Safety and Efficacy of Ponatinib Followed by Imatinib in Patients With Chronic Myelogenous Leukemia in Chronic Phase

Inclusion Criteria: * Male or female patients aged ≥18 and ≤65 years at time of inform consent signature. * Cytologically confirmed CML, Philadelphia chromosome positive with or without additional chromosomal abnormalities and/or BCR-ABL positive (Major BCR (M-BCR) transcript exclusively), i. e. Cryptic Philadelphia chromosome patients can be enrolled: * diagnosed within the past 3 months prior to D1 (i.e. within 60 days \[± 7 days\] since the date of first cytogenetic analysis), * in chronic phase defined by i) \<15 % blasts in peripheral blood and bone marrow, ii) \< 30% blast plus promyelocytes in peripheral blood and bone marrow; iii) \< 20 % basophils in peripheral blood and iv) ≥100 X 109 platelets/L in peripheral blood, * no extra-medullary disease. * All EUTOS long-term survival Scores. * No prior treatment for CML with any tyrosine kinase inhibitor (eg. imatinib, dasatinib, nilotinib or bosutinib), or busulphan; interferon-alpha; homoharringtonine; cytosine arabinoside; or any other investigational agent; with the exception of hydroxyurea and/or anagrelide which are the only authorized prior treatments. Note: Hydroxyurea should be stopped at least 24 hours prior the initiation of ponatinib. * Eastern Cooperative Oncology Group performance status (ECOG PS) of 0, 1 or 2. * Adequate organ functions as defined below according to lab tests performed within 7 days before Day 1: Renal function: \- Serum creatinine clearance ≥ 50 mL/min/1.73m2 according to CKD-…