title: Population pharmacokinetic-pharmacogenetic study of nevirapine in HIV-infected Cambodian patients.
abstract: The aims of this ANRS12154 open-label, single-center, multiple-dose pharmacokinetic study were to characterize nevirapine pharmacokinetics in a Cambodian population of HIV-infected patients and to identify environmental and genetic factors of variability, focusing on the CYP2B6, CYP3A5, and ABCB1 (MDR1) genes. A total of 170 Cambodian HIV-infected patients were included. Nevirapine trough concentrations were measured after 18 and 36 months of starting antiretroviral treatment and in samples drawn during a dosing interval in a subset of 10 patients. All data were analyzed by nonlinear mixed-effects modeling. The effect of covariates was investigated using the population pharmacokinetic model. Patients carrying homozygous loss-of-function alleles CYP3A5 6986A>G, CYP2B6 516G>T, CYP2B6 1459C>T, and ABCB1 3435C>T represent 42.4%, 9.2%, 0%, and 18% of the population, respectively. The median nevirapine trough concentrations did not differ after 18 and 36 months of treatment (5,705 ng/ml [range, ≤50 to 13,871] and 5,709 ng/ml [range, ≤50 to 15,422], respectively). Interpatient and intrapatient variabilities of nevirapine apparent clearance were 28% and 17%, respectively. CYP2B6 516G>T and creatinine clearance were found to significantly affect nevirapine apparent clearance. The estimated nevirapine apparent clearances were 2.95 liters/h, 2.62 liters/h, and 1.86 liters/h for CYP2B6 516GG, CYP2B6 516GT, and CYP2B6 516TT genotypes, respectively. The impact of creatinine clearance was small. This study demonstrates that 95% of the patients had sustained nevirapine exposure well above the 3,000-ng/ml threshold. Nevirapine clearance was shown to be affected by CYP2B6 516G>T genetic polymorphism and creatinine clearance, although this explained only part of the interpatient variability, which remains low compared to that for other antiretroviral drugs.
authors.affiliation: Rodolphe Mérieux Laboratory, Faculty of Pharmacy, University of Health Sciences, Phnom Penh, Cambodia.
authors.forename: Monidarin
authors.initials: M
authors.lastname: Chou
authors.forename: Julie
authors.initials: J
authors.lastname: Bertrand
authors.forename: Olivier
authors.initials: O
authors.lastname: Segeral
authors.forename: Céline
authors.initials: C
authors.lastname: Verstuyft
authors.forename: Laurence
authors.initials: L
authors.lastname: Borand
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Comets
authors.forename: Clotilde
authors.initials: C
authors.lastname: Le Tiec
authors.forename: Laurent
authors.initials: L
authors.lastname: Becquemont
authors.forename: Vara
authors.initials: V
authors.lastname: Ouk
authors.forename: France
authors.initials: F
authors.lastname: Mentre
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Taburet
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019380:Anti-HIV Agents / Q000097:blood* / Q000493:pharmacokinetics* / Q000627:therapeutic use; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics; D065702:Cytochrome P-450 CYP2B6; D051544:Cytochrome P-450 CYP3A / Q000235:genetics; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D005260:Female; D015658:HIV Infections / Q000097:blood* / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019829:Nevirapine / Q000097:blood* / Q000493:pharmacokinetics* / Q000627:therapeutic use; D010089:Oxidoreductases, N-Demethylating / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics; D055815:Young Adult
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D019380:Anti-HIV Agents; D003577:Cytochrome P-450 Enzyme System; D019829:Nevirapine; D001189:Aryl Hydrocarbon Hydroxylases; C585599:CYP2B6 protein, human; D065702:Cytochrome P-450 CYP2B6; D051544:Cytochrome P-450 CYP3A; D010089:Oxidoreductases, N-Demethylating