A randomized controlled trial of therapeutic drug monitoring in treatment-naive and -experienced HIV-1-infected patients.
ABSTRACT To improve the utility of therapeutic drug monitoring (TDM) by defining the proportion of patients with and predictors of above or below target protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor (NNRTI) concentrations.
This 48-week, multicenter, open-label clinical trial randomized patients to TDM versus standard of care (SOC). Serial pharmacokinetics, including a week-2 3-sample sparse collection, and expert committee TDM recommendations were given to TDM-arm patients' providers.
Seventy-four (39%) of 190 patients had week-2 concentrations outside of targets and 122 (64%) of 190 had nontarget exposure at least once over 48 weeks. Providers accepted 75% of TDM recommendations. Among patients with below-target concentrations, more TDM-arm than SOC-arm patients achieved targets (65% vs. 45%; P = 0.09). Increased body weight and efavirenz or lopinavir/ritonavir use were significant predictors of nontarget concentrations. Patients at target and patients who achieved targets after TDM-directed dose modifications trended toward greater viral load reductions at week 48 than patients with below-target exposures (HIV RNA reductions: 2.4, 2.3, and 1.9 log10 copies/mL, respectively; P = 0.09).
Most patients had nontarget PI and/or NNRTI concentrations over 48 weeks. TDM recommendations were well accepted and improved exposure. Patients below TDM targets trended toward worse virologic response.
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ABSTRACT: Frequency of drug changes in combination antiretroviral therapy among patients starting both tuberculosis (TB) and human immunodeficiency virus (HIV) therapy, as a result of treatment-limiting toxicity or virological failure, is not well established. Patients in the Starting Antiretroviral Therapy at Three Points in Tuberculosis (SAPiT) trial were randomized to initiate antiretroviral therapy either early or late during TB treatment or after completion of TB treatment. Drug changes due to toxicity (defined as due to grade 3 or 4 adverse events) or virological failure (defined as viral load > 1000 copies/ml on two occasions, taken at least 4 weeks apart) were assessed in these patients. A total of 501 TB-HIV co-infected patients were followed for a mean of 16.0 (95% confidence interval (CI): 15.5 to 16.6) months after antiretroviral therapy (ART) initiation. The standard first-line ARVs used, were efavirenz, lamivudine and didanosine. Individual drug switches for toxicity occurred in 14 patients (incidence rate: 2.1 per 100 person-years; 95% (CI): 1.1 to 3.5), and complete regimen changes due to virological failure in 25 patients (incidence rate: 3.7 per 100 person-years; CI: 2.4 to 5.5). The most common treatment limiting toxicities were neuropsychiatric effects (n=4; 0.8%), elevated transaminase levels and hyperlactatemia (n= 3; 0.6%), and peripheral neuropathy (n=2; 0.4%). Complete regimen change due to treatment failure was more common in patients with CD4+ cell count <50cells/mm(3) (p<0.001) at ART initiation and body mass index greater than 25 kg/m(2) (p=0.01) at entry into the study. Both drug switches and complete regimen change were uncommon in patients co-treated for TB-HIV with the chosen regimen. Patients with severe immunosuppression need to be monitored carefully, as they were most at risk for treatment failure requiring regimen change.Antiviral therapy 10/2013; · 3.14 Impact Factor
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ABSTRACT: There is no consensus on darunavir (DRV) target levels in plasma for clinical use, and information about variability in plasma concentrations is limited. AIM:: To investigate the variability in DRV plasma trough concentrations in the clinical setting, evaluating interindividual and intraindividual variabilities of plasma drug levels among HIV-infected patients receiving ritonavir (RTV)-boosted DRV (DRV/r) within salvage regimens, and evaluate the potential correlation between variability and virological response. Sixty-two patients taking DRV/r (600/100 mg twice a day) were evaluated for trough plasma concentrations and immunovirological parameters after 6 months from the start of the regimen. A subgroup of patients (n = 21) was also evaluated for intraindividual variability (expressed as coefficient of variation) on 2 samples taken at different time points. Drug concentrations were assayed by high-performance liquid chromatography with ultraviolet detection, and the values were expressed as medians with interquartile range (IQR). Genotypic sensitivity score and genotypic inhibitory quotient were calculated. DRV/r was used with a median of 3 other antiretroviral drugs (raltegravir use 88.7%). Median plasma concentrations were 3.22 mcg/mL (IQR, 2.04-5.69) for DRV and 0.44 mcg/mL (IQR, 0.21-0.70) for RTV. Both drugs showed a high interindividual variability in plasma concentrations (61% and 99.3%, respectively). Only 3 patients (4.8%) had undetectable DRV plasma levels. DRV plasma concentrations showed a significant positive correlation with age (r = 0.298, P = 0.019), but no significant correlation between DRV genotypic inhibitory quotient and HIV-RNA plasma levels (P = 0.614) was found. Intraindividual coefficients of variation were 58.4% for DRV and 47.1% for RTV. Patients with undetectable HIV-RNA showed a trend for lower intraindividual coefficients of variation compared with patients with detectable HIV-RNA (55.9% versus 83.8%, P = 0.156). No major interaction effects with other antiretroviral drugs were found. In a context of salvage therapy, both DRV and RTV plasma levels showed high interindividual and intraindividual variabilities. Lower intraindividual variability could be beneficial in maintaining viral suppression.Therapeutic drug monitoring 09/2013; · 2.43 Impact Factor
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ABSTRACT: The aim of this analysis was to create a pharmacometric model of efavirenz developmental pharmacokinetics and pharmacogenetics in HIV-infected children. Data consisted of 3,172 plasma concentrations from 96 HIV-1 infected children who participated in the Pediatric AIDS Clinical Trials Group 382 (PACTG382) study. Analyses were performed using NONMEM and the impact of body weight, age, race, sex, formulation, liver function, CYP2B6-G516T and MDR1-C3435T polymorphisms was assessed. A one-compartment model using weight-based allometry on oral clearance and apparent volume of distribution adequately described the data. A sigmoid Emax maturation model demonstrated an increase in oral clearance with age to reach 90% of its mature level by the age of 9 months. The liquid formulation bioavailability relative to the capsule was found to increase with age to reach 90% of its mature value by the age of 8 years. The CYP2B6-G516T polymorphism decreased oral clearance while the MDR1-C3435T polymorphism demonstrated no effect.Antimicrobial Agents and Chemotherapy 10/2013; · 4.57 Impact Factor