Pett SL, Amin J, Horban A, Andrade-Villanueva J, Losso M, Porteiro N, Sierra Madero J, Belloso W, Tu E, Silk D, Kelleher A, Harrigan R, Clark A, Sugiura W, Wolff M, Gill J, Gatell J, Fisher M, Clarke A, Ruxrungtham K, Prazuck T, Kaiser R, Woolley I, Arnaiz JA, Cooper D, Rockstroh JK, Mallon P, Emery S; Maraviroc Switch (MARCH) Study Group.