AB-729 is a subcutaneously-delivered RNAi therapeutic targeted to hepatocytes that inhibits viral replication and reduces all HBV antigens using our novel covalently conjugated GalNAc delivery technology.  AB-729 is currently being dosed in chronic HBV subjects in a Phase 1a/1b clinical study.   

In this ongoing Phase 1a/1b clinical study, AB-729 led to an approximately 1 log₁₀ mean HBsAg decline at week 12 with a single 60 mg dose.  All subjects responded to therapy with a minimum HBsAg decline of -0.62 log₁₀ and a maximum HBsAg decline of -2.14 log₁₀ at week 12. 

In March 2020, we announced positive preliminary Phase 1a/1b clinical trial results for AB-729, and in May 2020 we announced additional positive single-dose Phase 1a/1b clinical trial results for AB-729.

Arbutus believes that the magnitude and continuous reduction in HBsAg achieved with a single 60 mg dose of AB-729 has the potential to provide an important competitive advantage by allowing us to use a low and well-tolerated dose, as well as less frequent dosing.

AB-729 was generally safe and well tolerated through 12 weeks after a single dose with normal ALTs throughout the follow up period.