Evaluation of: Gulick RM, Lalezari J, Goodrich J et al. Maraviroc for previously treated patients with R5 HIV-1 infection. N. Engl. J. Med. 359, 1429-1441 (2008). Maraviroc is the first commercially available HIV chemokine receptor antagonist targeting HIV that utilizes the CCR5 chemokine receptor (R5 tropic). The Maraviroc versus Optimized Therapy in Viremic Antiretroviral Treatment-Experienced Patients (MOTIVATE) trials were two randomized, placebo-controlled studies designed to demonstrate the activity of maraviroc in triple-class-experienced HIV individuals, with a primary end point of viral load suppression at 48 weeks. Maraviroc outperformed the placebo plus optimized background (OBT) arm, and exhibited a favorable safety profile with low discontinuation rates, which equaled those of the placebo plus OBT group. The results of these trials led to maraviroc receiving regulatory approval for the treatment of HIV.