Used in research for the treatment of hepatitis C virus (HCV) infection. Acts as a nucleoside inhibitor targeting the viral RNA polymerase, helping to block viral replication. Shows high potency against HCV genotypes and is studied for use in combination therapies to improve cure rates. Also investigated for its metabolic stability and ability to generate active triphosphate forms in liver cells.

PSI-697 is a nucleoside analog that undergoes metabolic activation in the body to its active form, offering high efficacy and low potential for drug resistance compared to other classes. It advanced to clinical trials but was further developed into more effective and safer compounds, such as sofosbuvir, which is now widely used. Although not commercialized, data from PSI-697 studies played a key role in designing next-generation HCV antivirals with high potency and reduced side effects.