Phase 2, randomised, double-blind, 2-cohort study in hospitalised adults with complicated urinary tract infection (cUTI), including acute pyelonephritis. All study cohorts were randomised in a 2:1 ratio. Treatment duration for each cohort was 7 to 10 days. Patients were not permitted to switch to oral therapy.

Cohort 1: 15 patients treated with cefepime 1 g/AAI101 500 mg intravenous (i.v.) infusion over 2 hours once every 8 hours (q8h), and 7 patients treated with cefepime 1 g i.v. infusion over 2 hours q8h.

Cohort 2: 15 patients treated with cefepime 2 g/AAI101 750 mg i.v. infusion over 2 hours q8h, and 8 patients treated with cefepime 2 g i.v. infusion over 2 hours q8h.

Inclusion criteria:

• Male or female patients with clinical signs and/or symptoms of cUTI or acute pyelonephritis that were expected to require hospitalization and initial treatment with at least 7 days of i.v.

antibiotics.

Exclusion criteria:

• Patients with concurrent infection that would interfere with evaluation of response to the study antibiotics;
• Patients needing concomitant systemic antimicrobial agents in addition to those designated in the various study treatment groups;
• Patients receiving effective antibacterial drug therapy for any indication for a continuous duration of >24 hours during the previous 72 hours before the study-qualifying baseline urine was obtained or receiving any amount of potentially therapeutic antibacterial therapy after collection of the pre-treatment baseline urine culture and before administration of the first dose of study drug;
• Patients likely to require the use of an antibiotic for cUTI or acute pyelonephritis prophylaxis during participation in the study;
• Patients with confirmed fungal urinary tract infection at the screening visit (with ≥103 fungal colony forming units [CFU]/mL); or
• Patients with intractable urinary infection at baseline that the Investigator anticipated would require >10 days of study drug therapy were excluded from participation

Double blind