Randomized participants were stratified and dosed by age group. The selected doses were based on population pharmacokinetic modeling and simulations.18 (link) For participants in the ceftolozane/tazobactam group, those 12 to <18 years of age were given 1.0 g ceftolozane and 0.5 g tazobactam (the dose indicated for adult patients with cUTI),15 and those from birth to <12 years of age were given 20 mg/kg ceftolozane and 10 mg/kg tazobactam (maximum of 1.0 g ceftolozane and 0.5 g tazobactam per dose). All participants in the meropenem group received 20 mg/kg (maximum of 1.0 g per dose), with higher dosing up to 30 mg/kg for participants who were 14 days to <3 months of age permitted at the investigator’s discretion. Each dose of ceftolozane/tazobactam or meropenem was administered as a 60-minute (±10 minutes) infusion and dosed every 8 hours (±1 hour) after the previous infusion.
Treatment duration was 7-14 days. After 3 days (9 doses) of IV therapy, optional open-label, standard-of-care, oral step-down therapy was permitted at the investigator’s discretion, with choice of therapy guided by culture and antibacterial susceptibility results, as well as local standard of care for treatment of cUTI. Recommended options for oral step-down therapy were β-lactam/β-lactamase inhibitor combinations, cephalosporins, fluoroquinolones, nitrofurantoin, trimethoprim‚ or trimethoprim/sulfamethoxazole.
Treatment duration was 7-14 days. After 3 days (9 doses) of IV therapy, optional open-label, standard-of-care, oral step-down therapy was permitted at the investigator’s discretion, with choice of therapy guided by culture and antibacterial susceptibility results, as well as local standard of care for treatment of cUTI. Recommended options for oral step-down therapy were β-lactam/β-lactamase inhibitor combinations, cephalosporins, fluoroquinolones, nitrofurantoin, trimethoprim‚ or trimethoprim/sulfamethoxazole.
