Genotypic resistance profiles associated with virological failure to darunavir-containing regimens: a cross-sectional analysis.

This study aimed at defining protease (PR) resistance mutations associated with darunavir (DRV) failure and PR resistance evolution at DRV failure in a large database of treatment-experienced human immunodeficiency virus (HIV) patients. Overall, 1,104 patients were included: 118 (10.7%) failed at a median observation time of 16 months. The mean number of PR mutations at baseline was 2.7, but it was higher in patients who subsequently failed DRV. In addition, the number of PR mutations increased at failure. The increase in the mean number of mutations was completely related to mutations considered to be associated with DRV resistance following the indications of the main DRV clinical trials. The higher statistical difference at baseline between failing versus non-failing patients was observed for the V32I and I84V mutations. At DRV failure, the major increase was still observed for V32I; I54L, V11I, T74P and I50V also increased. Despite the increment in the mean number of mutations per patient between baseline and failure, in 21 patients (17.8%) at baseline and 36 (30.5%) at failure, no PR mutation was detected. The HIV-DB interpretation algorithm identified few patients with full DRV resistance at baseline and few patients developed full resistance at DRV failure, indicating that complete resistance to DRV is uncommon.