FUSED TRICYCLIC COMPOUNDS AND USE THEREOF FOR TREATING VIRAL DISEASES

摘要

Fused tricyclic compounds of formula (I) and pharmaceutically acceptable salts thereof are disclosed, wherein X1, X2, X3, X4, Y1, Y2, M1, M2, Ra, Rb, R1, R2 and R6 are as defined in the description. Compositions comprising at least one fused tricyclic compound and methods of using the fused tricyclic compounds for treating or preventing HCV infection in a patient are also disclosed.