GSK Wins Japan’s First Approval for a Functional Cure for Chronic Hepatitis B

GSK’s antisense oligonucleotide (ASO) therapy Hepsavgo (bepirovirsen) has received Japan’s first approval as a functional cure for chronic hepatitis B.

GSK announced on the 24th (local time) that Japan’s Ministry of Health, Labour and Welfare (MHLW) had approved Hepsavgo as a functional cure for chronic hepatitis B (CHB) virus infection.

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

Hepsavgo is indicated for adults who have received nucleoside analog treatment for at least 6 months and meet prespecified viral markers.

The drug is an ASO 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 and suppresses blood levels of hepatitis B surface antigen (HBsAg), helping the immune system regain control of the disease.

Chronic hepatitis B is a disease in which infection persists long term because the immune system cannot eliminate the virus, affecting more than 240 million people worldwide. Approximately 1.1 million people die from the disease each year, and it is considered one of the leading causes of liver cancer.

In Japan, approximately 1 million people have the disease, and about 4,000 die each year.

Tony Wood, GSK’s chief scientific officer (CSO), said, “After 6 months of treatment with Hepsavgo, patients may be able to move beyond lifelong treatment and reduce their risk of long-term liver complications.”

The Japanese approval was based on results from the phase 3 B-Well clinical trial. In the trial, adults with HBsAg levels of 3000 IU/ml or less achieved a 19% functional cure rate. With the current standard treatment alone, the functional cure rate is only 1% after 1 year of treatment.

A functional cure means that hepatitis B virus DNA and HBsAg remain undetectable for at least 24 weeks after all treatment has been discontinued. Loss of HBsAg is associated with reductions of up to 89% in the risk of liver cancer and 62% in the risk of all-cause mortality.

The Japanese approval was expedited under the SENKU designation, which is granted to innovative medicines addressing high unmet medical needs.

Bepirovirsen has received fast-track review and breakthrough therapy designation from the US Food and Drug Administration (FDA), as well as innovative therapy and priority review designations in China.

GSK said it continues to pursue regulatory approval applications for bepirovirsen in several regions, including the United States, with decisions expected over the coming months.