Sunitinib in Treating Patients With Myelodysplastic Syndromes or Chronic Myelomonocytic Leukemia

Inclusion Criteria:

* MDS syndromes meeting 1 of the following: Intermediate-2 disease, high-risk disease (IPSS score\>=1.5)
* CMML: WBC\>12,000/mm\^3, Intermediate-2 disease with WBC=\<12,000/mm\^3, high-risk disease (IPSS score\>=1.5) with WBC=\<12,000/mm\^3
* Patients with insufficient/inadequate metaphases for cytogenetic analysis are eligible if bone marrow blasts are \>10% and/or 2-3 cytopenias are present
* No known brain metastases
* Life expectancy\>12 weeks
* ECOG PS 0-2/Karnofsky PS 60-100%
* Calcium=\<3.0 mmol/L
* Bilirubin normal
* AST and ALT=\<2.5 times upper limit of normal
* Creatinine normal/creatinine clearance\>=60 mL/min

Exclusion Criteria:

* No history of significant ECG abnormalities including but not limited to: ventricular arrhythmias (ventricular tachycardia, ventricular fibrillation\>=3 beats in a row); QTc prolongation (i.e.QTc interval\>=500msec)
* No history of allergic reaction to compounds of similar chemical/biological composition to sunitinib malate
* No NYHA class III-IV congestive heart failure
* Patients with history of NYHA class II congestive heart failure who are asymptomatic on treatment are eligible
* No abdominal fistula/G perforation/intraabdominal abscess within past 28 days
* No serious cardiovascular disease within past 12 months including: cerebrovascular accident or transient ischemic attack, myocardial infarction, cardiac arrhythmia, stable or unstable angina, symptomatic congestive heart failure, coronary or peripheral artery bypass graft or stenting
* No pulmonary embolism within past 12 months
* No uncontrolled hypertension (systolic BP\>=140 mmHg/diastolic BP\>=90 mmHg)
* No condition impairing ability to swallow/retain sunitinib malate tablets including: GI tract disease resulting in inability to take oral medication, requirement for IV alimentation, prior surgical procedures affecting absorption, active peptic ulcer disease
* No serious/nonhealing wound, ulcer, or bone fracture
* No uncontrolled pre-existing thyroid abnormality
* No concurrent uncontrolled illness including ongoing/active infection
* No psychiatric illness/social situation that would preclude study participation
* Not pregnant/nursing
* Negative pregnancy test
* Fertile patients must use effective barrier contraception
* 4 weeks since prior major surgery
* Prior central thoracic radiotherapy that included heart in radiotherapy port allowed provided NYHA congestive heart failure=\<class II
* Prior anthracycline exposure allowed provided NYHA congestive heart failure=\<class II
* No other prior therapy for MDS/CMML except epoetin alfa, darbepoetin alfa, filgrastim or sargramostim
* At least 2 weeks since prior epoetin alfa
* At least 4 weeks since prior darbepoetin alfa
* No other prior antiangiogenic agents including but not limited to: bevacizumab, sorafenib tosylate, pazopanib hydrochloride, AZD2171, vatalanib, VEGF Trap
* More than 7 days since prior and no concurrent potent CYP3A4 inhibitors
* More than 12 days since prior and no concurrent potent CYP3A4 inducers including: Rifampin, Rifabutin, Carbamazepine, Phenobarbital, Phenytoin, Hypericum perforatum, Efavirenz, Tipranavir
* No concurrent birth control patch/oral birth control pills/depot/injectable birth control methods
* No concurrent therapeutic coumarin-derivative anticoagulants
* Low dose(=\<2mg) warfarin for prophylaxis of thrombosis allowed
* Low molecular weight heparin allowed if INR=\<1.5
* No concurrent agents with proarrhythmic potential including: Terfenadine, Quinidine, Procainamide, Disopyramide, Sotalol, Probucol, Bepridil, Haloperidol, Risperidone, Indapamide, Flecainide acetate
* No concurrent combination antiretroviral therapy for HIV-positive patients
* No other concurrent investigational agents