Lersivirine Almost As Good As Efavirenz — But Not Quite

The investigational nonnucleoside reverse transcriptase inhibitor lersivirine has a unique resistance profile, but what about its safety and efficacy? Data presented at the 6th IAS Conference on HIV Pathogenesis, Treatment and Prevention were somewhat mixed [Vernazza P et al. Abstract TUAB0101].

In an ongoing phase IIb, industry-sponsored study, 195 treatment-naive patients with CD4 counts >200 cells/mm³ were randomized to receive lersivirine (at a dose of 500 or 750 mg once daily) or efavirenz, each together with tenofovir/FTC. At week 48, 79% of patients in the lersivirine groups had viral loads <50 copies/mL, compared with 86% in the efavirenz group. The difference was most apparent among patients with baseline viral loads ≥100,000 copies…