The U.S. Food and Drug Administration (FDA) has approved Hibsago (bepirovirsen) injection, in combination with existing antiviral therapy, to treat chronic hepatitis B virus (HBV) infection in certain adults without cirrhosis. Hibsago is the first FDA-approved antisense oligonucleotide for this condition.
The approval is limited to adults without cirrhosis who have been taking HBV antiviral therapy for at least six months, have suppressed levels of HBV in their blood, and have hepatitis B surface antigen (HBsAg) levels of 3,000 IU/mL or less, as determined by an FDA-authorized test.
The FDA also authorized the Roche Elecsys HBsAg II quant II RxDx assay as a companion diagnostic device to aid in patient selection and monitoring for Hibsago.
According to clinical trials, Hibsago is administered as an injection under the skin for up to 24 weeks. Patients continue their existing hepatitis B medicine for at least 24 weeks after their last Hibsago injection. Across the two trials, 24% of patients who received Hibsago met the requirements to stop their existing medicine, compared with none who received placebo. Twenty-four weeks after stopping all hepatitis B treatment, 19% of patients who received Hibsago still had the virus under control, and hepatitis B surface antigen could not be detected in their blood.
Hibsago carries a boxed warning for serious liver reactions and low platelet counts, which can increase the risk of potentially life-threatening bleeding. It also carries warnings for worsening kidney function, serious inflammatory adverse reactions like vasculitis, and serious risks if the injection is not administered properly. The most common side effects, excluding laboratory abnormalities, are injection site reactions, fever, fatigue, and headache.
The FDA granted Hibsago Fast Track and Breakthrough Therapy designations as well as Priority Review. The approval was granted to GSK plc.
