FDA Approves Bepirovirsen as Potential Functional Cure for Chronic Hepatitis B

The U.S. Food and Drug Administration has granted approval to bepirovirsen, marketed as Hibsago, providing a potential functional cure for adult patients living with chronic hepatitis B who do not have cirrhosis and are currently utilizing antiviral therapy. The regulatory decision marks a significant milestone in the management of the viral infection, which remains a leading contributor to severe liver complications worldwide.

Clinical Trial Findings and Efficacy

Approval of the antisense oligonucleotide medication was supported by data derived from the B-Well 1 and B-Well 2 clinical trials. Results demonstrated that nearly one in five participants who received bepirovirsen alongside background antiviral medications achieved a functional cure at week 72, compared to no patients in the control group receiving a placebo.

Furthermore, trial data showed that efficacy varied according to baseline hepatitis B surface antigen levels:

• Patients with antigen levels of 3,000 IU/mL or less achieved functional cure rates between 19 percent and 20 percent.
• Among individuals with antigen levels of 1,000 IU/mL or less, the functional cure rate increased to 26 percent.

Researchers noted that the drug is administered as a six-month course and can be self-administered by patients following the initial healthcare-provider-administered dose. The therapy is strictly indicated for individuals who have maintained antiviral therapy for at least six months, have suppressed hepatitis B virus blood levels, and meet specific antigen threshold requirements.

Safety Profile and Regulatory Warnings

While the medication offers a new therapeutic approach, regulatory authorities emphasized the necessity of vigilant patient monitoring due to notable safety risks. The approved prescribing information includes a boxed warning highlighting the potential for serious hepatic flares during treatment, as well as low platelet counts that can lead to life-threatening thrombocytopenia.

Additional warnings outlined by the FDA include risks associated with worsening kidney function, serious inflammatory adverse reactions such as vasculitis, and complications stemming from improper injection techniques. Consequently, patients prescribed the medication must undergo regular blood testing throughout the course of treatment. The therapy is also not recommended for individuals with a coinfection of the hepatitis D virus.