A Phase III Randomized, Double-blind, Controlled Study Comparing Clofarabine and Cytarabine Versus Cytarabine Alone in Adult Patients 55 Years and Older With Acute Myelogenous Leukemia (AML) Who Have Relapsed or Are Refractory After Receiving up to Two Prior Induction Regimens

Clofarabine (injection) is approved by the Food and Drug Administration (FDA) for the
treatment of pediatric patients 1 to 21 years old with relapsed acute or refractory
lymphoblastic leukemia (ALL) who have had at least 2 prior treatment regimens.

There is no recommended standard treatment for relapsed or refractory acute myelogenous
leukemia in older patients. Cytarabine is the most commonly used drug to treat these
patients. This study will determine if there is benefit by combining clofarabine with
cytarabine. Patients will be randomized to receive up to 3 cycles of treatment with either
placebo in combination with cytarabine or clofarabine in combination with cytarabine.
Randomization was stratified by remission status following the first induction regimen (no
remission [i.e., CR1 = refractory] or remission <6 months vs CR1 = remission ≥6 months). CR1
is defined as remission after first pre-study induction regimen. The safety and tolerability
of clofarabine in combination with cytarabine and cytarabine alone will be monitored
throughout the study.