Activity of Elvitegravir, a Once-Daily Integrase Inhibitor, against Resistant HIV Type 1: Results of a Phase 2, Randomized, Controlled, Dose-Ranging Clinical Trial

Background. This phase 2, randomized, active-controlled, 48-week study assessed the noninferiority of the human immunodeficiency virus (HIV) integrase inhibitor elvitegravir to comparator ritonavir-boosted protease inhibitor (CPI/r) in treatment-experienced subjects. Methods. Subjects had HIV RNA levels >= 1000 copies/mL and >= 1 protease resistance mutation. Subjects received nucleoside or nucleotide reverse-transcriptase inhibitors (NRTIs) with or without T-20 and either CPI/r or once- daily elvitegravir at a dose of 20 mg, 50 mg, or 125 mg (blinded to dose) with ritonavir. After week 8, the independent data monitoring committee stopped the elvitegravir 20 mg arm and allowed subjects in the elvitegravir 50 mg and 125 mg arms to add protease inhibitors. The primary end point was the time-weighted average change from baseline in HIV RNA level through week 24 (DAVG(24)). Results. A total of 278 subjects with a median of 11 protease and 3 thymidine analog mutations were randomized and treated. One-half of subjects received NRTIs without expected antiviral activity. Compared with the DAVG(24) for the CPI/r arm (-1.19 log(10) copies/mL), the elvitegravir 50 mg arm was noninferior (-1.44 log(10) copies/mL), and the elvitegravir 125 mg arm was superior (-1.66 log(10) copies/mL; P = . 021). Efficacy was impacted by activity of background agents. There was no relationship between elvitegravir dosage and adverse events. Conclusions. Elvitegravir was well-tolerated and produced rapid virologic suppression that was durable with active background therapy.