Pharmacogenetics of unboosted atazanavir in HIV-infected individuals in resource-limited settings: a sub-study of the AIDS Clinical Trials Group (ACTG) PEARLS study (NWCS 342)

J Antimicrob Chemother. 2016 Jun;71(6):1609-18. doi: 10.1093/jac/dkw005. Epub 2016 Feb 17.


Objectives: The multinational PEARLS (ACTG A5175) study, conducted mainly in resource-limited settings, identified an increased treatment failure rate among HIV-infected individuals randomized to once-daily unboosted atazanavir, didanosine-EC, and emtricitabine compared with efavirenz-based regimens. We evaluated associations between selected human genetic polymorphisms and atazanavir pharmacokinetics in PEARLS.

Methods: Polymorphisms in CYP3A5, ABCB1, SLCO1B1 and NR1I2 were genotyped in PEARLS participants randomized to atazanavir plus didanosine-EC plus emtricitabine in Peru, South Africa and the USA, who also consented to genetic analysis. Non-linear mixed-effects population pharmacokinetic modelling was used to predict atazanavir oral clearance (CL/F) and concentration at 24 h (C24). Atazanavir mono-oxidation metabolites M1 and M2 were quantified from the same single-point plasma sample used to quantify the parent drug. Data were log10 transformed for statistical analysis using unpaired t-tests and one-way ANOVA and are presented as geometric mean (95% CI).

Results: Eighty-four HIV-infected participants were genotyped, including 44 Black Africans or African Americans and 28 women. Median age was 34 years. We identified 56 CYP3A5 expressers and 28 non-expressers. Atazanavir CL/F and C24 did not differ between CYP3A5 expressers and non-expressers: 13.2 (12.1-14.4) versus 12.7 L/h (11.7-13.9), P = 0.61, and 75.3 (46.1-123.0) versus 130.9 ng/mL (86.9-197.2), P = 0.14, respectively. M1/atazanavir and M2/atazanavir ratios were higher in expressers than in non-expressers: 0.0083 (0.0074-0.0094) versus 0.0063 (0.0053-0.0075), P = 0.008, and 0.0065 (0.0057-0.0073) versus 0.0050 (0.0042-0.0061), P = 0.02, respectively.

Conclusions: Expression of CYP3A5 appears to be associated with increased M1 and M2 atazanavir metabolite formation, without significantly affecting parent compound pharmacokinetics.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-HIV Agents / administration & dosage
  • Anti-HIV Agents / pharmacokinetics*
  • Anti-HIV Agents / pharmacology*
  • Atazanavir Sulfate / administration & dosage
  • Atazanavir Sulfate / pharmacokinetics*
  • Atazanavir Sulfate / pharmacology*
  • Female
  • HIV Infections / drug therapy*
  • HIV Protease Inhibitors
  • Humans
  • Male
  • Middle Aged
  • Peru
  • Pharmacogenetics*
  • Polymorphism, Genetic
  • Retrospective Studies
  • South Africa
  • United States
  • Young Adult


  • Anti-HIV Agents
  • HIV Protease Inhibitors
  • Atazanavir Sulfate