By Adria Calatayud


BARCELONA--GSK said a drug candidate for hepatitis B delivered a functional cure for nearly one fifth of patients in two late-stage clinical trials, in what the company sees as a breakthrough in the treatment of the disease.

The U.K. drugmaker is looking to speed up the development of the medicines it has in the pipeline under recently appointed Chief Executive Luke Miels, as it braces to offset upcoming patent expirations to hit a long-term revenue target. The company previously estimated its hepatitis B drug, bepirovirsen, could bring in more than 2 billion pounds ($2.69 billion) in annual sales at its peak.

The company on Thursday released full results of two phase 3 studies that showed 19% of chronic hepatitis B patients achieved a functional cure response rate in the overall study population after a six-month bepirovirsen treatment consisting of weekly injections. The drug delivered a functional cure rate of 26% in a smaller group of patients with lower viral activity, it added.

GSK said the drug has potential to redefine the treatment of a disease for which the current standard of care typically requires lifelong therapy and achieves functional cure rates of less than 1%.

Analysts at Jefferies said ahead of GSK's study results that a cure rate of 15% to 20% would represent a major improvement in light of the efficacy of current standard therapies.

The number of drugs that failed in clinical trials over the past decade highlights the difficulty of treating the disease, GSK's vice president and medicines development leader for hepatitis B, Melanie Paff, said in an interview.

"We have finally made the initial breakthrough and we will start to build on that," Paff said. "I expect [bepirovirsen] to become the backbone of other therapies."

Hepatitis B is a serious liver infection, which can lead to liver damage, cancer and death, and has been the object of policy debate in the U.S. A key vaccine panel at the Centers for Disease Control and Prevention last year voted to scrap guidance that all newborns be given a first dose of hepatitis B vaccine, but a federal judge in March blocked enforcement of the change.

GSK filed for regulatory approval for bepirovirsen in the U.S., Japan, China and Europe after it reported initial data from the trials early this year. The U.S. Food and Drug Administration has set an October deadline for its decision.

Bepirovirsen is a so-called antisense oligonucleotide, designed to stop the hepatitis B virus from replicating, reduce the level of an antigen that is made by the virus in the blood, and reinvigorate the immune system, the company said. GSK licensed the drug from Ionis Pharmaceuticals.

The study results were published in the New England Journal of Medicine and presented at a scientific congress in Barcelona.


Write to Adria Calatayud at adria.calatayud@wsj.com


(END) Dow Jones Newswires

05-28-26 1013ET