title: Pharmacokinetics of antiretroviral regimens containing tenofovir disoproxil fumarate and atazanavir-ritonavir in adolescents and young adults with human immunodeficiency virus infection.
abstract: The primary objective of this study was to measure atazanavir-ritonavir and tenofovir pharmacokinetics when the drugs were used in combination in young adults with human immunodeficiency virus (HIV). HIV-infected subjects > or =18 to <25 years old receiving (> or =28 days) 300/100 mg atazanavir-ritonavir plus 300 mg tenofovir disoproxil fumarate (TDF) plus one or more other nucleoside analogs underwent intensive 24-h pharmacokinetic studies following a light meal. Peripheral blood mononuclear cells were obtained at 1, 4, and 24 h postdose for quantification of intracellular tenofovir diphosphate (TFV-DP) concentrations. Twenty-two subjects were eligible for analyses. The geometric mean (95% confidence interval [CI]) atazanavir area under the concentration-time curve from 0 to 24 h (AUC(0-24)), maximum concentration of drug in serum (C(max)), concentration at 24 h postdose (C(24)), and total apparent oral clearance (CL/F) values were 35,971 ng x hr/ml (30,853 to 41,898), 3,504 ng/ml (2,978 to 4,105), 578 ng/ml (474 to 704), and 8.3 liter/hr (7.2 to 9.7), respectively. The geometric mean (95% CI) tenofovir AUC(0-24), C(max), C(24), and CL/F values were 2,762 ng.hr/ml (2,392 to 3,041), 254 ng/ml (221 to 292), 60 ng/ml (52 to 68), and 49.2 liter/hr (43.8 to 55.3), respectively. Body weight was significantly predictive of CL/F for all three drugs. For every 10-kg increase in weight, there was a 10%, 14.8%, and 6.8% increase in the atazanavir, ritonavir, and tenofovir CL/F, respectively (P < or = 0.01). Renal function was predictive of tenofovir CL/F. For every 10 ml/min increase in creatinine clearance, there was a 4.6% increase in tenofovir CL/F (P < 0.0001). The geometric mean (95% CI) TFV-DP concentrations at 1, 4, and 24 h postdose were 96.4 (71.5 to 130), 93.3 (68 to 130), and 92.7 (70 to 123) fmol/million cells. There was an association between renal function, tenofovir AUC, and tenofovir C(max) and intracellular TFV-DP concentrations, although none of these associations reached statistical significance. In these HIV-infected young adults treated with atazanavir-ritonavir plus TDF, the atazanavir AUC was similar to those of older adults treated with the combination. Based on data for healthy volunteers, a higher tenofovir AUC may have been expected, but was not seen in these subjects. This might be due to faster tenofovir CL/F because of higher creatinine clearance in this age group. Additional studies of the exposure-response relationships of this regimen in children, adolescents, and adults would advance our knowledge of its pharmacodynamic properties.
authors.affiliation: University of Colorado at Denver and Health Sciences Center, Denver, CO, USA.
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Kiser
authors.forename: Courtney V
authors.initials: CV
authors.lastname: Fletcher
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Flynn
authors.forename: Coleen K
authors.initials: CK
authors.lastname: Cunningham
authors.forename: Craig M
authors.initials: CM
authors.lastname: Wilson
authors.forename: Bill G
authors.initials: BG
authors.lastname: Kapogiannis
authors.forename: Hanna
authors.initials: H
authors.lastname: Major-Wilson
authors.forename: Rolando M
authors.initials: RM
authors.lastname: Viani
authors.forename: Nancy X
authors.initials: NX
authors.lastname: Liu
authors.forename: Larry R
authors.initials: LR
authors.lastname: Muenz
authors.forename: D Robert
authors.initials: DR
authors.lastname: Harris
authors.forename: Peter L
authors.initials: PL
authors.lastname: Havens
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use; D000293:Adolescent; D000328:Adult; D019380:Anti-HIV Agents / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019540:Area Under Curve; D000069446:Atazanavir Sulfate; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D015497:HIV-1 / Q000187:drug effects; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000737:chemistry; D008297:Male; D009842:Oligopeptides / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D063065:Organophosphonates / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D011725:Pyridines / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D018894:Reverse Transcriptase Inhibitors / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019438:Ritonavir / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D000068698:Tenofovir
chemical_list: D019380:Anti-HIV Agents; D009842:Oligopeptides; D063065:Organophosphonates; D011725:Pyridines; D018894:Reverse Transcriptase Inhibitors; D000069446:Atazanavir Sulfate; D000068698:Tenofovir; D000225:Adenine; D019438:Ritonavir