Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed chronic myelogenous leukemia (CML)

- In chronic phase

- Philadelphia chromosome (Ph)-positive

- No accelerated or blastic phase

- Accelerated phase CML is defined as ≥ 15% but < 30% blasts in peripheral
blood or bone marrow OR ≥ 30% blasts and promyelocytes in peripheral blood
or bone marrow provided that < 30% blasts were present OR ≥ 20% peripheral
basophils OR platelet count < 100,000/mm^3, unrelated to therapy

- No less than 20 metaphases in the bone marrow sample

- No evidence of complete cytogenetic response to imatinib mesylate (complete
cytogenetic response defined as 0% Ph-positive cells in bone marrow)

- Receiving continuous imatinib mesylate therapy for ≥ the past 9 months

- Dosage ≥ 600 mg/day for ≥ the past 3 months

- Stable dose of 600 mg/day for ≥ the past 4 weeks

- Achieved and maintained hematological response to imatinib mesylate as defined by all
of the following:

- WBC < 20,000/mm^3

- Basophils < 20%

- Less than 5% myelocytes and metamyelocytes in peripheral blood

- No blasts or promyelocytes in peripheral blood

- No evidence of disease-related symptoms or extramedullary disease, including
enlarged spleen or liver

PATIENT CHARACTERISTICS:

Age

- 18 and over

Performance status

- WHO 0-2

Life expectancy

- Not specified

Hematopoietic

- See Disease Characteristics

- Absolute neutrophil count ≥ 1,500/mm^3

- Platelet count ≥ 100,000/mm^3

- Hemoglobin ≥ 9 g/dL

Hepatic

- AST and ALT < 1.5 times upper limit of normal (ULN)

- Bilirubin < 1.5 times ULN (except for patients with Gilbert's disease)

- PTT < 1.5 times ULN (except for patients on oral anticoagulation therapy)

- INR < 1.5 times ULN (except for patients on oral anticoagulation therapy)

Renal

- Creatinine < 1.5 times ULN

Cardiovascular

- No angina

- 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 3 months
after study participation

- HIV negative

- No history of non-compliance with medical regimens

- No hypercholesterolemia or hypertriglyceridemia (fasting state) ≥ grade 2 (despite
lipid-lowering therapy)

- No diabetes mellitus

- No thyroid dysfunction

- No neuropsychiatric disorders

- No infection

- No other severe and/or uncontrolled medical condition that would preclude study
participation

- No other malignancy within the past 5 years except adequately treated basal cell or
squamous cell skin cancer or carcinoma in situ of the cervix

PRIOR CONCURRENT THERAPY:

Biologic therapy

- No prior allogeneic, syngeneic, or autologous bone marrow transplantation or stem
cell transplantation for CML

- No concurrent prophylactic hematopoietic growth factors (e.g., filgrastim [G-CSF],
sargramostim [GM-CSF], or epoetin alfa)

Chemotherapy

- No prior chemotherapy regimens used in transplantation

Endocrine therapy

- Not specified

Radiotherapy

- Not specified

Surgery

- Recovered from prior major surgery

Other

- No prior sirolimus in combination with imatinib mesylate

- At least 4 weeks since prior investigational agents used in combination with imatinib
mesylate and recovered

- No other concurrent investigational therapies

- No other concurrent anticancer agents