Intrapulmonary Pharmacokinetics of Cefepime and Enmetazobactam in Healthy Volunteers: Towards New Treatments for Nosocomial Pneumonia

Cefepime-enmetazobactam is a novel beta-lactam-beta-lactamase inhibitor combination with broad-spectrum antimicrobial activity against a range of multidrug-resistant Enterobacteriaceae. This agent is being developed for a range of serious hospital infections. An understanding of the extent of partitioning of beta-lactam-beta-lactamase inhibitor combinations into the human lung is required to better understand the potential role of cefepime-enmetazobactam for the treatment of nosocomial pneumonia. A total of 20 healthy volunteers were used to study the intrapulmonary pharmacokinetics of a regimen of 2 g cefepime-1 g enmetazobactam every 8 h intravenously (2 g/1 g q8h i.v.). Each volunteer contributed multiple plasma samples and a single epithelial lining fluid (ELF) sample, obtained by bron-choalveolar lavage. Concentrations of cefepime and enmetazobactam were quantified using liquid chromatography-tandem mass spectrometry. The pharmacokinetic data were modeled using a population methodology, and Monte Carlo simulations were performed to assess the attainment of pharmacodynamic targets defined in preclinical models. The concentration-time profiles of both agents in plasma and ELF were similar. The mean +/- standard deviation percentage of partitioning of total drug concentrations of cefepime and enmetazobactam between plasma and ELF was 60.59% +/- 28.62% and 53.03% +/- 21.05%, respectively. Using pharmacodynamic targets for cefepime of greater than the MIC and free enmetazobactam concentrations of >2 mg/liter in ELF of 20% of the dosing interval, a regimen of cefepime-enmetazobactam of 2 g/0.5 g q8h i.v. infused over 2 h resulted in a probability of target attainment of >= 90% for Enterobacteriaceae with cefepime-enmetazobactam MICs of <= 8 mg/liter. This result provides a rationale to further consider cefepime-enmetazobactam for the treatment of nosocomial pneumonia caused by multidrug-resistant Enterobacteriaceae.

Automated summary

The study revealed that cefepime and enmetazobactam had similar concentration-time profiles in plasma and epithelial lining fluid, with a partitioning of 60.59% and 53.03% between plasma and ELF, respectively. The findings suggest that the cefepime-enmetazobactam regimen may be a promising treatment option for nosocomial pneumonia caused by multidrug-resistant Enterobacteriaceae.