The Use of Decitabine as Induction Therapy for Acute Myeloid Leukemia With Complex and/or Monosomal Karyotype

Acute myeloid leukemia (AML) is a heterogeneous group of diseases with distinct clinicopathologic features sharing in common an abnormal increase in myeloblasts in blood and bone marrow (BM). In about 5-10% patients, the myeloblasts exhibit chromosomal abnormalities (complex and/or monosomal karyotype, CK/MK\*) that are associated with refractoriness to conventional chemotherapy and an extremely bad prognosis. Standard induction chemotherapy for AML comprises daunorubicin and cytarabine, the "7+3" regimen. However, treatment is largely ineffective for CK/MK AML with a temporary clearance of blasts achieved in only 30-40% cases and the cumulative toxicities resulting from repeated courses of chemotherapy have significantly increased the morbidity and mortality risks in subsequent allogeneic BMT. Therefore, standard treatment is unsatisfactory and there is an unmet clinical need for more effective and less toxic induction regimen. Both previous and recent studies showed that 10 day course of decitabine (20 mg/m2/day) induced remission in 70-100% patients with CK/MK AML, particularly those with TP53 mutations. In this study, patients with CK/MK AML will be treated with decitabine to induce remission. Bone marrow examination will be performed after each course until complete clearance of blasts or disease progression. Patients achieving CR/CRi (see below) will continue to receive 4 more courses, after which patients eligible for BMT and for whom donors are available will receive curative BMT. We reckon that the time it takes for 4 courses of decitabine will suffice for transplantation workup in HK. . Patients ineligible for BMT will continue to receive decitabine until leukemia progression. The response rate, leukemia free survival (LFS), overall survival (OS) and percentage of patients who can be bridged to BMT will be compared with historical 7+3 regimen control.