Sorafenib Maintenance Therapy for Patients With AML After Allogeneic Stem Cell Transplant

Inclusion Criteria: * Subjects with AML with the FLT3-ITD mutation who have undergone allogeneic HSCT * Peripheral blood chimerism studies showing \>/= 70% of all cells are of donor origin * Adequate hematologic and hepatic function * ECOG performance status 0-2 * Able to swallow whole pills Exclusion Criteria: * Evidence of relapsed/recurrent/residual disease as assessed by bone marrow aspirate and biopsy performed between days 30-60 after HSCT * Active acute graft vs host disease requiring an equivalent dose of \> 0.5 mg/kg/day of prednisone or equivalent or those patients which necessitated the addition of another agent for the treatment of GVHD beyond corticosteroids * Ongoing uncontrolled infection * Cardiac disease: congestive heart failure \> class II NYHA, unstable angina or new onset angina (began within the last 3 months) or myocardial infarction within the past 6 months * Cardiac ventricular arrhythmias requiring anti-arrhythmic therapy * Uncontrolled hypertension * Known HIV infection or chronic hepatitis B or C * Thrombotic or embolic events such as cerebrovascular accident including transient ischemic attacks within the past 6 months * Pulmonary hemorrhage/bleeding event \> CTCAE v 4.0 Grade 2 within 4 weeks of starting study drug * Any other hemorrhage/bleeding event \> CTCAE v. 4.0 Grade 3 within 4 weeks of starting study drug * Serious non-healing wound, non-healing ulcer, or bone fracture * Evidence or history of bleeding diathesis or coagulopathy * Major surgery or significant traumatic injury within 4 weeks of starting study drug * Use of St. John's Wort or rifampin (rifampicin) * Known or suspected allergy to sorafenib * Pregnant or breast-feeding * Receiving any other investigational agents