A Study of Clofarabine and Cytarabine for Older Patients With Relapsed or Refractory Acute Myelogenous Leukemia (AML)(CLASSIC I)

Inclusion Criteria:

Have a diagnosis of Acute Myelogenous Leukemia (AML) according to World Health Organization (WHO) classification
Relapsed after receiving up to 2 prior induction regimens (i.e. first or second relapse)or are refractory to not more than one prior combination chemotherapy induction regimen
Be ≥ 55 years of age
Have an Eastern Cooperative Oncology Group (ECOG) score of 0-2
Be able to comply with study procedures and follow-up examinations
Be nonfertile or agree to use birth control during the study through the end of treatment visit and for at least 90 days after the last dose of study drug
Have adequate liver and renal function as indicated by certain laboratory values

Exclusion Criteria:

Received previous treatment with clofarabine
Received bolus, intermediate or high-dose cytarabine as induction therapy unless certain remission criteria are met
Have received a hematopoietic stem cell transplant (HSCT) within the previous 3 months
Have moderate or severe graft versus host disease (GVHD), whether acute or chronic
Are receiving any other chemotherapy or investigational therapy. Patients must have been off prior AML therapy for at least 2-6 weeks prior to entering study.
Have a psychiatric disorder that would interfere with consent, study participation, or follow-up
Have an active, uncontrolled infection
Have any other severe concurrent disease, or have a history of serious organ dysfunction or disease involving the heart, kidney, liver, or other organ system
Have been diagnosed with another malignancy, unless disease-free for at least 5 years; patients with treated nonmelanoma skin cancer, in situ carcinoma, or cervical intraepithelial neoplasia, regardless of the disease-free duration, are eligible for this study if definitive treatment for the condition has been completed; patients with organ-confined prostate cancer with no evidence of recurrent or progressive disease are eligible if hormonal therapy has been initiated or the malignancy has been surgically removed.
Have clinical evidence suggestive of central nervous system (CNS) involvement with leukemia unless lumbar puncture confirms absence of leukemic blasts in the cerebrospinal fluid(CSF)
Known HIV positivity
Are pregnant or lactating