Low-Dose Daunorubicin in Relapsed/Refractory Acute Leukemia

Disease relapse remains the primary challenge in the treatment of acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL). There is no standard of care treatment option for relapsed acute leukemia, and investigational therapies are recommended. Clinically targeting the leukemia stem cell (LSC) remains an unmet need in both AML and ALL. Therefore, a primary objective of this trial is to determine the molecular pharmacodynamic effects of low dose daunorubicin (DNR) on beta-catenin phosphorylation in serial bone marrow samples of patients with relapsed leukemia. Prior to studying low-dose DNR in complex, multi-agent regimens, it is essential to confirm that it inhibits p-beta-catenin S552 in humans. This pilot study is designed to assess the feasibility and tolerability of low dose DNR administration to patients with relapsed/refractory AML and ALL, and obtain preliminary data regarding target engagement. A second objective is to demonstrate the safety and feasibility of low-dose daunorubicin administration in patients with relapsed/refractory acute leukemia. Beta-catenin phosphorylation will be measured by immunohistochemistry assay in bone marrow samples taken from patients at study entry and at Day 8 following study therapy with low-dose DNR. The investigators will also measure the pharmacokinetics of low dose DNR in these patients, to enable preliminary PK-PD analyses and because there are essentially no PK data for DNR at comparable doses using modern analytical methodologies. Following participation on this brief pharmacodynamic proof-of-concept trial, patients can then proceed to other conventional or investigational therapies, as clinically indicated.