Control of Hepatitis B Virus with Imdusiran, a Small Interfering RNA Therapeutic

Chronic hepatitis B is a global health concern with a high risk of end-stage liver disease. Current standard-of-care agents have low cure rates, and new therapies are needed. Small interfering RNAs (siRNAs) that target viral RNAs fulfill a gap not addressed by standard-of-care agents and may contribute to a functional cure. Here, we describe the preclinical characterization of imdusiran (AB-729), a novel, pan-genotypic siRNA therapeutic that effectively reduces HBsAg, viral antigens, and viral replication in chronic hepatitis B patients and is currently in Phase 2 clinical studies. In hepatitis B virus (HBV) cell-based systems, imdusiran possessed pan-genotypic nanomolar potency and retained activity against HBV target site polymorphisms. Imdusiran was active against nucleos(t)ide analogue- and capsid assembly modulator-resistant HBV isolates, and combination with standard-of-care agents was additive. In an HBV adeno-associated virus mouse model, HBsAg was reduced up to 3.7 log