RATIONALE: Imatinib mesylate may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Giving imatinib mesylate after a donor stem cell transplant may prevent the recurrence of Philadelphia chromosome-positive leukemia.

PURPOSE: This phase I/II trial is studying the side effects of giving imatinib mesylate after a donor stem cell transplant and to see how well it works in treating patients with Philadelphia chromosome-positive leukemia.

OBJECTIVES:

Primary

• Determine the safety of adjuvant imatinib mesylate after allogeneic hematopoietic stem cell transplantation (AHSCT) in patients with high-risk Philadelphia chromosome-positive leukemia.

Secondary

• Determine the bcr/abl transcript load during the first 90 days after AHSCT in patients treated with this drug from the time of engraftment.
• Determine the 1-year survival of patients treated with this drug.

OUTLINE: This is an open-label, pilot, multicenter study.

Beginning within 14-30 days after allogeneic stem cell transplantation, patients receive oral imatinib mesylate once daily until 1 year after transplantation. Treatment continues in the absence of unacceptable toxicity or disease progression.

Patients are followed for survival.

PROJECTED ACCRUAL: A total of 20 patients will be accrued for this study.

DISEASE CHARACTERISTICS:

• Diagnosis of 1 of the following:

  • Acute lymphoblastic leukemia or chronic myeloid leukemia (CML) characterized by p^190 and/or p^210 bcr/abl gene rearrangement
  • Accelerated or blastic phase CML
  • CML in second or greater chronic phase

• No imatinib mesylate-resistant leukemia

• Planned allogeneic hematopoietic stem cell transplantation

  • Availability of an appropriately matched related or unrelated donor
  • Autologous or nonmyeloablative transplantation is not allowed

• None of the following within 4 days after the date of neutrophil engraftment*:

  • More than 5% marrow blasts
  • Circulating peripheral blood leukemic blasts
  • Aberrant antigen expression on marrow myeloblasts ≥ 1% by multidimensional flow cytometric assay
  • Presence of bcr/abl in > 5% of marrow interphase nuclei by fluorescent in situ hybridization
  • More than 1 of 20 Philadelphia chromosome-positive marrow metaphases
  • CNS involvement by leukemia NOTE: *The date of neutrophil engraftment is defined as the second consecutive day at which the peripheral blood absolute neutrophil count exceeds 500/mm3

PATIENT CHARACTERISTICS:

Performance status

• Not specified

Life expectancy

• At least 2 months

Hematopoietic

• See Disease Characteristics
• Absolute neutrophil count ≥ 1,200/mm^3 (use of filgrastim [G-CSF] allowed)

Hepatic

• Not specified

Renal

• Not specified

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No known imatinib mesylate hypersensitivity
• No other disease that severely limits life expectancy

PRIOR CONCURRENT THERAPY:

Biologic therapy

• See Disease Characteristics