Physiologically Based Pharmacokinetic Model for Predicting Omadacycline Pharmacokinetics and Pharmacodynamics in Healthy and Hepatic Impairment Populations

Purpose

Omadacycline is a new broad-spectrum aminomethylcycline antibiotic. However, there have been limited pharmacokinetic and pharmacodynamic (PK/PD) studies of omadacycline in patients with hepatic impairment. The aim of this study was to explore the PK/PD of omadacycline intravenous administration in healthy and hepatically impaired populations.

Methods

A physiologically based pharmacokinetic (PBPK) model of omadacycline was developed and validated based on published demographic data and the physiochemical properties of omadacycline. The PK processes in healthy adults were simulated and then extrapolated to a hepatically impaired population. Monte Carlo simulations were performed for PD evaluation by calculating the probability of target attainment (PTA) and the cumulative fraction of response (CFR) of the approved dosages.

Findings

In the hepatically impaired population, there was no significant difference in the maximum concentration (C_max) compared with the healthy population, while the area under the plasma concentration-time curve from the first data point extrapolated to infinity (AUC_inf) showed a slight increase. Monte Carlo simulations indicated that the dosage of 200 mg once daily or 100 mg twice daily intravenously (loading dose) and 100 mg once daily intravenously (maintenance dose) could cover the common pathogens of community-acquired bacterial pneumonia (CABP) and acute bacterial skin and skin structure infections (ABSSSI) : Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus.

Implications

Hepatic impairment exerts little impact on the PK properties of omadacycline, and no dosage adjustments are necessary for patients with mild and moderate hepatic impairment. Current dosing regimens are predicted to produce satisfactory therapeutic effects against non–drug-resistant strains of Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae but may not produce the desired AUC/MIC ratios in patients with Escherichia coli or Klebsiella pneumoniae.