Pharmacokinetic/Pharmacodynamic Analysis of Daptomycin Against Staphylococcus aureus and Enterococcus faecium in Pediatric Patients by Monte Carlo Simulation

The objective of this study was to evaluate the efficacy of various daptomycin dosing regimens against Staphylococcus aureus and Enterococcus faecium in pediatric patients with proven/suspected gram‐positive infection. Monte Carlo simulations (MCSs) were conducted using pharmacokinetic (PK) parameters and pharmacodynamic (PD) data to determine the probabilities of target attainment and cumulative fractions of response in terms of area under the concentration curve/minimum inhibition concentration (MIC) targets of daptomycin. According to the results of the MCSs, currently approved pediatric dosage regimens were sufficient against Staphylococcus aureus with MIC ≤ 0.5 μg/mL for all pediatric patients, but poor when MIC ≥ 1 μg/mL except for adolescents (12‐17 years) who need a dosage of ≥10 mg/kg/day at MIC = 1 μg/mL. For Enterococcus faecium with MIC ≤ 4 μg/mL, the recommended dosage of 8‐12 mg/kg/day in adults was enough for adolescents, but not subjected to younger pediatric patients. Furthermore, based on MIC distributions obtained from the European Committee on Antimicrobial Susceptibility Testing, the approved high‐dose regimen should be recommended for infants aged 3‐12 months, children (2‐11 years), and adolescents to achieve better clinical efficacy against methicillin‐resistant Staphylococcus aureus. In addition, the dosage of 8‐12 mg/kg/day was powerful against Enterococcus faecium for adolescents; however, only the highest dosage of 12 mg/kg/day was effective for infants aged 3‐12 months and children. All the simulated regimens were not optimal for infants aged 13‐24 months. These PK/PD‐based simulations rationalize and optimize the dosage regimens of daptomycin against Staphylococcus aureus and Enterococcus faecium in pediatric patients.