Assembly Biosciences reports results from Phase 1b trial of ABI-4334

Assembly Biosciences (ASMB) announced positive topline efficacy, safety and pharmacokinetic results from a Phase 1b study evaluating ABI-4334 in participants with chronic hepatitis B virus infection. In the cohort evaluating a 400 mg oral daily dose, potent antiviral activity was observed over the 28-day treatment period similar to that previously reported for the 150 mg dose cohort. The relationship between ABI-4334’s observed antiviral activity and its exposure profile was consistent with having reached full engagement of the first mechanism of action for CAMs, inhibition of viral replication, at the lower 150 mg dose. Safety and PK data from the 400 mg cohort continue to support a once-daily oral dosing profile, while reaching exposure levels at greater multiples of the target exposure anticipated to fully engage a second mechanism of action of CAMs, inhibition of formation of the viral reservoir, cccDNA. Under the collaboration agreement between Assembly Bio and Gilead Sciences (GILD), Gilead has the right to opt in to an exclusive license for further development and commercialization of ABI-4334 after reviewing the Phase 1b option data package to be delivered by Assembly Bio following completion of this study.