Effect of Imatinib Mesylate and the Pharmacokinetics of Acetaminophen/Paracetamol in Patients With Newly Diagnosed, Previously Untreated Chronic Myeloid Leukemia in Chronic Phase (CML-CP)

Inclusion criteria:

* Ability to provide written informed consent prior to participation to the study.
* Male or female patients ≥ 18 and ≤ 75 years of age
* Patients with CML-CP within 6 months of diagnosis (date of initial diagnosis is the date of first cytogenetic analysis). FISH analysis will not be accepted.
* Diagnosis of CML in chronic phase with cytogenetic confirmation of Philadelphia chromosome of (9;22) translocations and presence of Bcr-Abl
* Documented chronic phase CML as defined by:
* \< 15% blasts in peripheral blood and bone marrow
* \< 30% blasts plus promyelocytes in peripheral blood and bone marrow
* \< 20% basophils in the peripheral blood
* ≥ 100 x 109/L (≥ 100,000 /mm3) platelets
* No evidence of extramedullary leukemic involvement, with the exception of hepatosplenomegaly
* Adequate end organ function as defined by:
* total bilirubin \< 1.5 x ULN
* SGOT and SGPT \< 2.5 x UNL
* creatinine \< 1.5 x ULN
* Female patients of childbearing potential must have a negative serum pregnancy test within 7 days before initiation of study drug

Exclusion criteria:

* Patients in late chronic phase, accelerated phase, or blastic phase are excluded
* Patients who have received other investigational agents
* Patients who received imatinib for any duration prior to study entry
* Patient received any treatment for CML prior to study entry for longer than 2 weeks with the exception of hydroxyurea and/or anagrelide
* Patients with another primary malignancy except if the other primary malignancy is neither currently clinically significant or requiring active intervention
* Patients who are:
* pregnant
* breast feeding
* of childbearing potential without a negative pregnancy test prior to baseline
* male or female of childbearing potential unwilling to use barrier contraceptive precautions throughout the trial
* Post-menopausal women must be amenorrheic for at least 12 months to be considered of non-childbearing potential
* Patient with a severe or uncontrolled medical condition (i.e., uncontrolled diabetes, chronic renal disease)
* Patient previously received radiotherapy to ≥ 25% of the bone marrow
* Patient had major surgery within 4 weeks prior to study entry, or who have not recovered from prior major surgery
* Patients with an ECOG Performance Status Score ≥ 3
* Patients with International normalized ratio (INR) or partial thromboplastin time (PTT) \> 1.5 x IULN, with the exception of patients on treatment with oral anticoagulant
* Patients with known positivity for human immunodeficiency virus (HIV)
* baseline testing for HIV is not required
* Patients with any significant history of non-compliance to medical regimens or with inability to grant a reliable informed consent
* Patients with identified sibling donors where allogeneic bone marrow transplant is elected as first line treatment
* Patients who are chronic users of acetaminophen or medications containing acetaminophen.
* Patients who received acetaminophen or medications containing acetaminophen within 72 hours prior to study entry.

Other protocol-defined inclusion/exclusion criteria may apply