Dataset Information

Population pharmacokinetic/pharmacogenetic model for optimization of efavirenz therapy in Caucasian HIV-infected patients.

ABSTRACT: Despite extensive clinical experience with efavirenz (EFV), unpredictable interindividual variabilities in efficacy and toxicity remain important limitations associated with the use of this antiretroviral. The purpose of this study was to determine the factors affecting EFV pharmacokinetics and to develop a pharmacokinetic/pharmacogenetic (PK/PG) model in a Caucasian population of HIV-infected patients. In total, 869 EFV plasma concentrations from 128 HIV-infected patients treated with EFV were quantitatively assessed using a validated high-performance liquid chromatography technique. All patients were genotyped for 90 single nucleotide polymorphisms (SNPs) in genes coding for proteins involved in the metabolism and transport of EFV, using a MassArray platform provided by Sequenom. The influence of these polymorphisms on EFV pharmacokinetics and the effects of demographic, clinical, biochemical, lifestyle, and concurrent drug covariates were evaluated. Plasma concentrations were fitted by a one-compartment model, with first-order absorption and elimination using nonlinear mixed-effect modeling (NONMEM program). The CYP2B6*6 allele, multidrug resistance-associated protein 4 (MRP4) 1497C ? T, and gamma-glutamyltranspeptidase (GGT) were identified as major factors influencing the apparent EFV oral clearance (CL/F), reducing the initial interindividual variability by 54.8%, according to the model CL/F = (12.2 - 0.00279 · GGT) · 0.602(CYP2B6*6 [G/T]) · 0.354(CYP2B6*6 [T/T]) · 0.793(MRP4 1497C ? T), where CYP2B6*6 [G/T], CYP2B6*6 [T/T], and MRP4 1497C ? T take values of 0 or 1 to indicate the absence or presence of polymorphisms. The detailed genetic analysis conducted in this study identified two of 90 SNPs that significantly impacted CL/F, which might indicate that the remaining SNPs analyzed do not influence this PK parameter, at least in Caucasian populations with characteristics similar to those of our study population.

SUBMITTER: Sanchez A

PROVIDER: S-EPMC3195031 | biostudies-literature | 2011 Nov

REPOSITORIES: biostudies-literature

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Population pharmacokinetic/pharmacogenetic model for optimization of efavirenz therapy in Caucasian HIV-infected patients.

Sánchez Almudena A Cabrera Salvador S Santos Dolores D Valverde M Paz MP Fuertes Aurelio A Domínguez-Gil Alfonso A García María J MJ

Antimicrobial agents and chemotherapy 20110906 11

Despite extensive clinical experience with efavirenz (EFV), unpredictable interindividual variabilities in efficacy and toxicity remain important limitations associated with the use of this antiretroviral. The purpose of this study was to determine the factors affecting EFV pharmacokinetics and to develop a pharmacokinetic/pharmacogenetic (PK/PG) model in a Caucasian population of HIV-infected patients. In total, 869 EFV plasma concentrations from 128 HIV-infected patients treated with EFV were ...[more]

PMID: 21896912

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Project description:BACKGROUND: Implication of pharmacogenetic variations and efavirenz pharmacokinetics in concomitant efavirenz based antiviral therapy and anti-tubercular drug induced liver injury (DILI) has not been yet studied. We performed a prospective case-control association study to identify the incidence, pharmacogenetic, pharmacokinetic and biochemical predictors for anti-tubercular and antiretroviral drugs induced liver injury (DILI) in HIV and tuberculosis (TB) co-infected patients. METHODS AND FINDINGS: Newly diagnosed treatment naïve TB-HIV co-infected patients (n?=?353) were enrolled to receive efavirenz based ART and rifampicin based anti-TB therapy, and assessed clinically and biochemically for DILI up to 56 weeks. Quantification of plasma efavirenz and 8-hydroxyefaviernz levels and genotyping for NAT2, CYP2B6, CYP3A5, ABCB1, UGT2B7 and SLCO1B1 genes were done. The incidence of DILI and identification of predictors was evaluated using survival analysis and the Cox Proportional Hazards Model. The incidence of DILI was 30.0%, or 14.5 per 1000 person-week, and that of severe was 18.4%, or 7.49 per 1000 person-week. A statistically significant association of DILI with being of the female sex (p?=?0.001), higher plasma efavirenz level (p?=?0.009), efavirenz/8-hydroxyefavirenz ratio (p?=?0.036), baseline AST (p?=?0.022), ALT (p?=?0.014), lower hemoglobin (p?=?0.008), and serum albumin (p?=?0.007), NAT2 slow-acetylator genotype (p?=?0.039) and ABCB1 3435TT genotype (p?=?0.001). CONCLUSION: We report high incidence of anti-tubercular and antiretroviral DILI in Ethiopian patients. Between patient variability in systemic efavirenz exposure and pharmacogenetic variations in NAT2, CYP2B6 and ABCB1 genes determines susceptibility to DILI in TB-HIV co-infected patients. Close monitoring of plasma efavirenz level and liver enzymes during early therapy and/or genotyping practice in HIV clinics is recommended for early identification of patients at risk of DILI.

Project description:BackgroundENCORE1 demonstrated non-inferiority of daily efavirenz 400 mg (EFV400) versus 600 mg (EFV600) to 96 weeks in treatment-naïve, HIV-infected adults but concerns regarding lower EFV400 concentrations remained. Therefore, relationships between EFV pharmacokinetics (PK) and key genetic polymorphisms with 96-week efficacy and safety were investigated.MethodsRelationships between EFV PK parameters and single nucleotide polymorphisms (SNP; CYP2B6, CYP2A6, CYP3A4, NR1I3, NR1I2, ABCB1) with plasma HIV-RNA (pVL) <200 copies/mL and EFV discontinuation and adverse events at 96 weeks were explored. Receiver operating characteristic curve analysis evaluated the predictability of mid-dose interval (C12) cutoffs and 96-week pVL.ResultsA total of 606 patients (32 % female; 37 % African, 33 % Asian; n = 311 EFV400, n = 295 EFV600) were included. EFV PK parameters, including C12, were not associated with pVL <200 copies/mL at 96 weeks (odds ratio [OR] 5.25, 95 % confidence interval [CI] 0.41-67.90, p = 0.204). Lower risk of CNS-related adverse events was associated with CYP2B6 983TC/CC (OR 0.35, 95 % CI 0.15-0.81, p = 0.015) and higher risk was associated with CYP2B6 15582CT/TT and ABCB1 3435TT (OR 1.46, 95 % CI 1.02-2.09, p = 0.040; OR 2.31, 95 % CI 1.33-4.02, p = 0.003, respectively). Discontinuation due to adverse events (clinician decision) was independently associated with dose (OR 2.54, 95 % CI 1.19-5.43, p = 0.016). C12 between 0.47 and 0.76 mg/L provided sensitivity/specificity >90 % (100 %/92.3 to 98.9 %/92.3 %) for achieving pVL <200 copies/mL at 96 weeks.ConclusionsA higher rate of EFV-related adverse events and discontinuations due to these events for EFV600 were not driven by polymorphisms assessed. Although a single threshold concentration associated with HIV suppression may be clinically useful, it was not viable for ENCORE1. Implementation of EFV400 would improve toxicity management whilst still maintaining good efficacy.

Dataset Information

Population pharmacokinetic/pharmacogenetic model for optimization of efavirenz therapy in Caucasian HIV-infected patients.

Publications

Population pharmacokinetic/pharmacogenetic model for optimization of efavirenz therapy in Caucasian HIV-infected patients.

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