Background: Efavirenz and lopinavir/ritonavir are both recommended antiretroviral agents for combination first-line therapy, although information on direct comparisons between them is scarce. A retrospective longitudinal study from the VACH cohort comparing both regimens was performed.
Methods: Efficacy was examined comparing time to virological failure, CD4 recovery and clinical progression. Tolerability was examined comparing time to treatment discontinuation for any reason and for toxicity. Survival analysis was conducted using the Kaplan-Meier method, and standard and weighted Cox regression models.
Results: A total of 1550 antiretroviral-naive patients starting a two-nucleoside reverse transcriptase inhibitor regimen plus either efavirenz (n = 1159) or lopinavir/ritonavir (n = 391) were included in the study. At baseline, patients starting lopinavir/ritonavir had higher HIV-1 RNA and lower CD4+ cell counts. There was no difference in the adjusted hazards of virological failure [efavirenz versus lopinavir/ritonavir hazard ratio (HR) = 0.93, 95% confidence interval (CI): 0.77-1.12, P = 0.43], CD4 recovery (HR = 1.11, 95% CI: 0.95-1.30, P = 0.19) and clinical progression (HR = 0.71, 95% CI: 0.39-1.31, P = 0.27). There was an increased risk of discontinuation for any reason or for toxicity for lopinavir/ritonavir (HR = 2.10, 95% CI: 1.40-3.15, P = 0.0003). CD4 recovery with both drugs was also similar in the lowest CD4 strata. A higher risk of early hypertriglyceridaemia was associated with lopinavir/ritonavir-based regimens.
Conclusions: Our study suggests similar virological efficacy for efavirenz- or lopinavir/ritonavir-based first-line antiretroviral regimens, but an increased risk of discontinuation because of toxicity in case of lopinavir/ritonavir-based therapy. Immunological outcome appeared similar with both regimens.