To assess the efficacy of inecalcitol in combination with imatinib in CML patients with molecular residual disease on imatinib monotherapy.

To determine:

• Duration of response
• Progression free survival
• Proportion of responders 2 years after discontinuation of inecalcitol
• Duration of response after discontinuation of inecalcitol and imatinib
• Bone remodelling effect
• Safety of inecalcitol in combination with imatinib
• Quality of Life

Inclusion Criteria:

• Men or women aged of at least 18 years at the time of informed consent signature;
• Patients have signed written informed consent;
• ECOG performance status < 2;
• Patients with Philadelphia chromosome positive chronic phase CML and M BCR-ABL transcript positivity (e13a2 or e14a2);
• Treatment with imatinib for more than 2 years (a history of treatment with interferon is tolerated);
• Patient in complete cytogenetic response with BCR-ABL/ABL status between 0.1% International Scale (IS) and 0.01% IS and no BCR-ABL checkpoint in the last six months better than Molecular Response MR4 ( i.e. BCR-ABL ratio < 0.01% IS);
• Women of child bearing potential have a negative pregnancy test prior to first dose and agree to practice effective contraception during the study;
• Fertile men agree to practice effective contraception during the study;
• Patients agree to comply with the study requirements and agree to come to the clinic for required study visits;
• Patients agree to follow medication restrictions during the study;

Exclusion Criteria:

• Expression of unusual BCR-ABL transcripts (other than e13a2 or e14a2);
• Pregnant or lactating women;
• Participating in another clinical trial with any investigative drug within 30 days prior to study enrolment(except for OPTIM imatinib);
• Treatment with interferon within the last 24 months;
• Imatinib dose modification within the last 3 months;
• Prior history of haematopoietic stem cell transplantation;
• Impaired renal function with creatinine clearance < 30 ml/min/1.73m² according to the MDRD formula;
• Hypercalcemia (corrected with albuminemia);
• History of diseases known to be associated with calcium disorders: ongoing hyperparathyroidism, sarcoidosis….;
• Presence or history of symptomatic kidney stones in the last 5 years;
• Current use of drugs known to influence serum calcium (such as thiazide diuretics, teriparatide, calcitonin and multivitamin supplements containing > 400 IU of vitamin D or calcium);
• Current use of digitalis;
• Current use of drugs which could influence bioavailability of inecalcitol (such as magnesium-containing antacids, bile-resin binders);
• Patients with a chronic condition which is not well controlled that, according to the investigator, would interfere with the completion of the study;
• Use of any other experimental drug, therapy or vitamin D supplementation within 30 days of first inecalcitol administration;
• Patients with a mental deficiency preventing proper understanding of trial protocol requirements;