GSK has secured U.S. approval for bepirovirsen, an antisense oligonucleotide licensed from Ionis Pharmaceuticals, marking a milestone in the treatment of chronic hepatitis B. Marketed as Hibsago, the medicine introduces an antisense-based approach to the infection and offers patients the possibility of achieving a functional cure with a finite course of treatment.
The FDA approved Hibsago late Tuesday for use alongside nucleos(t)ide analogue reverse transcriptase inhibitor (NrtI) therapy in adults with chronic hepatitis B who do not have cirrhosis. Eligible patients must have received NrtI treatment for at least six months, have suppressed hepatitis B viral DNA and have hepatitis B surface antigen levels of no more than 3,000 IU/mL.
The decision followed an FDA priority review and the medicine’s designation as a breakthrough therapy. GSK argues that the combination could offer an important advantage over existing standard treatments, including Bristol Myers Squibb’s Baraclude and Gilead Sciences’ Viread.
Although nucleos(t)ide analogues help control hepatitis B by suppressing viral replication, they rarely eliminate the need for continued treatment. A functional cure generally refers to sustained suppression of viral activity and surface antigen to very low or undetectable levels, reducing the ongoing burden of infection without necessarily eradicating every trace of the virus.
GSK Chief Scientific Officer Tony Wood said many people with chronic hepatitis B continue to take medication indefinitely despite available treatments, leaving them vulnerable to serious liver complications. He said Hibsago could allow eligible U.S. patients to pursue a functional cure following a six-month treatment course, with self-administration possible after the initial dose.
In its October 20 announcement, the FDA described Hibsago as a first-of-its-kind treatment for chronic hepatitis B. Wendy Carter, acting director of the agency’s Center for Drug Evaluation and Research Office of Infectious Diseases, said the authorization signifies very meaningful progress for people affected by the potentially serious infection.
Jefferies analysts similarly interpreted the approval as validation of the functional-cure approach. However, they cautioned that safety requirements and the need for ongoing monitoring could complicate the medicine’s adoption and make its real-world course harder to predict.
Chronic hepatitis B is a persistent infection that affects the liver and can progress to severe complications, including cirrhosis and liver cancer.
Bepirovirsen works by targeting the viral genetic material involved in producing hepatitis B proteins and supporting viral replication. By reducing the amount of viral DNA and surface antigen, the treatment aims to bring the infection under sufficient control to achieve a functional cure.
GSK obtained rights to bepirovirsen through a licensing agreement with Ionis in 2019. The drug has since become the central focus of GSK’s hepatitis B functional-cure strategy, particularly after the company discontinued development of another candidate last year.
GSK expects Hibsago to become available to U.S. patients before the end of 2026. A company spokesperson said the list price would be announced after discussions with insurers and other payers regarding pricing and reimbursement have concluded.
The spokesperson explained that GSK considers clinical outcomes and the value delivered to patients, healthcare professionals and payers when setting medicine prices, while also taking market conditions and broader societal expectations into account.
What Is GSK’s New Hepatitis B Treatment?
GSK’s Hibsago contains bepirovirsen, an antisense oligonucleotide designed to target the genetic material involved in hepatitis B virus activity. By reducing the production of viral RNA and proteins, the medicine aims to help the body regain control of the infection. GSK developed the treatment in collaboration with Ionis Pharmaceuticals, which licensed the medicine to GSK.
Who Is Eligible for Hibsago?
The FDA approved Hibsago in combination with existing antiviral therapy for certain adults with chronic hepatitis B who do not have cirrhosis. Eligible patients must have received antiviral treatment for at least six months, have suppressed hepatitis B virus DNA, and have hepatitis B surface antigen levels of 3,000 IU/mL or less, as determined by an FDA-authorized test.
