ObjectiveWe evaluated the effectiveness of darunavir (DRV) treatment plus an optimized background regimen in 120 HIV-1 treatment-experienced patients.DesignRetrospective cohort, multicenter study.MethodsAdults >16 years with virological treatment failure starting therapy with a DRV-containing regimen were included. Effectiveness was evaluated as the percentage of patients with an undetectable HIV-1 RNA viral load (<50 and <200 copies/mL) after 48 weeks, and changes in CD4+ cell counts. We evaluated the risk factors associated with treatment failure.ResultsOf the cohort, 83 % were men with a median age of 45 years (interquartile range, IQR 40–51). They had experienced treatment for a median of 13 years (IQR 9–17) with a median of six previous regimens (IQR 4–7), all using protease inhibitors. After treatment, 82 % (95 % confidence interval, CI 74–88 %) of patients had an HIV-1 RNA viral load <200 copies/mL and 69 % (95 % CI 60–76 %) had <50 copies/mL. The CD4+ cell count increased by 378 cells/μL (IQR 252–559; P < 0.001 vs. baseline). Risk factors associated with poor outcome were age >40 years [odds ratio, OR 0.15 (95 % CI 0.10–0.78); P = 0.015], use of raltegravir in the regimen [OR 0.37 (95 % CI 0.10–0.97); P = 0.046], and baseline CD4+ cell count <200 cells/μL [OR 2.79 (95 % CI 1.11–6.97); P = 0.028].ConclusionIn this Mexican cohort Darunavir was metabolically safe, well tolerated and achieved high rates of virological suppression in highly treatment-experienced patients infected with HIV-1.