AB-423

AB-423 is an orally available, small molecule member of the sulfamoylbenzamide (SBA) class that inhibits hepatitis B virus (HBV) replication by targeting the viral core (capsid) protein[1][3][6][2]. AB-423 acts as a class II HBV capsid inhibitor, blocking pgRNA encapsidation and preventing the formation of covalently closed circular DNA (cccDNA) via inhibition of the capsid uncoating step[1][2][3]. It is selective for HBV, shows potent pan-genotypic activity including against nucleos(t)ide-resistant variants, and demonstrates additive or synergistic effects when combined with other anti-HBV agents such as nucleos(t)ide analogs or RNAi therapies[1][2]. Preclinical and phase 1 studies show significant anti-HBV activity with preferential accumulation in the liver, and a favorable pharmacokinetic and toxicity profile[1][3][6]. AB-423 was developed by Arbutus Biopharma, with origins at the Baruch S. Blumberg Institute and Drexel University College of Medicine[6][2].