GSK (GSK.US) breakthrough hepatitis B therapy reaches the main end point of phase 3 trial, application for marketing to be submitted soon

The Zhitong Finance App learned that GSK (GSK.US) today announced that its ongoing antisense oligonucleotide (ASO) therapy, bepirovirsen, developed in collaboration with Ionis Pharmaceuticals, has achieved positive results in two key phase 3 clinical trials B-Well 1 and B-Well 2 for the treatment of chronic hepatitis B (HBV). Both trials reached major endpoints. Bepirovirsen showed a statistically and clinically significant functional cure rate. GSK plans to launch a global regulatory filing in the first quarter of 2026.

Chronic hepatitis B is a major global health challenge, affecting more than 250 million people, and is one of the leading causes of liver cancer. Currently, standard treatments based on nucleoside (acid) analogs usually require long-term or even lifelong medication, but their functional cure rate is still low, usually only about 1%.

B-Well 1 and B-Well 2 are global multicenter, randomized, double-blind, placebo-controlled trials to evaluate the efficacy, safety, pharmacokinetic characteristics of bepirovirsen, and the durability of functional cure in chronic hepatitis B patients receiving nucleoside (acid) analogs and baseline HBsAg ≤ 3000 IU/ml. The primary endpoint was the proportion of patients with baseline HBsAg ≤3000 IU/ml achieving functional cure. One key secondary endpoint was the proportion of patients with baseline HBsAg ≤1000 IU/ml achieving functional cure. Functional cure is defined as loss of HBsAg and undetectable HbV DNA for at least 24 weeks after the end of a limited course of treatment.

The analysis showed that the B-Well trial reached the main end point, and bepirovirsen showed a statistically significant and clinically significant functional cure rate. Compared with standard treatment with single use, bepirovirsen combined with standard treatment significantly improved the functional cure rate. Statistically significant was achieved in all endpoints, including patients with baseline HBsAg ≤ 1000 IU/ml, where stronger effects were observed in this population. The tests also showed that bepirovirsen was safe and well tolerated, consistent with previous findings.

Bepirovirsen is an ASO therapy under development with a triple mechanism of action. It aims to identify and destroy the genetic component (i.e. RNA) of the hepatitis B virus, so that the patient's immune system may regain the ability to control viral infections.