Clofarabine and Cyclophosphamide Combination in Acute Lymphoblastic Leukemia Patients

Inclusion Criteria:

1. Previously treated ALL (including Burkitt's lymphoma and lymphoblastic lymphoma) in relapse or primary refractory. For patients in first relapse, the first remission duration may not exceed 12 months.
2. Age \>/= 21 years.
3. Zubrod performance status \</= 3.
4. Adequate liver function (bilirubin \</= 2.5 mg/dL and Serum glutamic pyruvic transaminase (SGPT or SGOT) \</= 3 \* ULN, unless considered due to tumor), and renal function (glomerular filtration rate \[GFR\] \>/= 60 mL/min). Even if organ function abnormalities are considered due to tumor, the upper limit for bilirubin is \</= 5 mg/dL and creatinine \</= 3 mg/dL.
5. Male and female patients who are fertile agree to use an effective barrier method of birth control (e.g., latex condom, diaphragm, cervical cap, etc.) to avoid pregnancy. Female patients need a negative serum or urine pregnancy test within 14 days of study enrollment (applies only if patient is of childbearing potential. Non-childbearing is defined as \>/= 1 year postmenopausal or surgically sterilized).

Exclusion Criteria:

1. Patients with active heart disease (New York Heart Association (NYHA) class \>/= 3 as assessed by history and physical examination).
2. Patients with a cardiac ejection fraction (as measured by either Multi Gated Acquisition Scan (MUGA) or echocardiogram) \< 45% are excluded.
3. Patients who receive other chemotherapy. Patients must have been off previous therapy for \>/= 2 weeks and must have recovered from acute toxicity of all previous therapy prior to enrollment. (Concurrent therapy for central nervous system (CNS) prophylaxis or treatment for CNS relapse is permitted). Treatment may start earlier if necessitated by the patient's medical condition following discussion with the Principal Investigator.
4. Pregnant and breast-feeding patients are excluded