Simulation-Based Evaluation of PK/PD Indices for Meropenem Across Patient Groups and Experimental Designs

Anders N Kristoffersson1, Pascale David-Pierson2, Neil J Parrott2

  • 1Department of Pharmaceutical Biosciences, Uppsala Universitet, Box 591, Uppsala, SE-751 24, Sweden. anders.kristoffersson@farmbio.uu.se.

Pharmaceutical Research
|January 21, 2016
PubMed
Abstract

Insights

Antibiotic dose predictions using PK/PD indices are sensitive to drug susceptibility and pharmacokinetics. Simulations suggest an integrated PK-PKPD model is preferable to fixed targets for meropenem dosing against Pseudomonas aeruginosa.

Area of Science:

  • Pharmacology
  • Microbiology
  • Computational Biology

Background:

  • Pharmacokinetic/pharmacodynamic (PK/PD) indices are crucial for predicting antibiotic efficacy.
  • Current models often assume PK/PD index insensitivity to factors like bacterial susceptibility and pharmacokinetics (PK).
  • Meropenem and Pseudomonas aeruginosa serve as a model system to challenge these assumptions.

Purpose of the Study:

  • To evaluate the sensitivity of PK/PD indices to experimental design, bacterial susceptibility, and PK variability.
  • To challenge the assumption that PK/PD index type and magnitude are independent of these factors.
  • To compare the predictive performance of different PK/PD indices for meropenem.

Main Methods:

  • In silico replication of a published murine dose fractionation study.
  • Evaluation of PK/PD index sensitivity to variations in MIC, PK profiles, and experimental design.
  • Utilizing a longitudinal PK/PD model based on in vitro data.

Main Results:

  • The time above the minimum inhibitory concentration (fT>MIC) best predicted outcomes in the murine model.
  • Predictive capacity shifted to the area under the concentration-time curve divided by MIC (AUC/MIC) with increased dosing frequency.
  • Both indices' magnitudes were sensitive to bacterial susceptibility, and human PK data showed similar predictive capacities for fT>MIC and AUC/MIC.

Conclusions:

  • A PK/PD model successfully predicted in vivo meropenem study outcomes.
  • PK/PD index type and magnitude are sensitive to experimental design, MIC, and PK.
  • Integrated PK-PKPD modeling is recommended over fixed PK/PD targets for optimizing antibiotic dosing.

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