Safety and efficacy of coformulated efavirenz/emtricitabine/tenofovir single-tablet regimen in treatment-naive patients infected with HIV-1.

Due to the differences between bioavailability of efavirenz (EFV) and tenofovir (TDF), the single-tablet regimen of EFV/emtricitabine (FTC)/TDF is not approved as initial antiretroviral therapy (ART) in Europe by the European Medical Agency. To compare clinical, immunological, and virological outcomes between co-formulated TDF/FTC+EFV and the co-formulated EFV/FTC/TDF single-tablet regimen in patients infected with HIV-1 naive to ART, the data of patients (n = 231) who initiated either TDF/FTC+EFV (n = 155) or EFV/FTC/TDF (n = 76) between January 1, 2007 and June 1, 2010 were analyzed. Changes from baseline to week 48 (TDF/FTC+EFV vs. EFV/FTC/TDF) in HIV plasma load (- 3.25 log vs. -3.32 log) and CD4+ T cell count (+180 vs. +138 cells/mm3) were similar in the two groups. Treatment discontinuation was recorded in 50 (22%) patients (40 on TDF/FTC+EFV and 10 on EFV/FTC/TDF, P = 0.03) but time to discontinuation did not differ between the two groups. Only patients on TDF/FTC+EFV discontinued treatment because of neurological symptoms. Virological failure occurred in 11 (4.7%) patients (seven on TDF/FTC+EFV and four on EFV/FTC/TDF, P = 0.75) with new resistance-associated mutations in five among the six with successful resistance genotype tests. Only baseline resistance-associated mutations was a risk factor for virological failure (P = 0.0146). These data show comparable outcomes between TDF/FTC+EFV or EFV/FTC/TDF used in patients infected with HIV-1 and not treated previously, consistent with a low rate of virological failure in the absence of pretreatment resistance. This would suggest that the European Medical Agency should approve co-formulated EFV/FTC/TDF single-tablet regimen for patients naive to ART.