AFR10 - Combination Therapy of Imatinib Mesylate (IM) + Alpha-2A Interferon for Chronic Phase CML Patients Resistant or Refractory to IM Used as Single Therapy for at Least One Year

Inclusion Criteria: * Chronic phase Philadelphia positive CML, confirmed by karyotyping (or FISH) analysis, in complete hematologic response with IM. * Lack of major cytogenetic response after at least one year of STI 571 as single therapy. * Male and female \* 18 years old. * Informed consent signed up. * Performance status grade 0 - 2 (ECOG). * SGOT and SGPT \<3N * Serum bilirubin \< 1.5 N * Serum creatinine \< 1.5 N * No HSC graft planned * B-HCG negative for female with potential childbearing Exclusion Criteria: * Absence of complete hematologic response * Extramedullar involvement * Previous extra-hematologic intolerance of Interféron at a dose superior or equal to 25 MUI/week * Depressive syndrome not controlled * Not controlled dysthyroidy * Auto-immune pathology not controlled * Women with childbearing potential who are unwilling or unable to use an adequate method to avoid pregnancy for the entire period of the study * Significant cardiac disease (grade 3 or more) * Known seropositivity for HIV * Active viral hepatitis * Other malignant disease * Other experimental medication