The U.S. Food and Drug Administration approved Hibsago (bepirovirsen) injection on October 20, 2026, as the first FDA-approved antisense oligonucleotide to treat chronic hepatitis B virus infection in certain adults without cirrhosis. The drug is administered under the skin for up to 24 weeks alongside existing antiviral therapy.
For patients living with chronic hepatitis B, standard management traditionally relies on years of continuous antiviral medication to suppress the virus. Hibsago offers an alternative approach by targeting the genetic instructions the virus uses to replicate and produce viral proteins, helping reduce both the viral load and hepatitis B surface antigen levels in the body. The approval covers adults who have maintained suppressed levels of HBV on existing antiviral therapy for at least six months and who have hepatitis B surface antigen levels of 3,000 IU/mL or less, determined through an FDA-authorized test.
For many people living with chronic hepatitis B, treatment can mean taking antiviral medication for years to keep the virus suppressed,
commented Wendy Carter, DO, Acting Director of the Office of Infectious Diseases in the Center for Drug Evaluation and Research. Hibsago provides a new treatment approach that gives some patients the possibility of maintaining control of the virus after all chronic HBV treatment has ended. This approval represents an important advance for people living with this serious disease.
Clinical Trials Evaluate Hibsago Against Placebo
Researchers evaluated Hibsago across two clinical trials comparing the treatment against a placebo. Patients received the injections for up to 24 weeks alongside their current hepatitis B medication, continuing that baseline medicine for at least 24 weeks following their final Hibsago dose. Patients meeting specific health and laboratory requirements were then able to stop their existing medication.
Data detailed the end-of-study results from the B-Well phase 3 trials. Across the trials, 24% of patients receiving bepirovirsen met the requirements to stop their existing medicine, compared with none in the placebo group. Twenty-four weeks after stopping all hepatitis B treatment, 19% of patients who received the drug maintained virus control, and hepatitis B surface antigen remained undetectable in their blood.
Among responders who stopped nucleosidic analogs and completed Week 96, durable functional cure reached 90% in B-Well 1 and 92% in B-Well 2, resulting in a pooled rate of 91%. HBV DNA suppression off all treatment was maintained through Week 96 in 96% of participants whose baseline HBV DNA was below the lower limit of quantification at Week 72.
Post hoc pooled analyses showed that functional cure rates declined as baseline antigen levels increased. Rates at Weeks 72 and 96 were 40% and 35% among participants with baseline antigen levels below 200 IU/mL, compared with 4% among those with levels from 2,500 to 3,000 IU/mL.
Boxed Warning Covers Liver Reactions and Bleeding Risks
Hibsago carries a boxed warning covering serious liver reactions and low platelet counts, which can increase the risk of potentially life-threatening bleeding.
During the durability and follow-up stages between weeks 73 and 96, reported adverse events included upper respiratory tract infection at 4%, decreased creatinine renal clearance at 2%, and nasopharyngitis at 2%. Treatment-related adverse events in that period occurred in 2% of participants and were single events.
Panelists Highlight Implementation Priorities for Care Pathways
Implementation priorities highlighted by the panelists included quantitative HBsAg testing, access to functional cure treatment, patient engagement and adherence tools, provider education, care coordinators, and community awareness. The new 8-step US FC pathway and implementation priorities may help guide the paradigm shift in CHB management from chronic viral suppression to finite FC therapy,
the study’s writers stated.
Alongside the drug approval, the FDA authorized the Roche Elecsys HBsAg II quant II RxDx assay as a companion diagnostic device. This test assists healthcare providers in selecting patients for antiviral therapy under approved drug labeling and in monitoring patient progress throughout the course of treatment.
Earlier coverage: FDA Approves Hibsago to Offer Potential Functional Cure for Hepatitis B