Inclusion Criteria:

1. Patients with newly-diagnosed chronic-phase Ph-positive chronic myeloid leukaemia (maximum 3 months as of the diagnosis of the disease, with the date of the cytogenetic study regarded as such).
2. Age between 18 and 72 years (both included).
3. Performance status < 2 on the ECOG scale (see Annex 3).
4. Secure written or oral informed consent in the presence of a witness and consent for biological samples (annexes 5 and 6).

Exclusion Criteria:

1. Criteria of acceleration or blastic crisis (see Annex 7).
2. When there is a compatible family donor in patients aged under 40 years or a non-relative donor in patients aged under 30 years (in whom allogenic transplant is still regarded as first-line treatment), the possibility of performing an allogenic transplant as first therapeutic option should be considered. In any case, as this aspect is still a matter of debate, it is left up to each group to take the relevant decision depending on the institution's policy.
3. Administration of other treatments before inclusion in the protocol (a maximum of 3 months of monotherapy with hydroxyurea is permitted).
4. Altered hepatic or renal function (SGOT, SGPT, total bilirubin and creatinine > 1.5 times the upper limit of normality).
5. Uncontrolled diseases, such as thyroidal dysfunction, diabetes mellitus, angina pectoralis, serious heart failure (functional class III/IV of the New York Heart Association classification), neuropsychiatric infection or disease (see annex 15).
6. Positive serology for HIV.
7. Record of cancer in the last 5 years (barring basal cell skin carcinoma and cervical carcinoma in situ).
8. Pregnancy or breastfeeding