A Study of Oral Tebipenem Pivoxil Hydrobromide (TBP-PI-HBr) Compared to Intravenous Imipenem-cilastatin in Participants With Complicated Urinary Tract Infection (cUTI) or Acute Pyelonephritis (AP)

Eligibility Criteria

• 1. Have a diagnosis of cUTI or AP.
• 2. Have an adequate urine specimen for evaluation and culture obtained within 24 hours prior to randomization with evidence of pyuria that includes at least one of the following:
• 1. at least 10 white blood cells (WBCs) per high power field (HPF) in urine sediment
• 2. at least 10 WBCs per millimeters cubed (mm\^3) in unspun urine
• 3. positive leukocyte esterase (LE) on urinalysis Note: Participants may be randomized and administered study drug prior to knowledge of urine culture results, but pyuria must be documented.
• 3. Expectation, in the judgment of the Investigator, that the participant will survive with effective antimicrobial therapy and appropriate supportive care for the anticipated duration of the study.
• 1. Presence of any known or suspected disease or condition that may confound the assessment of efficacy.
• 2. Gross hematuria requiring intervention other than administration of study drug or removal/placement of urinary tract instrumentation.
• 3. Urinary tract surgery within 7 days prior to randomization or urinary tract surgery planned during the study period.
• 4. Creatinine clearance (CrCl) of ≤30 milliliters per minute (mL/min), as estimated by the Cockcroft-Gault formula.
• 5. Anticipated concomitant use of non-study antimicrobial drug therapy between randomization and the LFU visit that would potentially effect outcome evaluations of cUTI/AP.
• 6. Receipt of a potentially effective antimicrobial within 72 hours prior to study randomization.
• 7. Severe hepatic impairment at Screening, as evidenced by alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \>5×upper limit of normal (ULN) or total bilirubin \>3×ULN, or clinical signs of cirrhosis or end-stage hepatic disease (e.g., ascites, hepatic encephalopathy).
• 8. Pregnant or lactating women.
• 9. History of epilepsy or known seizure disorder (excluding a history of childhood febrile seizures).
• 10. History of proven or suspected Clostridioides difficile associated diarrhea.
• 11. History of human immunodeficiency virus (HIV) infection.
• 12. QT interval corrected using Fridericia's formula (QTcF) \>480 milliseconds (msec) based on screening ECG.
• 13. History of known genetic metabolism anomaly associated with carnitine deficiency.
• 14. Requirement for concomitant use of valproic acid, divalproex sodium, or probenecid between randomization and EOT.