Assembly Biosciences ABI-6250 Phase 1a Topline at EASL 2026: First-in-Class Oral HDV Entry Inhibitor — The Small-Molecule Competitor to Gilead's Just-Approved Bulevirtide Peptide
Assembly Biosciences presented topline Phase 1a data on ABI-6250 at EASL 2026 (poster WED-579, Dr. Edward Gane, University of Auckland) — a first-in-class oral hepatitis D virus (HDV) entry inhibitor. The Phase 1a study evaluated safety, pharmacokinetics, and pharmacodynamic activity in healthy participants; the data supports advancing directly into a Phase 2 study by year-end. ABI-6250 is the only oral entry inhibitor in development for chronic HDV. The mechanistic context matters: Gilead's Hepcludex (bulevirtide) — a 47-amino-acid injectable lipopeptide NTCP entry inhibitor — just won FDA accelerated approval May 22 as the first US HDV treatment. ABI-6250 targets the same entry-inhibition step but as an oral small molecule rather than an injectable peptide, positioning it as a potential next-generation convenience competitor in the small but newly-validated HDV market. Assembly also announced May 22 an expansion of ABI-6250 development into cholestatic liver diseases. The peptide-vs-small-molecule dynamic in HDV mirrors the same competition that played out in GLP-1 (injectable semaglutide vs oral orforglipron).