Federal regulators approved Hibsago injection on October 20, 2026, marking the first clearance for an antisense oligonucleotide treatment for chronic hepatitis B. Developed by GSK, the new medicine allows certain adult patients without cirrhosis to attempt stopping traditional antiviral tablets under specific clinical supervision.
A regulatory decision announced on October 20, 2026, by the U.S. Food and Drug Administration introduces a distinct therapeutic approach for managing the persistent liver infection that can lead to serious liver disease, including cirrhosis and an increased risk of liver cancer. Living with chronic hepatitis B often means taking lifelong antiviral tablets to keep the virus suppressed without ever clearing it entirely as the virus can stay inside liver cells.
The approval for Hibsago followed priority review and Breakthrough Therapy Designation.
The newly approved medication, Hibsago (bepirovirsen), is administered as a weekly injection under the skin alongside existing antiviral therapy. It functions as a first-in-class antisense oligonucleotide designed to target the genetic instructions the virus uses to replicate and build viral proteins. By interrupting these instructions, the treatment lowers circulating virus and surface antigen levels in the body.
Evaluating Patient Eligibility And Clinical Trial Results For Hibsago
Participants received the subcutaneous injections for up to 24 weeks while maintaining their usual antiviral medication. Afterward, eligible individuals continued their baseline tablets for at least 24 weeks before attempting to stop all treatment if they met strict health and laboratory standards.
Across the clinical evaluations, 24% of patients who received Hibsago met the requirements to stop their existing medicine, compared with zero participants in the placebo group. Twenty-four weeks after all treatment had ended, 19% of the patients who received Hibsago maintained a functional cure. The virus remained under control and surface antigen levels were undetectable in their blood.
🚨#FDA Approval Update | A new approach to chronic hepatitis B treatmentThe FDA has approved #Hibsago (#bepirovirsen), the first antisense oligonucleotide approved for chronic hepatitis B virus (HBV) infection.🔸Used alongside existing antiviral therapy, Hibsago targets HBV… pic.twitter.com/s4DXWsfKqq
In the specific trial breakdowns, the B-Well 1 trial recorded 20% of participants, or 127 of 650 patients, achieving this outcome compared to 0 of 328 patients in its placebo group. The B-Well 2 trial recorded 19% of participants, or 106 of 570 patients, reaching the functional cure milestone compared to 0 of 286 patients in its comparator arm. Combined across both trials, 233 out of 1,220 patients who received bepirovirsen reached a functional cure. Exploratory findings at week 72 demonstrated that 49% of participants overall successfully lowered their surface antigen levels to no more than 100 IU/mL.
Participants whose baseline antigen levels did not exceed 1,000 IU/mL achieved a functional cure rate of 26%, or 200 out of 768 individuals, a group that represents approximately 45% of cases worldwide. Independent European research on patient cohorts noted that about 25% of individuals lost surface antigen by 18 months. Other evaluations showed functional cure rates of 19% at three years, 20% at four years, and 39% at five years.
For many people living with chronic hepatitis B, treatment can mean taking antiviral medication for years to keep the virus suppressed. 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
Treatment eligibility is tightly restricted. Candidates must be adults without cirrhosis who have taken antiviral therapy for at least six months. Candidates must also maintain suppressed viral levels, and present hepatitis B surface antigen levels of 3,000 international units per milliliter or less. To assist clinicians in patient selection and ongoing monitoring, regulators also authorized the Roche Elecsys HBsAg II quant II RxDx assay as a companion diagnostic device. Published academic literature, such as studies cited in the Indian Journal of Gastroenterology and the World Journal of Clinical Cases authored by researchers including S. Swaroop, Shalimar, and S.K. Acharya, highlights that chronic hepatitis B remains a major public health challenge requiring comprehensive vaccination, screening, and expanded access to care.
Liver Risks and Bleeding Require Consistent Medical Supervision
While the therapy offers a path away from daily pills for certain individuals, it carries substantial safety risks. The medication bears a boxed warning for serious liver reactions and low platelet counts, a condition that can elevate the likelihood of potentially life-threatening bleeding.
Patients require consistent medical supervision, which includes regular blood tests before and during treatment to monitor these severe risks. Outside of laboratory abnormalities, reported side effects include injection site reactions, fever, fatigue, and headache.
GSK Plc Secures Approval Through Expedited Pathways
The drug secured approval through expedited pathways, having been granted Breakthrough Therapy and Priority Review designations by the federal agency. GSK plc holds the commercial approval for the treatment.
GSK #GSK $GSK.L secures US FDA priority approval for its chronic hepatitis B treatment Hibsago following Phase III trials. https://t.co/WRiaDlDCmc pic.twitter.com/Z3FPoeR1Ox
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More on Hibsago
The US FDA said on Tuesday it had approved British drugmaker GSK's hepatitis B drug Hibsago, allowing patients with the liver infection a way to keep the virus under control after stopping treatment. https://t.co/1SxnzhpUbT