A Phase 1b/2 Study of B-701 in Treatment of Locally Advanced or Metastatic Urothelial Cell Carcinoma

Key Inclusion Criteria:

• Available tissue that was obtained at or after the time the usbject was found to have muscle invasive disease and is of suitable quality and quantity and to assess the FGFR3 status by genetic testing. For subjects participating in the Randomized Phase only, if suitable archival tissue is unavailable, then a core biopsy of tumor tissue (metastatic or primary) must be obtained prior to randomization even if a blood sample sample was used to determine FGFR3 genetic status
• Stage IV, locally advanced or metastatic urothelial bladder cancer or transitional cell carcinoma arising in another location of the urinary tract, including urethra, ureter, and renal pelvis
• Relapsed after or are refractory to at least one prior line of chemotherapy which have not included a taxane (with the exception of Cohort 3 of the Lead-In Phase which will allow the enrollment of subjects with prior treatment with a taxane)
• At least one prior chemotherapeutic regimen for advanced metastatic/recurrent disease, of which at least one regimen included a platinum agent (unless contraindicated)
• Measurable disease according to RECIST v1.1 criteria
• For Cohort 2, Cohort 3, and the Randomized Phase, tumor must be shown to have an FGFR3 mutation or gene fusion.

Main Exclusion Criteria:

• Prior anti-cancer therapy within 4 weeks prior to Cycle 1, Day 1
• Prior treatment with an inhibitor that is targeted primarily to FGFRs
• Clinically significant comorbid medical conditions or lab abnormalities
• History of major bleeding (requiring a blood transfusion ≥ 2 units) not related to a tumor within the past 12 months
• History of clinically significant coagulation or platelet disorder in the past 12 months
• Currently receiving anticoagulation treatment
• Incomplete healing from wounds from prior surgery
• Weight > 110kg