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Influence of body weight on achieving indinavir concentrations within its therapeutic window in HIV-infected Thai patients receiving indinavir boosted with ritonavir.

ABSTRACT: Indinavir boosted with ritonavir (IDV/r) dosing with 400/100 mg, twice daily, is preferred in Thai adults, but this dose can lead to concentrations close to the boundaries of its therapeutic window. The objectives of this analysis were to validate a population pharmacokinetic model to describe IDV/r concentrations in HIV-infected Thai patients and to investigate the impact of patient characteristics on achieving adequate IDV concentrations. IDV/r concentration data from 513 plasma samples were available. Population means and variances of pharmacokinetic parameters were estimated using a nonlinear mixed effects regression model (NONMEM Version VI). Monte Carlo simulations were performed to estimate the probability of achieving IDV concentrations within its therapeutic window. IDV/r pharmacokinetics were best described by a one-compartment model coupled with a single transit compartment absorption model. Body weight influenced indinavir apparent oral clearance and volume of distribution and allometric scaling significantly reduced the interindividual variability. Final population estimates (interindividual variability in percentage) of indinavir apparent oral clearance and volume of distribution were 21.3 L/h/70 kg (30%) and 90.7 L/70 kg (22%), respectively. Based on model simulations, the probability of achieving an IDV trough concentration greater than 0.1 mg/L was greater than 99% for 600/100 mg and greater than 98% for 400/100 mg, twice daily, in patients weighing 40 to 80 kg. However, the probability of achieving IDV concentrations associated with an increased risk of drug toxicity (greater than 10.0 mg/L) increased from 1% to 10% with 600/100 mg compared with less than 1% with 400/100 mg when body weight decreased from 80 to 40 kg. The validated model developed predicts that 400/100 mg of IDV/r, twice daily, provides indinavir concentrations within the recommended therapeutic window for the majority of patients. The risk of toxic drug concentrations increases rapidly with IDV/r dose of 600/100 mg for patients less than 50 kg and therapeutic drug monitoring of IDV concentrations would help to reduce the risk of IDV-induced nephrotoxicity.

SUBMITTER: Cressey TR

PROVIDER: S-EPMC3058116 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature

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Influence of body weight on achieving indinavir concentrations within its therapeutic window in HIV-infected Thai patients receiving indinavir boosted with ritonavir.

Cressey Tim R TR Urien Saik S Hirt Deborah D Halue Guttiga G Techapornroong Malee M Bowonwatanuwong Chureeratana C Leenasirimakul Prattana P Treluyer Jean-Marc JM Jourdain Gonzague G Lallemant Marc M

Therapeutic drug monitoring 20110201 1

Indinavir boosted with ritonavir (IDV/r) dosing with 400/100 mg, twice daily, is preferred in Thai adults, but this dose can lead to concentrations close to the boundaries of its therapeutic window. The objectives of this analysis were to validate a population pharmacokinetic model to describe IDV/r concentrations in HIV-infected Thai patients and to investigate the impact of patient characteristics on achieving adequate IDV concentrations. IDV/r concentration data from 513 plasma samples were a ...[more]

PMID: 21233689

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Project description:BackgroundAlbuvirtide (ABT), a fusion inhibitor against human immunodeficiency virus (HIV) infection, has good efficacy and tolerability for HIV treatment. However, there is a paucity of data regarding ABT-based regimen as second-line therapy. This current study evaluated the efficacy and safety of switching to ABT + ritonavir-boosted lopinavir (LPV/r) treatment in a cohort of HIV-infected individuals who failed initial treatment.MethodsThis retrospective comparative cohort study included patients who failed initial treatment and switched to either ABT + LPV/r (the ABT group) or two nucleotide reverse transcriptase inhibitors (NRTIs) + LPV/r (the NRTI group) between November 2019 and December 2020 in the People's Hospital of Zhaojue County in Liangshan Yi Autonomous Prefecture, China. All individuals were followed up from baseline to 12 weeks after conversion, or until the patient developed unacceptable toxic effects or was loss of follow-up. The proportion of patients who achieved virological suppression (viral load <50 copies/mL) at week 12 was considered a primary efficacy endpoint. Safety outcomes included the incidence of adverse events and laboratory abnormalities. All participants underwent resistance testing before regimen conversion. The linear regression model was applied to evaluate the association of CD4+ T cell count with the patient's clinical characteristics.ResultsA total of 71 patients were included in this study, the two groups were comparable at baseline in terms of age, sex, CD4+ T cell count, and viral load. The suppression of HIV-1 RNA to levels <50 copies/mL was achieved in 82.4% (28/31) and 29.7% (11/34) of patients in the ABT group and the NRTI group, respectively (P<0.001). Older age (P=0.016) and higher alkaline phosphatase (ALP) levels (P=0.038), but not rescue regimen, were associated with attenuated CD4+ T cell recovery. Most adverse events mild in severity, with abdominal pain as the most reported event in two groups (26.8%, 19/71), and no severe adverse events were detected.ConclusionsConversion to ABT + LPV/r therapy appears to be an effective and safe strategy. This treatment regimen has great potential to be generalized in the HIV-infected population, although further testing in a larger patient population is required to verify these results.

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Dataset Information

Influence of body weight on achieving indinavir concentrations within its therapeutic window in HIV-infected Thai patients receiving indinavir boosted with ritonavir.

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Influence of body weight on achieving indinavir concentrations within its therapeutic window in HIV-infected Thai patients receiving indinavir boosted with ritonavir.

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