Protocols

Clinicians must now integrate quantitative hepatitis B surface antigen testing into routine evaluations for adult patients. Norah Terrault noted in a companion interview that this specific measurement has not historically been performed on a routine basis. The FDA-approved indication specifies that candidates must have received HBV antiviral therapy for at least six months, maintain suppressed HBV DNA, and exhibit an HBsAg level of 3000 IU/mL or lower. To facilitate this precise selection, the agency authorized the Roche Elecsys HBsAg II quant II RxDx assay as a companion diagnostic.

For individuals not currently undergoing antiviral treatment, clinical pathways involve initiating antiviral therapy first. Providers evaluate patient qualification only after these individuals complete the mandatory minimum six-month antiviral window. Patients who eventually receive bepirovirsen continue their existing antiviral medications for at least 24 weeks after their final injection before stopping treatment, provided they meet specific clinical and laboratory parameters.

Phase III B-Well Trial Data Define Functional Cure Metrics

The studies defined a functional cure as hepatitis B surface antigen loss paired with HBV DNA levels remaining below the lower limit of quantification, sustained for a minimum of 24 weeks following the cessation of all HBV therapy. Results from the B-Well 1 trial showed that 20% of bepirovirsen recipients, or 127 out of 650 patients, achieved this functional cure by week 72. The B-Well 2 trial reported a comparable outcome, with 19% of participants, or 106 of 570 patients, reaching the same endpoint. None of the patients receiving placebos achieved this result.

Subgroup analyses from the trials revealed higher efficacy among specific patient profiles. Among participants with a baseline HBsAg level of 1000 IU/mL or lower, functional cure rates reached 25% in the first trial cohort and 28% in the second.

Safety Monitoring Requirements for Platelets and Liver Enzymes

Safety evaluations from the clinical development program established specific monitoring protocols regarding adverse events. Grade 3 or higher adverse events occurred in 16% of bepirovirsen recipients compared to 3% of patients in the placebo arms. Alanine aminotransferase elevations represented the most frequent adverse event observed during treatment.

The drug carries a boxed warning flagging the risks of serious liver reactions and thrombocytopenia. Terrault discussed these safety requirements, emphasizing the necessity of closely tracking patient platelet counts, liver enzymes, and kidney function throughout the therapeutic course.

Disclaimer: The information provided in this article is for educational and scientific communication purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider regarding any medical condition, diagnosis, or treatment plan.