ABI-6250

Oct. 29, 2026: Assembly Biosciences (NASDAQ: ASMB) announced dosing of the first two participants in a Phase 2 study of ABI-6250, an investigational oral small-molecule NTCP entry inhibitor, in chronic hepatitis delta virus (HDV) infection.

The multicenter, open-label Phase 2 trial (ABI-6250-201; NCT07762027) is expected to enroll about 80 participants and test two once-daily oral dose levels. Key evaluations include safety, pharmacokinetics, pharmacodynamics, and antiviral activity, including changes from baseline in HDV RNA and alanine aminotransferase. In the main cohort, about 50 participants will receive low- or high-dose ABI-6250 or enter a delayed-treatment group; after the Week 16 primary endpoint analysis, one dose will be selected for a 20-30 participant expansion cohort intended to add safety data for potential Phase 3 development. Initial Phase 2 data are expected in Q4 2027.

The company said completed Phase 1a data in healthy participants supported advancement to Phase 2, with a mean half-life of about four days, once-daily dosing support, and serum bile acid changes consistent with NTCP target engagement.

Under Assembly Bio’s collaboration with Gilead Sciences, Gilead can opt for an exclusive license to ABI-6250 after Phase 2 completion and review of the option data package for a $90 million opt-in fee.