title: In vitro selection and characterization of VX-478 resistant HIV-1 variants.
abstract: VX-478 (141W94), a potent inhibitor of HIV protease, is in late stage clinical trials for the treatment of HIV infection and AIDS. Resistant viruses were raised in vitro by passage of HIV-1IIIB in the presence of increasing concentrations of VX-478 and the related hydroxyethylamino sulfonamide inhibitor VB-11,328. By direct PCR analysis of selected viruses, a number of mutations were identified (L10F, M46I, I47V, I50V and I84V) in the protease gene. These mutations were introduced into recombinant HIV-1 protease and the mutant enzymes assayed against a panel of inhibitors of diverse chemical structure. For VX-478, significant increases in IC90 and Ki were observed for virus or protease, respectively, containing I50V single mutation or an M46I/I47V/I50V triple mutation. The mutant proteases were also characterized for their kinetic competence to process substrates representing cleavage sites of gag-pol viral polypeptide. The kinetic data were interpreted with the aid of molecular modeling to understand the effect of mutations on inhibitor binding and processing of the gag-pol polypeptide to generate infective virions.
authors.affiliation: Vertex Pharmaceuticals Incorporated, Cambridge, Massachusetts 02139, USA.
authors.forename: S
authors.initials: S
authors.lastname: Pazhanisamy
authors.forename: J A
authors.initials: JA
authors.lastname: Partaledis
authors.forename: B G
authors.initials: BG
authors.lastname: Rao
authors.forename: D J
authors.initials: DJ
authors.lastname: Livingston
mesh_terms: D002219:Carbamates; D004351:Drug Resistance; D005663:Furans; D014644:Genetic Variation; D016333:HIV Protease / Q000737:chemistry / Q000187:drug effects / Q000235:genetics*; D017320:HIV Protease Inhibitors / Q000494:pharmacology; D015497:HIV-1 / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D009154:Mutation; D011487:Protein Conformation; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: D002219:Carbamates; D005663:Furans; D017320:HIV Protease Inhibitors; D013449:Sulfonamides; C095107:VB 11328; C095108:amprenavir; D016333:HIV Protease