Inclusion Criteria:

          -  Histologically documented, unresectable locally advanced or metastatic urothelial
             carcinoma

          -  Measurable disease by investigator assessment according to RECIST v1.1

               -  Participants with prior definitive radiation therapy must have measurable disease
                  per RECIST v1.1 that is outside the radiation field or has demonstrated
                  unequivocal progression since completion of radiation therapy

          -  Participants must not have received prior systemic therapy for locally advanced or
             metastatic urothelial carcinoma with the following exceptions:

               -  Participants that received neoadjuvant chemotherapy with recurrence >12 months
                  from completion of therapy are permitted

               -  Participants that received adjuvant chemotherapy following cystectomy with
                  recurrence >12 months from completion of therapy are permitted

          -  Must be considered eligible to receive cisplatin- or carboplatin-containing
             chemotherapy, in the investigator's judgment

          -  Archival tumor tissue comprising muscle-invasive urothelial carcinoma or a biopsy of
             metastatic urothelial carcinoma must be provided for PD-L1 testing prior to
             randomization

          -  Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0, 1, or 2

          -  Adequate hematologic and organ function

        Exclusion Criteria

          -  Previously received enfortumab vedotin or other monomethyl auristatin E (MMAE)-based
             antibody-drug conjugate (ADCs)

          -  Received prior treatment with a programmed cell death ligand-1 (PD-(L)-1) inhibitor
             for any malignancy, including earlier stage urothelial cancer (UC), defined as a PD-1
             inhibitor or PD-L1 inhibitor

          -  Received prior treatment with an agent directed to another stimulatory or co
             inhibitory T-cell receptor

          -  Received anti-cancer treatment with chemotherapy, biologics, or investigational agents
             not otherwise prohibited by exclusion criterion 1-3 that is not completed 4 weeks
             prior to first dose of study treatment

          -  Uncontrolled diabetes

          -  Estimated life expectancy of less than 12 weeks

          -  Active central nervous system (CNS) metastases

          -  Ongoing clinically significant toxicity associated with prior treatment that has not
             resolved to ≤ Grade 1 or returned to baseline

          -  Currently receiving systemic antimicrobial treatment for active infection (viral,
             bacterial, or fungal) at the time of randomization. Routine antimicrobial prophylaxis
             is permitted.

          -  Known active hepatitis B, active hepatitis C, or human immunodeficiency virus (HIV)
             infection.

          -  History of another invasive malignancy within 3 years before the first dose of study
             drug, or any evidence of residual disease from a previously diagnosed malignancy

          -  Documented history of a cerebral vascular event (stroke or transient ischemic attack),
             unstable angina, myocardial infarction, or cardiac symptoms consistent with New York
             Heart Association (NYHA) Class IV within 6 months prior to randomization

          -  Receipt of radiotherapy within 2 weeks prior to randomization

          -  Received major surgery (defined as requiring general anesthesia and >24 hour inpatient
             hospitalization) within 4 weeks prior to randomization

          -  Known severe (≥ Grade 3) hypersensitivity to any enfortumab vedotin excipient
             contained in the drug formulation of enfortumab vedotin

          -  Active keratitis or corneal ulcerations

          -  History of autoimmune disease that has required systemic treatment in the past 2 years

          -  History of idiopathic pulmonary fibrosis, organizing pneumonia, drug induced
             pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening
             chest computed tomography (CT) scan

          -  Prior allogeneic stem cell or solid organ transplant

          -  Received a live attenuated vaccine within 30 days prior to randomization