The ACTG A5303 study at CROI 2015 was a double-blind, randomized trial that compared maraviroc (Selzentry, Celsentri), at 150 mg once daily, to tenofovir (TDF, Viread) in 259 treatment-naive patients, both arms with ritonavir (Norvir)-boosted darunavir (Prezista) plus emtricitabine (FTC, Emtriva). The main endpoint was toxicity, and not surprisingly the TDF-sparing maraviroc arm showed statistically-significant lower bone loss in bone DXA at 48 weeks.
Despite the promising results, the main jewel of the study remained unnoticed to most CROI attendants. In a secondary endpoint in the study, maraviroc had a 48-week efficacy (viral load < 50 copies/mL) of 86% versus 81% in the TDF arm. Despite not being a non-inferiority trial, this difference would meet non-inferiority with the commonly used statistical margin of 10 to 12%. Therefore, the once-daily regimen of maraviroc, emtricitabine and darunavir/ritonavir could become a new alternative for individuals who are not candidates for TDF.