Resistance to amprenavir before and after treatment with lopinavir/ritonavir in highly protease inhibitor-experienced HIV patients

Genotypes in nine highly protease inhibitor (PI)experienced patients were studied before and after lopinavir/ritonavir (LPV/r) treatment. Resistance to amprenavir was the rule both before and after LPV/r treatment. Treatment with LPV/r can select for the 50V mutation. In this setting, significant differences in the inference of the amprenavir phenotype from genotype were observed when using different algorithms.