The present invention relates to Fused Tricyclic Heterocycle Derivatives of Formula (I):and pharmaceutically acceptable salts thereof, wherein R1-R8, A, X and n are as defined herein. The present invention also relates to compositions comprising at least one Fused Tricyclic Heterocycle Derivative, and the Fused Tricyclic Heterocycle Derivatives for use in treating or preventing HIV infection in a subject.