Pharmacokinetics and pharmacodynamics of intravenous delafloxacin in healthy subjects: model-based dose optimization

ABSTRACT Delafloxacin, a fluoroquinolone antibiotic to treat skin infections, exhibits a broad-spectrum antimicrobial activity. The first randomized, open-label phase I clinical trial was conducted to assess the safety and pharmacokinetics (PK) of intravenous delafloxacin in the Chinese population. A population pharmacokinetic (PopPK) model based on the clinical trial was conducted by NONMEM software. Monte Carlo simulation was performed to evaluate the antibacterial effects of delafloxacin at different doses in different Chinese populations. The PK characteristics of delafloxacin were best described by a three-compartment model with mixed linear and nonlinear clearance. Body weight was included as a covariate in the model. We simulated the AUC 0-24h in a steady state at five doses in patient groups of various weights. The results indicated that for patients weighing 70 kg and treated with methicillin-resistant Staphylococcus aureus (MRSA) infections, a minimum dose of 300 mg achieved a PTA > 90% at MIC 90 of 0.25 µg/mL, suggesting an ideal bactericidal effect. For patients weighing less than 60 kg, a dose of 200 mg achieved a PTA > 90% at MIC 90 of 0.25 µg/mL, also suggesting an ideal bactericidal effect. Additionally, this trial demonstrated the high safety of delafloxacin in single-dose and multiple-dose groups of Chinese. Delafloxacin (300 mg, q12h, iv) was recommended for achieving optimal efficacy in Chinese bacterial skin infections patients. To ensure optimal efficacy, an individualized dose of 200 mg (q12h, iv) could be advised for patients weighing less than 60 kg, and 300 mg (q12h, iv) for those weighing more than 60 kg.