1302. Cefiderocol Population Pharmacokinetics and Probability of Target Attainment in Plasma and Epithelial Lining Fluid in Patients with Pneumonia, Bloodstream Infection/Sepsis, or Complicated Urinary Tract Infections

BACKGROUND: Cefiderocol (CFDC) is a novel siderophore cephalosporin with activity against a broad range of Gram-negative bacteria. The aim of this study was to perform population pharmacokinetic (PopPK) analysis and evaluate probability of target attainment (PTA) in plasma and epithelial lining fluid (ELF) based on a modeling and simulation approach. METHODS: PopPK analysis in plasma was conducted using 3427 concentration data from 425 patients with pneumonia, bloodstream infection/sepsis (BSI/sepsis), complicated urinary tract infection (cUTI), or acute uncomplicated pyelonephritis in 3 Phase 2 or 3 studies (NCT03032380, NCT02714595, and NCT02321800), and 91 subjects without any infection in Phase 1 studies. In addition, intrapulmonary modeling was conducted using ELF concentration data from 7 pneumonia patients (NCT03862040) and 20 healthy subjects. Monte-Carlo simulations were performed by generating 1000 virtual patients for each infection site (pneumonia, BSI/sepsis, or cUTI) to predict PTA for 75% of time for which free drug concentration in plasma or ELF (only pneumonia patients) exceeds the minimum inhibitory concentration (MIC; 0.25–16 µg/mL) over dosing interval following CFDC 2 g q8h infused over 3 hours with dose adjustment based on renal function, including augmented renal clearance. RESULTS: The developed PopPK model described the plasma and ELF CFDC concentrations. Creatinine clearance, body weight, infection site, and albumin concentration were statistically significant covariates on CFDC PK in plasma. There were no clinically significant differences in CFDC plasma exposure based on infection site or with/without ventilation. The penetration ratio of ELF to free plasma in pneumonia patients (0.340) was 1.3-fold higher than that in healthy subjects (0.263). As shown in the table below, plasma PTA was >90% against MICs ≤4 μg/mL, regardless of infection site and renal function. ELF PTA in pneumonia patients was >90% against MICs ≤2 μg/mL and >85% against MICs ≤4 μg/mL, regardless of renal function. Table. Probability of Target Attainment for 75% fT>MIC or 75% fT>MIC,ELF [Image: see text] CONCLUSION: The recommended dosing regimen (2 g, q8h, 3-hr infusion) adjusted by renal function provided adequate exposure to CFDC in patients with infections caused by Gram-negative pathogens, irrespective of infection site and renal function. DISCLOSURES: Takayuki Katsube, PhD, Shionogi & Co., Ltd. (Employee) Nao Kawaguchi, BPharm, Shionogi & Co., Ltd. (Employee) Roger Echols, MD, Shionogi Inc. (Consultant) Toshihiro Wajima, PhD, Shionogi & Co., Ltd. (Employee) David P. Nicolau, PharmD, Cepheid (Other Financial or Material Support, Consultant, speaker bureau member or has received research support.)Merck & Co., Inc. (Consultant, Grant/Research Support, Speaker’s Bureau)Wockhardt (Grant/Research Support)