On October 20, 2026, Ionis Pharmaceuticals, Inc. announced that its partner GSK has received FDA approval for HIBSAGO™ (bepirovirsen), a new treatment for chronic hepatitis B (CHB). This approval is a significant development for patients suffering from this condition, as it offers a promising alternative to existing therapies.
HIBSAGO™ has been approved for use in adult patients without cirrhosis who have been receiving nucleos(t)ide analogue reverse transcriptase inhibitor (NrtI) therapy for at least six months. The treatment is indicated for those with suppressed HBV DNA and hepatitis B virus (HBV) surface antigen (HBsAg) levels of 3000 IU/ml or less, as determined by an FDA-authorized test.
This milestone is particularly noteworthy as it reflects Ionis' commitment to advancing RNA-targeted therapies, which have the potential to revolutionize treatment options in the pharmaceutical industry. The approval was granted under the FDA's priority review and Breakthrough Therapy Designation, recognizing the significant improvement that bepirovirsen offers over current standard care.
According to the filing, bepirovirsen is a first-in-class RNA-targeted medicine that has demonstrated unprecedented functional cure rates in clinical trials. The Phase 3 B-Well trials revealed that functional cure rates reached 19% in adults with HBsAg levels of 3000 IU/ml or less, compared to less than 1% with standard care alone after one year of treatment. A functional cure is defined as undetectable HBV DNA and HBsAg for at least 24 weeks after stopping treatment, indicating that the immune system can control the disease without medication.
The approval of HIBSAGO™ is expected to impact approximately 1.7 million people in the U.S. living with chronic hepatitis B, a condition that has historically had limited treatment options. Brett P. Monia, Ph.D., chief executive officer of Ionis, highlighted the importance of this development, stating, "About 1.7 million people in the U.S. are living with chronic hepatitis B, and yet treatment options have been historically limited and the vast majority of people living with the chronic infection require lifetime care without achieving meaningful functional cure." This new treatment could provide a significant improvement in patient outcomes.
As part of the collaboration agreement with GSK, Ionis has received various payments, including an upfront payment, license fees, and milestone payments. Additionally, Ionis is entitled to receive tiered royalties of 10-12% on net sales of bepirovirsen, which could further enhance the company's financial position.
Looking ahead, GSK is advancing regulatory submissions for bepirovirsen in multiple geographies, with key regulatory decisions anticipated in the coming months. This could further expand the reach of this innovative treatment and solidify Ionis' position in the pharmaceutical market.
The filing does not specify what happens next, but the approval of HIBSAGO™ represents a significant step forward in the fight against chronic hepatitis B and showcases the potential of RNA-targeted therapies in transforming patient care.