Granulocyte-colony Stimulating Factor (G-CSF) and Plerixafor Plus Sorafenib for Acute Myelogenous Leukemia (AML) With FLT3 Mutations

Inclusion Criteria:

1. Patients will be 18 years of age or older.
2. Patients must have relapsed/refractory leukemia with FLT3 (ITD) mutations. Patients with AML FLT3 mutations who are not eligible for frontline standard therapy, or who refuse to be treated with intensive chemotherapy, may be eligible.
3. Serum biochemical values with the following limits unless considered due to leukemia: creatinine \</= 1.5 mg/dl; total bilirubin \</= 1.5 mg/dL, unless increase is due to hemolysis or congenital disorder; or transaminases (SGPT) \</= 2.5 x upper limit of normal (ULN)
4. Able to take oral medication.
5. Able to understand and provide signed informed consent.
6. Ejection fraction at screening must be \>/=50%.
7. Performance status \< 3, unless directly related to leukemic disease process as determined by the Principal Investigator.

Exclusion Criteria:

1. Subjects with acute promyelocytic leukemia.
2. Patients with absolute blast count \> 20 k/uL.
3. Nursing women, women of childbearing potential with positive urine pregnancy test, or women of childbearing potential who are not willing to maintain adequate contraception (such as birth control pills, intrauterine device (IUD), diaphragm, abstinence, or condoms by their partner) over the entire course of the study.
4. Men not willing to maintain adequate contraception with their partner over the entire course of the study.
5. Hypertension \> 140 mmHg systolic OR \> 90 mmHg diastolic with or without antihypertensive therapy.
6. Cardiac disease: Congestive heart failure \> class II New York Heart Association (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.
7. Cardiac ventricular arrhythmias requiring anti-arrhythmic therapy. Sorafenib is contraindicated in patients with known severe hypersensitivity to sorafenib or any of the excipients.
8. Known human immunodeficiency virus (HIV) infection or active Hepatitis B or C.
9. Thrombotic or embolic events such as a cerebrovascular accident including transient ischemic attacks within the past 6 months.
10. Pulmonary hemorrhage/bleeding event \>/= CTCAE Grade 2 within 4 weeks of first dose of study drug.
11. Any other hemorrhage/bleeding event \>/= CTCAE Grade 3 within 4 weeks of first dose of study drug.
12. Major surgery, open biopsy or significant traumatic injury within 4 weeks of first study drug.
13. Currently using St. John's Wort or rifampin.
14. Known or suspected allergy to sorafenib or any agent given in the course of this trial.
15. Active clinically serious and uncontrolled infection \> CTCAE Grade 2.
16. Serious non-healing wound, ulcer, or bone fracture.
17. Patients currently receiving any other standard or investigational treatment for their hematologic malignancy.