Study BT8009-230 in Participants With Locally Advanced or Metastatic Urothelial Cancer (Duravelo-2)

Key Inclusion Criteria:

* Life expectancy ≥ 12 weeks.
* Measurable disease as defined by RECIST v1.1.
* Histologically or cytologically confirmed locally advanced (unresectable) or metastatic UC of the renal pelvis, ureter, bladder, or urethra.
* Archival or fresh tumor tissue comprising primary or metastatic UC should be available for submission to central laboratory.
* Negative pregnancy test for women of childbearing potential (WOCBP) (negative serum test at Screening and negative urine or serum test within 72 hours prior to the first dose).
* Cohort 1: Previously Untreated: Eligible to receive platinum-based chemotherapy (either cisplatin- or carboplatin-based chemotherapy based on Investigator decision.
* Cohort 1: Participants must not have received prior systemic therapy for locally advanced or metastatic UC with the following exceptions:

  1. Prior local intravesical chemotherapy, local surgery when full resection is not achieved, local immunotherapy, and radiotherapy are permitted if completed at least 4 weeks prior to the initiation of study treatment and all acute toxicities have resolved.
  2. Prior neoadjuvant/adjuvant chemotherapy or monomethyl auristatin E (MMAE)-based therapy with recurrence \>12 months from completion of therapy.
  3. Prior neoadjuvant/adjuvant immune checkpoint inhibitor therapy with recurrence \>12 months from completion of therapy.
* Cohort 2: Previously Treated: Participants must have received ≥ 1 prior systemic treatment for locally advanced or metastatic UC. This includes neoadjuvant/adjuvant platinum-based chemotherapy if recurrence occurred within 12 months of completing therapy.
* Cohort 2: Progression or recurrence of UC during or following receipt of most recent therapy.

Key Exclusion Criteria:

* Active keratitis or corneal ulcerations.
* Requirement, while receiving study medications, for treatment with strong inhibitors or strong inducers of human cytochrome P450 3A (CYP3A) or inhibitors of P-glycoprotein (P-gp) including herbal- or food-based inhibitors.
* Any condition requiring current treatment with high dose corticosteroids (\> 10 mg daily prednisone or equivalent).
* Known hypersensitivity or allergy to any of the ingredients of any of the study interventions, or to MMAE.
* Has not adequately recovered from recent major surgery (excluding placement of vascular access).
* Receipt of live or attenuated vaccine within 30 days of first dose.
* Cohort 1: Previously Untreated: Prior treatment with a checkpoint inhibitor (CPI) for any other malignancy within the last 12 months.
* Cohort 2: Previously Treated: Received more than 1 prior platinum-based chemotherapy regimen for locally advanced or metastatic UC. This includes neoadjuvant/adjuvant platinum-based chemotherapy if recurrence occurred within 12 months of completing therapy.
* Cohort 2: Prior treatment with enfortumab vedotin or any other MMAE-based therapy