Vancomycin in Pediatric Patients with Solid or Hematological Malignant Disease: Predictive Performance of a Population Pharmacokinetic Model and New Optimized Dosing Regimens.

BACKGROUND: The application of population pharmacokinetic models and Bayesian methods offers the potential to develop individualized therapeutic approaches. OBJECTIVES: The current study presents an external evaluation of a vancomycin pharmacokinetic model in a pediatric cancer population and proposes an easy-to-use chart for clinicians for a priori vancomycin schedule adaptation to achieve target concentration. METHODS: External evaluation of a population pharmacokinetic model of vancomycin administered via continuous infusion was realized in a new retrospective dataset of pediatric patients with cancer. The published population pharmacokinetic model was implemented in NONMEM 7.3 with the structural and variance parameter values set equal to estimates previously reported. Predictive performance was assessed by quantifying bias and accuracy of model prediction. Normalized prediction distribution errors were also evaluated. Dosage simulations were performed according to the target concentration. RESULTS: A total of 77 patients were included in this study, representing 146 vancomycin courses and 289 concentrations. The model adequately predicted vancomycin concentrations (median prediction error % of - 9.4%, median |PE|% of 24.1%). Based on simulation results, vancomycin dosage (mg/kg) should be adapted for each child on the basis of body weight and cyclosporine coadministration. CONCLUSION: The model previously proposed by Guilhaumou et al. in pediatric patients with solid or hematological malignant disease was externally validated. Simulations have enabled the description of new dosage schedules and creation of a chart to help clinicians adapt vancomycin dosage.

[Field assessment of the new rapid diagnostic test Ebola eZYSCREEN®]. / Validation sur le terrain du nouveau test de diagnostic rapide Ebola eZYSCREEN®.

During the Ebola virus disease outbreak in West Africa in 2014, the World Health Organization has pointed out the need for rapid diagnostic tests (RDT) affordable, sensitive, specific, user-friendly, rapid, equipment-free, and deliverable. The rapid diagnostic test (Lateral Flow Assay) Ebola eZYSCREEN® was developed in this emergency frame using monoclonal antibodies against the envelope glycoprotein of the virus. Two distinct versions have been industrialized, one for whole-blood samples and the other for serum/plasma samples. Both versions have an analytical detection limit of 105 pfu/ml, the stability is at least 393 days at 30°C and 120 days at 45°C. The nonretrospective and independent validation study was carried out in the course of the outbreak in Conakry and at the Ebola Treatment Center of Coyah (Guinea) on 144 patients. In this study, the RDT showed a sensitivity of 65.3% and a specificity of 98.9% on whole blood, a sensitivity of 74.5% and a specificity of 100% on serum. Results from the whole-blood version must be analyzed with caution because of the delay between the blood collection and the completion of the tests, which was out of specification (3 days on average instead of 2 h). In contrast to laboratory tests, this easy to use field test does not require sophisticated instrumentation or even electricity and can contribute to the diagnostic chain of Ebola virus disease taking into account its benefits, high stability, and specificity but also its limit of sensitivity compared to laboratory techniques RT-qPCR (Real-Time reverse transcription Polymerase Chain Reaction), which remain the reference for the diagnosis of Ebola. The RDT Ebola eZYSCREEN® was granted EC IVD (IVD = In Vitro Diagnostic) marking.