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)

Inclusion Criteria:

1. Have a diagnosis of cUTI or AP.

2. Have an adequate urine specimen for evaluation and culture obtained within 24 hoursprior to randomization with evidence of pyuria that includes at least one of thefollowing:

3. at least 10 white blood cells (WBCs) per high power field (HPF) in urinesediment

4. at least 10 WBCs per millimeters cubed (mm^3) in unspun urine

5. positive leukocyte esterase (LE) on urinalysis Note: Participants may berandomized and administered study drug prior to knowledge of urine cultureresults, but pyuria must be documented.

6. Expectation, in the judgment of the Investigator, that the participant will survivewith effective antimicrobial therapy and appropriate supportive care for theanticipated duration of the study.

Exclusion Criteria:

1. Presence of any known or suspected disease or condition that may confound theassessment of efficacy.

2. Gross hematuria requiring intervention other than administration of study drug orremoval/placement of urinary tract instrumentation.

3. Urinary tract surgery within 7 days prior to randomization or urinary tract surgeryplanned during the study period.

4. Creatinine clearance (CrCl) of ≤30 milliliters per minute (mL/min), as estimated bythe Cockcroft-Gault formula.

5. Anticipated concomitant use of non-study antimicrobial drug therapy betweenrandomization and the LFU visit that would potentially effect outcome evaluations ofcUTI/AP.

6. Receipt of a potentially effective antimicrobial within 72 hours prior to studyrandomization.

7. Severe hepatic impairment at Screening, as evidenced by alanine aminotransferase (ALT) or aspartate aminotransferase (AST) >5×upper limit of normal (ULN) or totalbilirubin >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 childhoodfebrile 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 probenecidbetween randomization and EOT.

Note: Other inclusion and exclusion criteria as per protocol may apply.