title: Phenotypic drug susceptibility testing predicts long-term virologic suppression better than treatment history in patients with human immunodeficiency virus infection.
abstract: To assess the value of phenotypic drug susceptibility testing as a predictor of antiretroviral treatment response in human immunodeficiency virus (HIV)-infected people, drug susceptibility testing was performed retrospectively on plasma samples collected at baseline in a cohort of 86 antiretroviral-experienced, HIV-infected people experiencing treatment failure and initiating a new antiretroviral treatment regimen. Two separate criteria for reduced drug susceptibility were evaluated. In multivariate analyses, phenotypic susceptibility was an independent predictor of time to treatment failure (adjusted hazards ratio [HR], 0.70; 95% confidence interval [CI], 0.55-0.90; and adjusted HR, 0.76; 95% CI, 0.61-0.95, with reduced drug susceptibility cutoffs defined as 4.0-fold and 2.5-fold higher than reference virus IC(50) values, respectively). Previous protease inhibitor experience was also a significant independent predictor. Notably, drug susceptibility predicted on the basis of treatment history alone was not predictive of time to treatment failure. In this cohort, phenotypic testing results enhanced the ability to predict sustained long-term suppression of virus load.
authors.affiliation: Division of General Internal Medicine and Birmingham Veterans Affairs Medical Center, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294-0006, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Call
authors.forename: M S
authors.initials: MS
authors.lastname: Saag
authors.forename: A O
authors.initials: AO
authors.lastname: Westfall
authors.forename: J L
authors.initials: JL
authors.lastname: Raper
authors.forename: S V
authors.initials: SV
authors.lastname: Pham
authors.forename: J M
authors.initials: JM
authors.lastname: Tolson
authors.forename: N S
authors.initials: NS
authors.lastname: Hellmann
authors.forename: G A
authors.initials: GA
authors.lastname: Cloud
authors.forename: V A
authors.initials: VA
authors.lastname: Johnson
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology* / Q000627:therapeutic use; D018791:CD4 Lymphocyte Count; D015331:Cohort Studies; D004352:Drug Resistance, Microbial; D018432:Drug Resistance, Multiple; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology; D006801:Humans; D008297:Male; D010641:Phenotype; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012367:RNA, Viral / Q000097:blood; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D012307:Risk Factors; D017211:Treatment Failure; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral; D018894:Reverse Transcriptase Inhibitors