Pazopanib in Treating Patients With Metastatic Urothelial Cancer

This phase II trial is studying the side effects and how well pazopanib works in treating patients with metastatic urothelial cancer. Pazopanib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth and by blocking blood flow to the tumor.

PRIMARY OBJECTIVES: I. Assess the anti tumor activity and toxicity profile of pazopanib hydrochloride in patients with metastatic urothelial cancer. SECONDARY OBJECTIVES: I. Evaluate the pharmacokinetics of pazopanib hydrochloride in these patients. II. Evaluate pre- and post-treatment changes in circulating endothelial cells, monocytes and platelets, and angiogenesis-related factors in these patients. OUTLINE: This is a multicenter study. Patients receive oral pazopanib hydrochloride once daily on days 1-28. Treatment repeats every 28 days in the absence of disease progression or unacceptable toxicity. Patients undergo blood collection periodically for correlative studies and pharmacological studies. Samples are analyzed for vascular endothelial growth factor (VEGF) and soluble VEGF receptor II concentration via ELISA. Circulating endothelial cells are also measured. After completion of study treatment, patients are followed for 1 year.