SCY-635

SCY-635 is a novel, nonimmunosuppressive analog of cyclosporine developed as an oral antiviral agent. It acts primarily as a cyclophilin inhibitor, targeting the peptidyl prolyl isomerase activity of cyclophilin A (CypA), which is essential for hepatitis C virus (HCV) replication. Unlike traditional cyclosporine, SCY-635 does not significantly inhibit calcineurin phosphatase activity and therefore lacks immunosuppressive effects at therapeutic concentrations. The drug has demonstrated potent suppression of HCV replication in vitro and in vivo by disrupting the interaction between CypA and the viral NS5A protein, thereby blocking viral replication. Additionally, it has shown additive to synergistic antiviral effects when combined with interferon-alpha or ribavirin without increasing cytotoxicity. SCY-635 reached Phase II clinical trials for chronic hepatitis C infection and was also studied preclinically for hepatitis B virus (HBV) infection[1][2][3][4][5][6][7].