This study will be a single-blind, randomised, multi-centre, active controlled trial. Patients aged from 3 months to less than 18 years with complicated urinary tract infections (cUTIs) will be randomised to 1 of 2 treatment groups (3:1 ratio): Ceftazidime and avibactam (CAZ AVI )or cefepime. Randomisation will be stratified by age cohort.~Patients will receive intravenous (IV) treatment for a minimum of 72 hours (3 full days, ie, 9 doses if given 3 times daily, or 6 doses if given twice daily) before having the option to switch to an oral therapy . The decision to switch to oral therapy is entirely at the Investigator's discretion, if the patient has good or sufficient clinical response, and the patient is tolerating oral fluids or food.~Patients will be assessed for safety and efficacy throughout the study, and blood samples will be taken for pharmacokinetic assessment. The duration of each patient's participation in the study will be a minimum of 27 days to a maximum of 50 days after start of study treatment including (intravenous treatment or oral switch therapy) 7 to 14 days of active treatment. The late follow-up visit (LFU) is to be performed 20 to 36 days after the last dose of any treatment.~The assessments at the test of cure (TOC) visit should be performed in person 8 to 15 days after last dose of any study drug Maximum duration of study drug or oral switch therapy is up to Day 14.
This study will assess the safety, tolerability and efficacy of ceftazidime and avibactam (CAZ-AVI )versus cefepime in children from 3 months to less than 18 years old with complicated urinary tract infections.