Inclusion Criteria:

          -  Age ≥ 18

          -  CMML diagnosis according to WHO criteria Stable excess in blood monocytes, > 1 G/L
             Lack of bcr-abl rearrangement (or Philadelphia chromosome) Bone marrow blast cells <
             20% Dysplasia of at least one lineage or clonality marker or blood monocytosis during
             more than 3 months w/o other explanation Blood and marrow smears will be reviewed at
             each country's level, but morphologist meetings at the 3 country level are planned for
             better harmonization and review of difficult cases

          -  WBC ≥ 13 G/L Measured on two successive CBC at least two weeks apart, outside of a
             context of infection.

          -  Either D1 or D2

        D1: At least two of the following criteria, reviewed at each country's level: (modified
        from Wattel et al. Blood 1996) Marrow blasts >= 5 % Clonal cytogenetic abnormality (other
        than t(5;12) (q33; p13) and isolated loss of Y chromosome ) Anemia (Hb < 10 g/dL) ANC > 16
        G/l (in absence of infection) Thrombocytopenia (platelet count < 100 G/L) Splenomegaly > 5
        cm below costal margin (spleen size should also be measured by an imaging technique)

        Or:

        D2: Extramedullary involvement: Including documented cutaneous, pleural or pericardial
        effusion.

          -  No prior treatment (except supportive care, or ESA, or short term (< 6 weeks) HY in
             patients presenting with high WBC counts)

          -  Performance status 0-2 on the Eastern Cooperative Oncology Group (ECOG) Scale.

          -  Adequate organ function including the following Hepatic : total bilirubin < 1.5 times
             upper limit of normal (ULN) (except moderate unconjugated hyperbilirubinemia due to
             intra medullary hemolysis or Gilbert syndrome) , alanine transaminase (ALT) and
             aspartate transaminase (AST) < 3xULN Renal : serum creatinine < 2 x ULN

          -  Signed Informed consent

          -  Negative pregnancy and adequate contraception (including in male patients wishing to
             father) if relevant.

        Exclusion Criteria:

          -  Myeloproliferative / myelodysplastic syndrome other than CMML

          -  CMML with t(5 ;12) or PDGFBR rearrangement that may receive imatinib

          -  Patients eligible for allogeneic bone marrow transplantation with an identified donor

          -  Pregnant or breastfeeding

          -  Performance status > 2 on the ECOG Scale.

          -  Serious concomitant systemic disorder, including active bacterial, fungal or viral
             infection that in the opinion of the investigator would compromise the safety of the
             patient and/or his/her ability to complete the study

          -  Prior malignancy (except in situ cervix carcinoma, limited basal cell carcinoma, or
             other tumors if not active during the last 3 years)