Cabozantinib in Combination With Enfortumab Vedotin for Locally Advanced or Metastatic Urothelial Cancer

PRIMARY OBJECTIVES:

I. To determine the recommended phase II dose (RP2D) of cabozantinib s-malate (cabozantinib) and enfortumab vedotin 1.25 mg/kg on days 1, 8 and 15 of a 28-day cycle based on safety and tolerability. (Phase I dose escalation) II. To evaluate the ongoing safety and tolerability of cabozantinib and enfortumab vedotin in a dose expansion cohort. (Phase Ib dose expansion)

SECONDARY OBJECTIVES:

I. Obtain preliminary evidence of anti-tumor activity of the combination of cabozantinib and enfortumab vedotin by assessing the objective response rate (ORR) using Response Evaluation Criteria in Solid Tumors (RECIST) version (v)1.1.

II. Progression-free survival (PFS). III. Overall survival (OS). IV. Disease control rate by RECIST v1.1.

EXPLORATORY OBJECTIVES:

I. To assess the pharmacokinetic (PK) profile of cabozantinib during treatment with enfortumab vedotin.

II. To evaluate the effect of the combination on selected biomarkers in the tumor microenvironment, systemic circulation and gut microbiome and their relationship with efficacy of the combination.

III. To evaluate quality of life, frailty and sarcopenia before, during and at the time of treatment completion.

OUTLINE: This is dose-escalation study of cabozantinib.

Patients receive cabozantinib orally (PO) once daily (QD) on days 1-28 and enfortumab vedotin intravenously (IV) on days 1, 8, and 15. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up at 30 days and then every 12 weeks.