Interpretation of genotypic resistance to predict darunavir/ritonavir failure in antiretroviral experienced patients

From the Italian Antiretroviral Resistance Cohort Analysis database, 1104 patients starting ritonavir-boosted darunavir-containing regimen were included as follows: 118 subsequently failed treatment at a median of 11 months (interquartile range: 5-20); 3 years failure proportion: 24.6%. HIV Drug Resistance Database and ANRS interpretation algorithms were associated with a progressive risk prediction of virological failure at adjusted Cox. In contrast, Rega algorithm allows to identify a higher number of patients at risk of failure, without losing statistical significance. Four mutations (V32I, I50V, L76V, I84V) were predictive of failure, the hazard ratio progressively increased by detecting 1 (hazard ratio: 2.0, 95% confidence interval: 1.3 to 3.0), 2 (3.6, 2.0 to 6.6), or 3 of them (9.7, 2.8 to 33.5).