Long term survival data still lacks after imatinib. However, it has been already shown that the disease phase influences the efficacy of imatinib in CML: responses (HR and particularly CgR) are better in CP versus accelerated and blastic phase. Results in CP are better in patients treated early after the onset of the disease with respect to late CP . To date, the early McR rate to imatinib is clearly higher in low and intermediate risk versus high risk (88 and 84% versus 65%).