A Phase I Study of CLAG Regimen in Combination With Imatinib Mesylate (Gleevec) in Refractory or Relapsed Leukemias

OBJECTIVES:

• Determine the safety and feasibility of cladribine, cytarabine, and imatinib mesylate in patients with refractory or relapsed acute myeloid leukemia or blastic phase chronic myelogenous leukemia.
• Determine the maximum tolerated dose of imatinib mesylate in patients treated with this regimen.
• Correlate the expression of c-kit and the presence of c-kit mutations with clinical response in patients treated with this regimen.
• Correlate the in vitro inhibitory effects of imatinib mesylate and cytarabine on the proliferation and survival of leukemic cells with clinical response in patients treated with this regimen.

OUTLINE: This is a dose-escalation study of imatinib mesylate.

Patients receive oral imatinib mesylate once daily on days 1-15 and cladribine IV over 2 hours and cytarabine IV over 4 hours on days 3-7. Patients also receive filgrastim (G-CSF) subcutaneously on days 2-7. Treatment repeats every 15 days for 2 courses in the absence of disease progression or unacceptable toxicity.

Cohorts of 3-6 patients receive escalating doses of imatinib mesylate until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience dose-limiting toxicity.