1. Intrapatient and interpatient pharmacokinetic variability of raltegravir in the clinical setting.
- Author
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Siccardi M, DʼAvolio A, Rodriguez-Novoa S, Cuenca L, Simiele M, Baietto L, Calcagno A, Moss D, Bonora S, Soriano V, Back DJ, Owen A, and Di Perri G
- Subjects
- Adult, Anti-HIV Agents administration & dosage, Anti-HIV Agents pharmacokinetics, Anti-HIV Agents pharmacology, Atazanavir Sulfate, Drug Interactions, Drug Monitoring, Drug Therapy, Combination, Female, Gene Expression Regulation, Enzymologic, Genetic Variation, Genotype, Humans, Italy, Male, Middle Aged, Oligopeptides pharmacology, Pyridines pharmacology, Raltegravir Potassium, Spain, Glucuronosyltransferase genetics, HIV Integrase Inhibitors pharmacokinetics, Pyrrolidinones pharmacokinetics
- Abstract
Introduction: Raltegravir (RAL) is the first in class integrase inhibitor and is licensed for administration at 400 mg twice daily. RAL pharmacokinetics are characterized by high interpatient variability and recently RAL plasma exposure has been correlated with efficacy. RAL is primarily metabolized by glucuronidation via uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) and UGT1A1*28 considered to be the main genetic variant associated with decreased UGT1A1 expression. This study investigated variability in RAL trough plasma concentrations (Ctrough) in the clinical setting, the effect of UGT1A1*28 and concomitant antiretrovirals., Methods: A total of 86 patients, from Turin, Italy, and Madrid, Spain, were included in the analysis. Blood samples were obtained 10-14 hours postdose. Genotyping for UGT1A1*28 was conducted by sequencing., Results: High interpatient and intrapatient variabilities were observed; 13 patients had ≥3 samples available, and the median coefficient of variation was 128 (64-265). Coadministration of RAL with atazanavir (ATV, n = 9) resulted in higher raltegravir Ctrough, 517 (307-2706) ng/mL when compared with patients not receiving ATV (n = 77) 223 (95-552; P = 0.02). UGT1A1*28 did not influence RAL plasma exposure., Discussion: We have documented large intersubject and intrasubject variabilities in RAL plasma concentrations and confirmed the interaction with ATV. Further studies are required to better understand the mechanisms that influence the pharmacokinetics of RAL.
- Published
- 2012
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