Individualized Cefepime Dosing Study

Summary

Several population pharmacokinetic (PK) models for cefepime in critically ill patients have been described, all indicating that variability in renal clearance is the main determinant of observed variability in exposure. The main objective of this study was hence to determine which renal marker best predicts cefepime clearance.

Conditions

• Antimicrobial Treatment

Interventions

DRUG

Cefepime dosing

Patients will received cefepime administered per standard-of-care as a 30 min intravenous infusion. Dosing will be based on local guidelines (the Sanford guide to antimicrobial therapy 2012-2013) using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine formula to estimate glomerular filtration rate (GFR).

OTHER

Blood sampling

Blood will be sampled immediately prior to dose administration (time = 0 at the start of the 30 min infusion), at 0.5, 1, 3, 5 hours post-start of infusion and just before the subsequent dose. From day two onwards, samples will be taken at the end of the infusion and just before the next dose. For the quantification of cefepime, a validated solid phase extraction-liquid chromatography electrospray-tandem mass spectrometry method will be used.

OTHER

Urine sampling

Timed urine collections were taken during one dosing interval (8 hours in a three times daily regimen) every day.

OTHER

Determination of renal markers

Creatinine (modified Jaffe method) and urea in serum will be determined using an Architect c16000 analyzer (Abbott, Chicago, IL, USA). Cystatin C will be determined using a particle-enhanced immunonephelometric assay (N Latex Cystatin C, Siemens Healthcare Diagnostics, Marburg, Germany) by use of a BN II nephelometer (Siemens Healthcare Diagnostics). This assay has a calibration traceable to the first certified reference material for cystatin C in human serum (ERM-DA471/IFCC). Kidney injury molecule-1 (KIM-1) in urine and uromodulin in serum will be determined using commercially available ELISA assays: Quantikine ELISA Human TIM-1/KIM-1/HAVCR (R\&D Systems, Minneapolis, MN, USA) and Uromodulin ELISA (Euroimmun, Luebeck, Germany), respectively.

OTHER

Population pharmacokinetic modeling

The cefepime concentration versus time data will be fitted using the FOCE-I estimation algorithm in NONMEM® (Version 7.3; GloboMax LLC, Hanover, MD, USA). R® (R foundation for statistical computing, Vienna, Austria) will be used to graphically assess the model's goodness-of-fit and to evaluate the model's predictive capabilities. As a measure of prediction error, the absolute prediction error (APE) will be used. In short, the measured cefepime concentrations for each individual i at time point j were compared against the population predicted cefepime concentrations, i.e. the predictions for each individual without taking into account the between-subject variability (PRED in NONMEM). The distribution of APEs will be summarized by the median and 90% percentile.

OTHER

Covariate screening

Renal function will be assessed by four serum based kidney markers (serum creatinine, cystatin C, urea and uromodulin) and two urinary markers (measured creatinine clearance (CrCl) and KIM-1, both on timed urine collections). Serum creatinine and cystatin C will also be used to calculate the eGFR based on CKD-EPI formulas.

OTHER

Monte Carlo simulations

Based on the final covariate model, a Monte Carlo-based simulation study will be performed to evaluate the Sanford dose recommendations for ICU patients.

Sponsors & Collaborators

• University Ghent

  collaborator OTHER

• Onze Lieve Vrouw Hospital

  lead OTHER

Principal Investigators

• Stijn Jonckheere · Onze Lieve Vrouw Hospital

Study Design

Allocation

NA

Purpose

TREATMENT

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2014-03-31

Primary Completion

2015-07-31

Completion

2016-01-31