Objectives:

1. To achieve (molecular CR) after 12 months of Imatinib (PEG-IFN) and GM-CSF.
2. To increase the proportion of patients achieving a complete cytogenetic response.
3. To evaluate the durations of PCR negativity, cytogenetic response, hematologic control, and survival.
4. To analyze differences in response rates and in prognosis within different risk groups and patient characteristics.

Inclusion Criteria:

• Patients with a diagnosis of Ph-positive or Bcr-positive CML in early chronic phase CML (i.e., time from diagnosis 12 months). Except for hydroxyurea, patients must have received no or minimal prior therapy, defined as <1 month of prior IFN-a (with or without ara-C) and/or Gleevec.
• Age => 18 years
• ECOG performance of 0-2.
• Adequate end organ function, defined as the following: total bilirubin <1.5x ULN, SGPT <2.5x ULN, creatinine <1.5x ULN.
• Patients must sign an informed consent indicating they are aware of the investigational nature of this study, in keeping with the policies of the hospital.

Exclusion Criteria:

• NYHA cardiac class 3-4 heart disease
• Patients with active, uncontrolled psychiatric disorders including: psychosis, major depression, and bipolar disorders.
• Female patients of childbearing potential must have negative pregnancy test within 7 days before initiation of study drug dosing. Postmenopausal women must be amenorrheic for at least 12 months to be considered of non-childbearing potential. Male and female patients of reproductive potential must agree to employ an effective method of birth control throughout the study and for up to 3 months following discontinuation of study drug.
• Patients in late chronic phase (i.e., time from diagnosis to treatment >12 months), accelerated phase or blastic phase are excluded.

The definitions of CML phases are as follows:

1. Early chronic phase: time from diagnosis to therapy < 12 months Late chronic phase: time from diagnosis to therapy > 12 months
2. Blastic phase: presence of 30% blasts or more in the peripheral blood or bone marrow.

3. Accelerated phase CML: presence of any of the following features:

   • Peripheral or marrow blasts 15% or more
   • Peripheral or marrow basophils 20% or more
   • Thrombocytopenia < 100 x 109/L unrelated to therapy
   • Documented extramedullary blastic disease outside liver or spleen due to past causes
   • Clonal evolution defined as the presence of additional chromosomal abnormalities other than the Ph chromosome is part of accelerated phase CML. Ph chromosome variants or complex Ph chromosome translocations are not considered to indicate disease acceleration. We have recently found clonal evolution to have a variable prognostic impact and may be suppressed with IFN-a therapy. Hence these patients will be eligible if no other signs of accelerated phase are present, and analyzed separately.