title: Drug resistance genotypes predict response to amprenavir-containing regimens in highly drug-experienced HIV-1-infected patients.
abstract: We have undertaken a study of virological responses to amprenavir-containing antiretroviral regimens, during the expanded access programme within the UK. Ninety-five HIV-1-infected patients were included for which virological and immunological follow-up was available for 75, and baseline drug resistance data available for 51. These were highly drug-experienced patients, having previously received a median of nine antiviral drugs, within all available classes. Eighty-eight percent of patients had a virological response to the new regimen, with a median maximal decline of 1.45 log10 copies/ml, and 34% of patients reached <400 copies/ml on treatment. Although 68% of patients with resistance data had protease inhibitor resistance mutations, only 10% patients had key amprenavir resistance mutations, and virological response was predicted by the number of active drugs utilized in the amprenavir-containing regimen, as determined by the baseline genotypic resistance test. Other independent predictors of viral load decline were a higher baseline viral load and fewer previous antiviral drugs. We conclude that amprenavir can contribute to antiviral efficacy in salvage regimens, and that resistance testing may help to optimize its use in this scenario. New formulations of amprenavir, together with boosted regimens, may enhance the activity in the presence of protease inhibitor-resistant virus.
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology / Q000627:therapeutic use; D002219:Carbamates; D024882:Drug Resistance, Viral / Q000235:genetics*; D004359:Drug Therapy, Combination; D005260:Female; D005663:Furans; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D016333:HIV Protease / Q000235:genetics; D017320:HIV Protease Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008297:Male; D009154:Mutation; D011237:Predictive Value of Tests; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D016879:Salvage Therapy; D013449:Sulfonamides / Q000008:administration & dosage / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D019380:Anti-HIV Agents; D002219:Carbamates; D005663:Furans; D017320:HIV Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors; D013449:Sulfonamides; C095108:amprenavir; D054303:HIV Reverse Transcriptase; D016333:HIV Protease