R1479

R1479 (4'-azidocytidine) is a nucleoside analog small molecule that acts as a specific inhibitor of the viral RNA-dependent RNA polymerase (RdRp). It was primarily developed by Roche for the treatment of hepatitis C virus (HCV) infection, where it targets the NS5B polymerase with high specificity. R1479 is the active circulating metabolite of the tri-isobutyl ester prodrug balapiravir (R1626). In its active triphosphate form (R1479-TP), it competes with cytidine triphosphate (CTP) for incorporation into the viral RNA strand, acting as a chain terminator. Beyond HCV, R1479 has demonstrated broad-spectrum antiviral activity against other virus families, including flaviviruses (Dengue virus), paramyxoviruses (Nipah and Hendra viruses), and respiratory syncytial virus (RSV). However, clinical development of its prodrug was discontinued due to safety concerns and insufficient efficacy in human trials.

Other names

4'-azidocytidine4'-azido-cytidine