m8-nelfinavir and HIV-Infections

β-Carotene supplements are often taken by individuals living with HIV-1. Contradictory results from in vitro studies suggest that β-carotene may inhibit or induce cytochrome P450 enzymes and transporters. The study objective was to investigate the effect of β-carotene on the steady-state pharmacokinetics of nelfinavir and its active metabolite M8 in HIV-1 infected individuals. Twelve hour nelfinavir pharmacokinetic analysis was conducted at baseline and after 28 days of β-carotene supplementation (25,000 IU twice daily). Nelfinavir and M8 concentrations were measured with validated assays. Non-compartmental methods were used to calculate the pharmacokinetic parameters. Geometric mean ratios comparing day 28 to day 1 area under the plasma concentration-time curve (AUC(0-12 h)), maximum (C(max)) and minimum (C(min)) concentrations of nelfinavir and M8 are presented with 90% confidence intervals. Eleven subjects completed the study and were included in the analysis. There were no significant differences in nelfinavir AUC(0-12 h) and C(min) (-10%, +4%) after β-carotene supplementation. The M8 C(min) was increased by 31% while the M8 AUC(0-12 h) and C(max) were unchanged. During the 28 day period, mean CD4+ % and CD4+:CD8+ ratio increased significantly (p < 0.01). β-carotene supplementation increased serum carotene levels but did not cause any clinically significant difference in the nelfinavir and M8 exposure.

Topics: Adult; Area Under Curve; beta Carotene; Dietary Supplements; Drug Stability; Female; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Male; Middle Aged; Nelfinavir; Viral Load

Virakinetics II was designed as an observational, multicenter cohort study conducted in HIV-positive patients treated with NFV-based combinations. Trough (pre-dose) concentrations of NFV+M8 in plasma were determined using a novel ELISA test (NFV TDM-ELISA) and analyzed using clinical and laboratory parameters. Drug levels were sorted as below, within or above a given interval (<0.8 microg/mL, 0.8-3.5 microg/mL and >3.5 microg/mL, respectively). Longitudinal analysis was performed in a subset of patients who underwent two or more determinations. Ninety patients on NFV-containing HAART were enrolled and 43 were coinfected with HCV and/or HBV. Among coinfected patients, 10 subjects had a clinical or histological diagnosis of cirrhosis. Compared to the HIV-monoinfected, the coinfected patients were significantly older, more treatment-experienced, with higher frequency of lipodystrophy and altered liver function test values (all p values: <0.05). Coinfected patients were also more likely to be on a reduced dose of NFV than monoinfected (p=0.03). No significant difference was observed between the two groups with regard to NFV+M8 trough values and concentration range distribution. Median NFV+M8 C(trough) concentrations were higher in coinfected patients, but without reaching statistical significance (p=0.2). This new ELISA test proved to be a rapid, convenient and reliable tool for assessing NFV+M8 plasma levels in HIV-positive patients. It could be suitable for use within the framework of routine clinical practice even in peripheral centers without specialized laboratories.

Topics: Adult; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Enzyme-Linked Immunosorbent Assay; Female; Hepatitis B, Chronic; Hepatitis C, Chronic; HIV Infections; Humans; Male; Middle Aged; Nelfinavir; Plasma

* Nelfinavir is an HIV protease inhibitor, substrate of the transporter P-glycoprotein and metabolized via CYP2C19, CYP3A4 and CYP3A5 enzymes. * Pharmacokinetic studies have shown wide interindividual variability of nelfinavir concentrations, some of this variability perhaps caused by variant drug metabolism or transporter genes. * For CYP3A4*1B and CYP3A5*3 polymorphism, results from three studies are in agreement, showing no difference in nelfinavir concentrations between patients with these different genotypes. * However, for MDR1 and CYP2C19 polymorphism, there have been contradictory studies, showing either no impact on nelfinavir concentration or modified concentrations which could influence virological response.. * Patients with an *1/*2 or *2/*2 genotype for CYP2C19 had a nelfinavir to M8 biotransformation divided by 2 compared with *1/*1 patients. * No evidence of any influence of MDR1 polymorphism on nelfinavir absorption could be detected.. To evaluate the effect of CYP2C19 polymorphism on nelfinavir and M8 pharmacokinetic variability in human immunodeficiency virus-infected patients and to study the link between pharmacokinetic exposure and short-term efficacy and toxicity.. Nelfinavir (n = 120) and M8 (n = 119) concentrations were measured in 34 protease inhibitor-naive patients. Two weeks after initiating the treatment, blood samples were taken before, 1, 3 and 6 h after drug administration. Genotyping for CYP3A4, 3A5, 2C19 and MDR1 was performed. A population pharmacokinetic model was developed to describe nelfinavir-M8 concentration time-courses and to estimate interpatient variability. The influence of individual characteristics and genotypes were tested using a likelihood ratio test. Estimated mean (C(mean)), maximal (C(max)) and trough (C(trough)) nelfinavir and M8 concentrations were correlated to short-term virological efficacy and tolerance using Spearman nonparametric correlation tests.. A one-compartment model with first-order absorption, elimination and metabolism to M8 best described nelfinavir data. M8 was modelled by an additional compartment. Mean pharmacokinetic estimates and the corresponding intersubject variabilities were: absorption rate 0.17 h(-1) (99%), absorption lag time 0.82 h, apparent nelfinavir total clearance 52 l h(-1) (49%), apparent nelfinavir volume of distribution 191 l, M8 elimination rate constant 1.76 h(-1) and nelfinavir to M8 0.39 h(-1) (59%) in *1/*1 patients and 0.20 h(-1) in *1/*2 or *2/*2 patients for CYP2C19*2. Nelfinavir C(mean) was positively correlated to glycaemia and triglyceride increases (P = 0.02 and P = 0.04, respectively).. The rate of metabolism of nelfinavir to M8 was reduced by 50% in patients with *1/*2 or *2/*2 genotype for CYP2C19 compared with those with *1/*1 genotype.

Topics: Adult; Aryl Hydrocarbon Hydroxylases; Biotransformation; Body Weight; Cytochrome P-450 CYP2C19; Cytochrome P-450 CYP3A; Dose-Response Relationship, Drug; Female; Genotype; HIV Infections; HIV Protease Inhibitors; Humans; Male; Middle Aged; Mixed Function Oxygenases; Nelfinavir; Polymorphism, Genetic; Treatment Outcome; Viral Load

Therapeutic drug monitoring (TDM) is an important tool in the management of antiretroviral (ARV) therapy. The gold standard for measuring drugs plasma levels is High-Performance Liquid Chromatographic Assay (HPLC) however it is technically-demanding and time-consuming. We evaluated a new immunoenzymatic test (TDM-ELISA, Biostrands, Trieste, Italy) for nelfinavir and its active metabolite M8 in comparison with HPLC. A statistically significant difference in Ctrough between the two different tests was demonstrated but this difference was no longer significant when a value of 29% due to M8 aliquot was deleted. This faster TDM-ELISA may have an important role for TDM in HIV patients taking ARVs.

Topics: Anti-Retroviral Agents; Antiretroviral Therapy, Highly Active; Drug Monitoring; Enzyme-Linked Immunosorbent Assay; Female; HIV Infections; HIV Protease Inhibitors; Humans; Male; Nelfinavir; Reagent Kits, Diagnostic; Sensitivity and Specificity