Key amprenavir resistance mutations counteract dramatic efficacy of darunavir in highly experienced patients.

In highly experienced HIV-1-infected patients, a ritonavir-boosted darunavir-containing regimen was associated with dramatic immunological and virological efficacy. Patients harbouring viruses with amprenavir-specific resistance profiles, such as I50V or V32I + I47V, failed on a darunavir/ritonavir-containing regimen. These key amprenavir mutations were also selected at the time of failure, suggesting their impact on darunavir efficacy.