|Exclusion Criteria:||1) Nursing and pregnant females.|
2) Patients with acute promyelocytic leukemia are excluded unless multiply refractory and no other standard treatment strategies are available to them
3) Patients with known allergy to sorafenib or azacitidine, mannitol or any of their components.
4) Patients with known impairment of gastrointestinal (GI) function or GI disease that may significantly alter the absorption of sorafenib.
5) Patients with any other known disease (except carcinoma in-situ) or concurrent severe and/or uncontrolled medical condition (e.g. uncontrolled diabetes, cardiovascular disease including congestive heart failure, myocardial infarction within 6 months and poorly controlled hypertension, chronic renal disease (creatinine clearance < 20 ml/min using the Cockroft and Gault formula)., or active uncontrolled infection) which could compromise participation in the study.
6) Patients with a known confirmed diagnosis of HIV infection or active viral hepatitis (B or C).
7) Patients who have had any major surgical procedure within 28 days of Day 1.
8) Patients unwilling or unable to comply with the protocol.
9) Patients with known malignant disease of the central nervous system or advanced malignant hepatic tumors.
10) Cardiac disease: Congestive heart failure greater than class II NYHA. Patients must not have unstable angina (anginal symptoms at rest) or new onset angina (began within the last 3 months) or myocardial infarction within the past 6 months.
11) Cardiac ventricular arrhythmias requiring anti-arrhythmic therapy.
12) Uncontrolled hypertension defined as systolic blood pressure greater than 140 mmHg or diastolic pressure greater than 90 mmHg, despite optimal medical management.
13) Active clinically serious infection greater than CTCAE v4. Grade 2 not controlled with antibiotics.
14) Thrombolic or embolic events such as a cerebrovascular accident including transient ischemic attacks within the past 6 months.
15) Pulmonary hemorrhage/bleeding event greater than CTCAE v4. Grade 2 within 4 weeks of first dose of study drug.
16) Any other hemorrhage/bleeding event greater than CTCAE v4. Grade 3 within 4 weeks of first dose of study drug.
17) Serious non-healing wound, ulcer, or bone fracture.
18) Evidence or history of bleeding diathesis or coagulopathy
19) Known or suspected allergy to sorafenib or any agent given in the course of this trial.
20) Patients with a history of solid organ transplant
21) Patients with seizure disorder requiring medication (such as antiepileptics).
22) Use of strong CYP3A4 inducers (eg, St. John's wort, dexamethasone at a dose of greater than 16 mg daily, phenytoin, carbamazepine, rifabutin, phenobarbital, or rifampin within seven days of initiating dosing
23) Substance abuse, medical, psychological or social conditions that may interfere with the patient's participation in the study or evaluation of the study results