A new drug called Bepirovirsen holds the promise of new advances in the treatment of hepatitis B. The drug, a promising antisense oligonucleotide, is being developed by GSK (GlaxoSmithKline). Phase III data published in May 2026 showed significant functional cure rates (19% in the overall population, 26% in patients with lower viral activity), which could make Bepirovirsen a potential game-changer.
Bepirovirsen is a ‘triple-action’ drug that destroys viral RNA, reduces the production of hepatitis B surface antigens (HBsAg) and stimulates the immune system to control the virus.
The goal is a functional cure. This occurs when the HBsAg antigen is no longer detectable in the blood at least 24 weeks after the end of treatment, without further medication.
In the B-Well Phase III trials, high rates of functional cure were observed compared to 0% with standard therapies.
In an exploratory analysis, 49% of those treated achieved an HBsAg level of ≤ 100 IU/mL one year after the end of treatment.
The US regulatory authority, the FDA, has granted Bepirovirsen Breakthrough Therapy Designation and initiated a Priority Review.