Ionis Pharmaceuticals: FDA approves HIBSAGO for chronic hepatitis B

What happened
On Oct 20, 2026, Ionis Pharmaceuticals reported that its partner, GSK, announced that the U.S. Food and Drug Administration approved HIBSAGO™ (bepirovirsen) for the treatment of chronic hepatitis B virus infection in combination with nucleos(t)ide analogue reverse transcriptase inhibitor (NrtI) therapy in adult patients without cirrhosis, receiving NrtI therapy for at least 6 months, who have suppressed HBV DNA and with HBsAg levels ≤3000 IU/ml, as determined by an FDA-authorized test. A copy of the press release was furnished as Exhibit 99.1 to the Form 8-K.

Key details

• Approval granted under FDA priority review and Breakthrough Therapy Designation.
• Phase 3 B-Well trials showed functional cure rates of 19% in adults with ≤3000 IU/ml HBsAg versus typically less than 1% with current standard of care after one year.
• Quantitative HBsAg testing will support identification of patients with baseline HBsAg ≤3000 IU/ml; several tests are available, including a recently authorized FDA test.
• GSK licensed bepirovirsen from Ionis in 2019; Ionis has received an upfront payment, license fee and development and regulatory milestone payments and is eligible for additional regulatory and sales milestone payments and tiered royalties of 10-12% on net sales.

Why it may matter
This report was filed as Item 7.01 (Regulation FD disclosure) and Item 8.01 (other events). Item 7.01 furnished the press release announcing the approval; Item 8.01 described the approval, supporting Phase 3 results, licensing history, commercial terms and included forward-looking statements.

This filing does not show why the insider traded or why the company acted.