Bepirovirsen Approval Offers New Option for Chronic HBV Treatment

The FDA approved bepirovirsen (Hibsago; GSK) injection in combination with existing antiviral therapy to treat a subset of patients with chronic hepatitis B virus (HBV) infection without cirrhosis, making it the first antisense oligonucleotide approved for this indication, the agency announced October 20, 2026.¹

Bepirovirsen is specifically approved for patients without cirrhosis who have received HBV antiviral therapy for at least 6 months, have suppressed HBV levels in their blood, and have hepatitis B surface antigen (HBsAg) levels of 3000 IU/mL or less. The treatment targets the genetic instructions HBV uses to replicate and produce viral proteins, helping reduce the amount of virus and HBsAg in the body.

The FDA also authorized the Roche Elecsys HBsAg II quant II RxDx assay as a companion diagnostic device to help identify patients with chronic HBV infection who are eligible for treatment in accordance with the drug’s FDA-approved labeling and to support monitoring throughout treatment.

“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,” Wendy Carter, DO, acting director of the Office of Infectious Diseases in the Center for Drug Evaluation and Research, said in a news release. “This approval represents an important advance for people living with this serious disease.”

Phase 3 Trials Show Functional Cure in a Subgroup of Patients

Results from the B-Well 1 (NCT05630807) and B-Well 2 (NCT05630820) phase 3 trials supported the FDA’s decision.² Pooled data showed that 6 months of treatment with bepirovirsen achieved a functional cure rate of 19% (233 of 1220 participants vs 0 of 614 in the placebo group). Both trials met their primary end points, demonstrating statistically significant improvements in functional cure vs placebo in the overall study population of adults with HBsAg levels of 3000 IU/mL or less.

In addition, participants with HBsAg levels of 1000 IU/mL or less, a group representing approximately 45% of diagnosed chronic hepatitis B cases globally, achieved a functional cure rate of 26% (200 of 768 participants vs 0 of 393 in the placebo group).

At week 72, exploratory analyses showed that bepirovirsen reduced HBsAg levels to 100 IU/mL or less in 49% of participants (598 of 1220) in the overall study population and in 62% of bepirovirsen recipients in the subgroup of those with HBsAg levels of 1000 IU/mL or less (476 of 768).

Safety and Tolerability Findings

The B-Well 1 and B-Well 2 trials demonstrated an acceptable safety and tolerability profile consistent with previous studies of bepirovirsen. The most common adverse events reported in the trials included injection site erythema, local pain, and a temporary increase in blood levels of a liver enzyme.

Bepirovirsen has a boxed warning for serious liver reactions and low platelet counts, which can increase the risk of potentially life-threatening bleeding.¹ It also carries warnings for worsening kidney function, serious inflammatory adverse reactions, and serious risks associated with improper injection administration. Patients require regular blood tests and follow-up with their health care providers before and during treatment to monitor these risks.

Despite these risks, Mark Makhinson, PharmD, senior director of outpatient and specialty pharmacy at Mount Sinai Health System, emphasized the treatment’s potential in a recent interview with The American Journal of Managed Care^® (AJMC^®).

“I think this is a revolutionary drug that’s going to change the paradigm of care for patients [with HBV],” he told AJMC. “This is the first cure in the space instead of a lifelong treatment. So, taking patients off continuous antiviral therapy and shifting them to a cure-based treatment is really going to impact the paradigm of care. I think patients with a low viral load are going to benefit most from this treatment…I’m hopeful that we see a functional cure in a large proportion of patients in this population.”

References

1. FDA approves first-of-its-kind chronic hepatitis B treatment. News release. FDA. October 20, 2026. Accessed October 21, 2026. https://www.fda.gov/news-events/press-announcements/fda-approves-first-its-kind-chronic-hepatitis-b-treatment
2. Hibsago (bepirovirsen) approved in the US for the treatment of chronic hepatitis B (CHB). News release. GSK. October 20, 2026. Accessed October 21, 2026. https://us.gsk.com/en-us/media/press-releases/hibsago-bepirovirsen-approved-in-the-us-for-the-treatment-of-chronic-hepatitis-b-chb/