Pazopanib in Treating Patients With Metastatic Urothelial Cancer

Inclusion Criteria: * Histologically or cytologically confirmed transitional cell cancer of the urothelium or bladder * Metastatic disease * Measurable disease, defined as ≥ 1 unidimensionally measurable lesion ≥ 2.0 cm by conventional techniques OR ≥ 1.0 cm by spiral CT scan * No known brain metastases * ECOG performance status 0-2 * Life expectancy ≥ 12 weeks * Platelet count ≥ 100,000/mm\^3 * WBC ≥ 3,000/mm\^3 * Absolute neutrophil count ≥ 1,500/mm\^3 * Bilirubin normal * AST and ALT ≤ 2.5 times upper limit of normal (ULN) * Creatinine normal OR creatinine clearance ≥ 60 mL/min * PT/INR/PTT ≤ 1.2 times ULN * No proteinuria \> 1+ on two consecutive dipsticks measured ≥ 1 week apart * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No history of allergic reactions attributed to compounds of similar chemical or biological composition to pazopanib hydrochloride or other agents used in the study * No condition that impairs the ability to swallow and retain pazopanib hydrochloride tablets, including any of the following: * Gastrointestinal tract disease resulting in an inability to take oral medication * Requirement for IV alimentation * Prior surgical procedures affecting absorption * Active peptic ulcer disease * No uncontrolled illness that would limit compliance with study therapy including, but not limited to, any of the following: * Ongoing or active infection * Psychiatric illness or social situations * No QTc prolongation (defined as a QTc interval ≥ 480 msecs) or other significant ECG abnormalities (e.g., frequent ventricular ectopy, evidence of ongoing myocardial ischemia) * No other conditions, including any of the following: * Serious or non-healing wound, ulcer, or bone fracture * Abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within the past 28 days * Cerebrovascular accident within the past 6 months * Myocardial infarction, cardiac arrhythmia, or admission for unstable angina within the past 12 weeks * Venous thrombosis within the past 12 weeks * New York Heart Association (NYHA) class III or IV heart failure * Asymptomatic NYHA class II heart failure on treatment allowed * No other active second malignancy other than non-melanoma skin cancer * Patients are not considered to have an active malignancy if they have completed anti-cancer therapy and are considered by their physician to be ≤ 30% risk of relapse * At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin C) and recovered * At least 4 weeks since prior radiotherapy * Prior palliative radiotherapy to metastatic lesions allowed provided there is ≥ 1 measurable and/or evaluable lesion(s) that has not been irradiated * At least 4 weeks since prior surgery * One prior chemotherapy regimen for metastatic urothelial or bladder cancer * More than 12 weeks since prior cardiac angioplasty or stenting * Prior adjuvant or neoadjuvant therapy allowed * No prior experimental treatment for metastatic disease * No other prior or concurrent investigational agents * No concurrent combination antiretroviral therapy for HIV-positive patients * No concurrent CYP2C9 substrates, including any of the following: * Anticoagulants (e.g., warfarin \[therapeutic doses only\]) * Low molecular weight heparin and prophylactic low-dose warfarin (≤ 2 mg daily) allowed * Oral hypoglycemics (e.g., glipizide, glyburide, tolbutamide, glimepiride, or nateglinide) * Ergot derivatives (e.g., dihydroergotamine, ergonovine, ergotamine, or methylergonovine) * Antipsychotics (e.g., pimozide or clozapine) * Erectile dysfunction agents (e.g., sildenafil, tadalafil, or vardenafil) * Antiarrhythmics (e.g., bepridil, flecainide, lidocaine, mexiletine, amiodarone, quinidine, or propafenone) * Immune modulators (e.g., cyclosporine, tacrolimus, or sirolimus) * Miscellaneous drugs (e.g., theophylline, quetiapine, risperidone, tacrine, or atomoxetine) * No other concurrent anticancer agents or therapies * No concurrent medications that are associated with a risk of QTc prolongation and/or Torsades de Pointes