GSK wins Japan’s first approval for a functional cure for chronic hepatitis B

GSK has received the first global approval in Japan for a treatment targeting a functional cure for chronic hepatitis B (CHB).

GSK announced on the 24th that Japan’s Ministry of Health, Labour and Welfare (MHLW) approved Hibisago, an antisense oligonucleotide (ASO) therapy whose active ingredient is bepirovirsen, as a functional cure for chronic hepatitis B virus infection.

This is the first global approval for bepirovirsen and the first and only CHB functional cure treatment approved in Japan.

Hibisago is indicated for adults who have received nucleoside analog therapy for at least 6 months and meet prespecified viral marker criteria.

The treatment is designed to recognize RNA, a genetic component of the hepatitis B virus, and inhibit its production. It reduces HBV-related RNA and viral protein production, lowers blood levels of hepatitis B surface antigen (HBsAg), and stimulates the immune system to induce a sustained, stable immune response.

Chronic hepatitis B is a disease in which infection persists over the long term because the immune system cannot clear the virus. More than 240 million people worldwide have the disease. It causes about 1.1 million deaths each year and is considered one of the leading causes of liver cancer worldwide.

About 1 million people in Japan have the disease, and about 4,000 die from it each year. The Japanese government has demonstrated a strong commitment to eliminating CHB, including through nationwide screening and treatment programs.

The approval in Japan was based on results from the Phase 3 B-Well clinical trial. In the trial, the functional cure rate among adults with HBsAg levels of 3000IU/ml or lower was 19%. This compares with a functional cure rate of just 1% after 1 year of treatment with current standard therapy alone.

A functional cure is defined as undetectable hepatitis B virus DNA and HBsAg, a viral protein, for at least 24 weeks after all treatment has been stopped. It means the disease is being controlled by the immune system without drug treatment.