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