• Patients with histologically or cytologically documented, unresectable, locally advanced or metastatic transitional cell carcinoma (transitional cell and mixed transitional/non-transitional cell histologies) of the urothelium (including renal pelvis, ureters, urinary bladder, and urethra)

• Patients who have not been previously treated with first-line chemotherapy. Patients who have received prior definitive chemoradiation, adjuvant or neoadjuvant treatment for locally advanced disease are eligible provided that progression to locally advanced or metastatic disease has occurred \>12 months from the last therapy \[for chemoradiation and adjuvant treatment\] or \>12 months from the last surgery \[for neoadjuvant treatment\].

• At least 1 lesion, not previously irradiated, that qualifies as a RECIST 1.1 target lesion at baseline.

• World Health Organization (WHO)/Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 or 1 at enrolment

• Adequate organ and marrow function as defined in the protocol

• Life expectancy ≥12 weeks in the opinion of the investigator

• Evidence of post-menopausal status, or negative urinary or serum pregnancy test for female pre-menopausal patients.