title: Phenotypic susceptibilities to tenofovir in a large panel of clinically derived human immunodeficiency virus type 1 isolates.
abstract: Tenofovir is a nucleotide analogue human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) inhibitor, and its oral prodrug, tenofovir disoproxil fumarate, has recently been approved for the treatment of HIV-1 infection in the United States. The objective of this study was to characterize the in vitro susceptibility profiles of a large panel of clinically derived HIV-1 isolates for tenofovir. The distribution of tenofovir susceptibilities in over 1,000 antiretroviral-naive, HIV-1-infected individuals worldwide was determined using the Virco Antivirogram assay. In addition, phenotypic susceptibilities to tenofovir and other RT inhibitors were determined in a panel of nearly 5,000 recombinant HIV-1 clinical isolates from predominantly treatment-experienced patients analyzed as a part of routine drug resistance testing. Greater than 97.5% of isolates from treatment-naive patients had tenofovir susceptibilities <3-fold above those of the wild-type controls by the Antivirogram. The clinically derived panel of 5,000 samples exhibited a broad range of antiretroviral drug susceptibilities, including 69, 43, and 16% having >10-fold-decreased susceptibilities to at least one, two, and three antiretroviral drug classes, respectively. Greater than 88% of these 5,000 clinical isolates were within the threefold susceptibility range for tenofovir, and >99% exhibited <10-fold-reduced susceptibilities to tenofovir. Decreased susceptibility to tenofovir was not directly associated with resistance to other RT inhibitors; r(2) values of log-log linear regression plots of susceptibility to tenofovir versus susceptibility to other RT inhibitors were <0.4. The results suggest that the majority of treatment-naive and treatment-experienced individuals harbor HIV that remains within the normal range of tenofovir susceptibilities and may be susceptible to tenofovir disoproxil fumarate therapy.
authors.affiliation: BC Centre for Excellence in HIV/AIDS, St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: P R
authors.initials: PR
authors.lastname: Harrigan
authors.forename: M D
authors.initials: MD
authors.lastname: Miller
authors.forename: P
authors.initials: P
authors.lastname: McKenna
authors.forename: Z L
authors.initials: ZL
authors.lastname: Brumme
authors.forename: B A
authors.initials: BA
authors.lastname: Larder
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D005838:Genotype; D015497:HIV-1 / Q000187:drug effects* / Q000648:ultrastructure; D006801:Humans; D008826:Microbial Sensitivity Tests; D063065:Organophosphonates; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D010641:Phenotype; D012367:RNA, Viral / Q000187:drug effects / Q000235:genetics; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology*; D000068698:Tenofovir
chemical_list: D063065:Organophosphonates; D009943:Organophosphorus Compounds; D012367:RNA, Viral; D018894:Reverse Transcriptase Inhibitors; D000068698:Tenofovir; D000225:Adenine