Similar antiviral efficacy and tolerability between efavirenz and lopinavir/ritonavir, administered with abacavir/lamivudine (Kivexa®), in antiretroviral-naïve patients: A 48-week, multicentre, randomized study (Lake Study)

BackgroundAlthough efavirenz and lopinavir/ritonavir(r) are both recommended antiretroviral agents in antiretroviral-naïve HIV-infected patients, there are few randomized comparisons of their efficacy and tolerability.MethodsA multicenter and randomized study was performed including 126 antiretroviral-naïve patients, randomly assigned to efavirenz + Kivexa® (n = 63) or lopinavir/r + Kivexa® (n = 63). Efficacy endpoints were the percentage of patients with HIV-RNA ≤50 copies/mL at week 48 and CD4 recovery. Safety was assessed by comparing toxicity and discontinuations. Statistical analyses were performed on an intention-to-treat (ITT) basis (Missing = Failure).ResultsAt week 48, 56.7% of patients in the efavirenz and 63.2% in the lopinavir/r groups showed HIV-1 RNA <50 copies/mL (P = 0.770) (intention-to-treat analysis; Missing = Failure). Only 1 (1.53%) patient from each group experienced virological failure. CD4 values increased in both groups (298 cells in the efavirenz group, P = 0.001; 249 cells in the lopinavir/r group, P = 0.002; P = 0.126 between groups). HDL-cholesterol only increased in the efavirenz group (from 39 ± 12 mg/dL to 49 ± 11; P = 0.001). Discontinuations were more frequent in the lopinavir/r group (36.5% versus 28.5%; P = 0.193), but more patients with efavirenz interrupted due to toxicity (11.1% versus 6.3%); most of them were attributed to hypersensitivity reaction.ConclusionsSimilar virological efficacy was observed for efavirenz and lopinavir/r, when administered with Kivexa® in antiretroviral-naïve patients, while immunological improvement was slightly superior for efavirenz. The higher rate of discontinuation due to toxicity in the efavirenz group was related to a higher incidence of hypersensitivity reaction. Nowadays, the use of the new formulation of lopinavir/r and the HLA-B*5701 genotype test before starting abacavir should improve the safety profiles of these regimens.