GSK wins US hepatitis B approval, opening a royalty stream for Ionis

The FDA has approved GSK ($GSK)’s Hibsago, or bepirovirsen, alongside nucleos(t)ide analogue treatment for a defined group of adults with chronic hepatitis B without cirrhosis. Eligibility includes at least six months of prior analogue therapy, suppressed viral DNA and a hepatitis B surface-antigen level no higher than 3,000 IU/ml, measured with an authorized test. The new treatment is given as a six-month course.

In the pivotal B-Well studies, 19% achieved functional cure, defined by sustained undetectable viral DNA and surface antigen at least 24 weeks after all treatment stopped. That does not imply universal eradication, and hepatic flares require monitoring. Ionis ($IONS), which discovered and licensed the medicine, is entitled to tiered royalties of 10–12% of net sales and additional contingent milestones; its exposure is through the licensing partnership.

Sources:

• GSK — approval announcement
• GSK issuer release — timestamped reproduction
• Ionis — partner announcement