This is an open label randomized controlled phase II study of AS1411 combined with Cytarabine in the treatment of patients with primary refractory or relapsed acute myeloid leukemia.

Inclusion Criteria:

• Diagnosis of AML as defined by the World Health Organization (WHO) classification (Vardiman 2009)
• Primary refractory AML (defined as a failure to achieve a CR or CRi after therapy with curative intent) or AML in first relapse
• ECOG Performance status 0, 1 or 2
• Age > 18 and < 70 years
• For patients presenting with primary refractory AML, > 20% blasts on baseline bone marrow assessment
• For patients presenting with relapsed AML, > 5% blasts on baseline bone marrow assessment

Exclusion Criteria:

• An initial diagnosis of acute promyelocytic leukemia (as defined by French-American-British criteria (Bennett 1976))
• Secondary AML, defined as AML evolving from antecedent hematological disorder or prior exposure to leukemogenic therapy or agent
• Clinically active CNS leukemia
• Previously received a total cumulative dose of cytarabine > 6g/m2 in the last 6 months
• Previously received > 1 induction regimen (Defined as 1 or 2 cycles of a drug or a drug combination administered as remission induction therapy)