Evidence Gathered From Randomized Clinical Trials and Observational Studies on the Equivalence of Emtricitabine and Lamivudine

TO THE EDITOR—We read the commentary by Ford et al on our study regarding the comparability of results from trials and cohorts regarding the efficacy of lamivudine (3TC) and emtricitabine (FTC) in combination antiretroviral therapy (ART) [1, 2]. Of course, we can only agree with the statement that evidence from randomized clinical trials (RCTs) is of higher quality than observational studies. But we absolutely cannot agree with the conclusion that the results of the RCTs in the 3 studies Ford et al refer to provide sufficient proof of clinical equivalence of 3TC and FTC in first-line human immunodeficiency virus type 1 (HIV-1) treatment. Actually, 3 RCTs do not even address the main question of our study, which concerned the risk of virological failure in treatment-naive patients starting FTC or 3TC, combined with tenofovir (TDF) specifically in a nucleoside reverse transcriptase inhibitor (NRTI) backbone plus a nonnucleoside reverse transcriptase inhibitor (NNRTI). We specifically focused on patients on TDF plus an NNRTI and FTC or 3TC because these are the most frequently used regimens worldwide.