adafosbuvir (Alios BioPharma)

AL-335 (adafosbuvir) is an orally bioavailable, nucleotide-based prodrug that acts as a pangenotypic inhibitor of the Hepatitis C virus (HCV) nonstructural protein 5B (NS5B) RNA-dependent RNA polymerase. Developed by Alios BioPharma, a subsidiary of Johnson & Johnson, AL-335 is designed to be rapidly absorbed and converted into its active triphosphate metabolite, which functions as a chain terminator during viral RNA synthesis, thereby preventing viral replication. The drug was primarily evaluated in combination regimens with other direct-acting antivirals, such as the NS5A inhibitor odalasvir and the NS3/4A protease inhibitor simeprevir, for the treatment of chronic hepatitis C infection. Despite showing high efficacy in Phase 2a trials, Johnson & Johnson announced the discontinuation of its entire hepatitis C clinical development program, including AL-335, in September 2017, citing the crowded market and the availability of highly effective existing therapies.

Other names

adafosbuvir