GSK says its drug for chronic hep B could ‘lead to a functional cure’ — but will it be alone or in combination?
GSK, newly branded and soon-to-be demerged, shared interim results from its Phase II trial on its chronic hepatitis B treatment, one that it says has the “potential to lead to a functional cure.”
At a presentation at the EASL International Liver Congress, GSK shared that in around 450 patients who received its hep B drug bepirovirsen for 24 weeks, just under 30% had hepatitis B surface antigen and viral DNA levels that were too low to detect.
Notably, patients who were taking nucleoside analogs (the current standard of care treatment) alongside bepirovirsen and those who were not had similar outcomes.

To put that into perspective, patients with chronic hepatitis B often have to take nucleoside analogs, which suppress hepatitis B virus (HBV) expression, throughout their lifetime. Alone, nucleoside analogs have a functional cure rate that hovers around 1-5%, and in combination with interferon treatment, that number jumps a little higher.
To be considered a functional cure, the virus has to be stifled enough that the immune system can control it on its own, GSK’s head of development Chris Corsico told Endpoints News.
“If we were able … to — using monotherapy for 24 weeks and then stopping therapy — get anything close to the interferon plus nucleoside/nucleotide standard of care, that would be absolutely a phenomenal result,” Corsico said.
The big question now is durability. And without that data in hand yet, Corsico said he can’t call GSK’s treatment a functional cure, though he said their current numbers were exciting for “the long-term prospects.”
However, Corsico also said he “recognized [there is] a large group of patients who need further therapy.” On that end, GSK is exploring trials to put bepirovirsen in combination with an interferon treatment as well as with its hepatitis B immunotherapy, according to a press release.
Corsico noted that more insight on who the treatment was and wasn’t working for would be coming later. “One of the purposes of this study was to collect a whole bunch of biomarkers to see if we could then start using that data to help us predict who was responding and who was not responding,” he said, adding that GSK wouldn’t have that data until the end of the trial.
Around 1% of patients had treatment-related serious adverse events, and Corsico noted that a few of those cases were related to the injection site.
GSK licensed bepirovirsen from Ionis in 2019. The drug is a single strand of synthetic nucleotides that complement HBV RNA and recruit liver enzymes to destroy it.
Elsewhere in the hepatitis B space, the FDA slapped a clinical hold on Antios’ Phase II trial in May, leading to partner Assembly Biosciences ditching the duo’s hepatitis B collaboration.
GSK’s final study results, which include two other treatment arms with different dosage schedules, will be presented towards the end of the year, Corsico said.