Inclusion Criteria

DISEASE CHARACTERISTICS:

- One of the following diagnoses:

- Chronic myelogenous leukemia in lymphoid blast crisis

- Acute lymphoblastic leukemia (ALL) that is in first relapse or failed induction

- No more than 1 prior course of induction chemotherapy

- Philadelphia chromosome-positive (Ph+) by cytogenetic analysis OR bcr/abl
translocation by fluorescent in situ hybridization

- At least 30% blasts in bone marrow

- Ineligible for or refused allogeneic stem cell transplantation

- Not previously treated with imatinib mesylate OR currently receiving imatinib
mesylate with stable disease on 2 bone marrow biopsies at least 2 weeks apart

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- ECOG 0-2

Life expectancy:

- Not specified

Hematopoietic:

- See Disease Characteristics

Hepatic:

- Bilirubin less than 3 times upper limit of normal (ULN)

- ALT and AST less than 3 times ULN

Renal:

- Creatinine less than 2 times ULN

Cardiovascular:

- No New York Heart Association class III or IV cardiac disease

Other:

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective barrier contraception during and for at least 2
weeks after study for female patients and at least 3 months after study for male
patients

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- See Disease Characteristics

- No prior allogeneic bone marrow or peripheral blood stem cell transplantation

- At least 48 hours since prior interferon alfa

Chemotherapy:

- See Disease Characteristics

- At least 24 hours since prior hydroxyurea

- At least 6 weeks since prior busulfan

- Concurrent hydroxyurea or anagrelide for severe leukocytosis or thrombocytosis
allowed

Endocrine therapy:

- Not specified

Radiotherapy:

- Not specified

Surgery:

- Not specified

Other:

- No prior therapy for blast crisis except hydroxyurea

- No prior salvage or reinduction therapy for Ph+ ALL

- At least 4 weeks since other prior investigational agents