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) (PIVOT-PO)

Inclusion Criteria: Have a diagnosis of cUTI or AP. 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: at least 10 white blood cells (WBCs) per high power field (HPF) in urine sediment at least 10 WBCs per millimeters cubed (mm^3) in unspun urine 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. 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. Exclusion Criteria: Presence of any known or suspected disease or condition that, in the opinion of the Investigator, may confound the assessment of efficacy. Gross hematuria requiring intervention other than administration of study drug or removal/placement of urinary tract instrumentation. Urinary tract surgery within 7 days prior to randomization or urinary tract surgery planned during the study period. Creatinine clearance (CrCl) of ≤30 milliliters per minute (mL/min), as estimated by the Cockcroft-Gault formula. Anticipated concomitant use of non-study antimicrobial drug therapy between randomization and the LFU visit that would potentially effect outcome evaluations of cUTI/AP. Receipt of more than a single dose of a potentially effective antimicrobial within 72 hours prior to study randomization. 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). Pregnant or lactating women. History of epilepsy or known seizure disorder (excluding a history of childhood febrile seizures). History of proven or suspected Clostridioides difficile associated diarrhea. History of human immunodeficiency virus (HIV) infection. QT interval corrected using Fridericia's formula (QTcF) >480 milliseconds (msec) based on screening ECG. History of known genetic metabolism anomaly associated with carnitine deficiency. Requirement for concomitant use of valproic acid, divalproex sodium, or probenecid between randomization and EOT. Note: Other inclusion and exclusion criteria as per protocol may apply.