Study of Treatment Free Remission in Patients With Chronic Myeloid Leukemia in Chronic Phase

Inclusion criteria: 1. Signed Informed consent. 2. Patients with a diagnosis of CML BCR-ABL positive in CP treated with approved TKI (Imatinib, Nilotinib or Dasatinib) in 1st line or in 2nd line due to intolerance to the 1st line or in 2nd line due to the lack of deep MR with 1st line TKI, which never presented criteria for treatment failure. 3. Age ≥ 18 years 4. ≥ 4 years of treatment with imatinib, nilotinib or dasatinib. 5. Achievement of MR 4.5 in a standardized laboratory (BCR-ABL1 IS ≤ 0.0032%). 6. Evidence of MR 4.5 sustained for ≥ 2 years, as documented in at least 4 tests performed at least 3 months apart. 7. Evidence of typical quantifiable BCR-ABL1 transcript (b3a2 \[e14a2\] and / or b2a2 \[e13a2\], typical isoforms of p210). Exclusion criteria: 1. Patients who previously discontinued TKI and demonstrated recurrence of the disease. 2. Patients with failure to any TKI at any time. 3. Patients who presented accelerated phase or CML in blast crisis at any time. 4. Patients with atypical transcript not quantifiable by RT qPCR 5. BCR-ABL mutation detected at any time during the course of the resistant disease