This is a Phase 2, randomized, double blind, placebo and active-controlled, parallel group, multicenter study designed to evaluate the safety and tolerability of VX-152 in Triple Combination (TC) with tezacaftor (TEZ; VX-661) and ivacaftor (IVA; VX-770) in subjects with cystic fibrosis (CF) who are heterozygous for the F508del mutation and a minimal function (MF) CFTR mutation not likely to respond to TEZ and/or IVA therapy (F508del/MF), or who are homozygous for the F508del mutation of the CF transmembrane conductance regulator (CFTR) gene (F508del/F508del).