Cap-dependent Endonuclease Inhibitor S-033188 for the Treatment of Influenza: Results from a Phase 3, Randomized, Double-Blind, Placebo- and Active-Controlled Study in Otherwise Healthy Adolescents and Adults with Seasonal Influenza

Background Cap-dependent endonuclease (CEN) resides in the PA subunit of influenza virus polymerase and mediates the “cap-snatching” process during viral mRNA biosynthesis. S-033188 is a potent, selective, small molecule inhibitor of CEN. Here we report clinical and virologic outcomes from a global Phase 3 study CAPSTONE-1.