A Randomized Open-label Study of 400 mg Versus 800 mg of Imatinib Mesylate in Patients With Newly Diagnosed, Previously Untreated Chronic Myeloid Leukemia in Chronic Phase (CML-CP) Using Molecular Endpoints.

Inclusion Criteria:

- Patients within 6 months of diagnosis (date of initial diagnosis is the date of first
cytogenetic analysis)

- Diagnosis of chronic myelogenous leukemia (CML) in chronic phase with cytogenetic
confirmation of Philadelphia chromosome of (9;22) translocations and presence of
Breakpoint cluster region gene-abelson proto-oncogene (Bcr-Abl)

- Documented chronic phase CML

- Adequate end organ function as defined by:

- total bilirubin < 1.5 x Upper Limit of Normal (ULN)

- Serum glutamic oxaloacetic transaminase (SGOT) and serum glutamate pyruvate
transaminase (SGPT) < 2.5 x ULN

- creatinine < 1.5 x ULN

Exclusion Criteria:

- Patients in late chronic phase, accelerated phase, or blastic phase are excluded

- Patients who have received other investigational agents

- Patients who received Gleevec/Glivec for any duration prior to study entry, with the
exception of those patients successfully completing [CSTI571A2107 (NCT00428909)]
study immediately prior to the participation in this study

- 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: (a) pregnant, (b) breast feeding, (c) of childbearing potential
without a negative pregnancy test prior to baseline and (d) 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 Eastern Cooperative Oncology Group (ECOG) Performance Status Score ≥
3

- Patients with International normalized ratio (INR) or partial thromboplastin time
(PTT) > 1.5 x ULN, with the exception of patients on treatment with oral
anticoagulants

- Patients with known positivity for human immunodeficiency virus (HIV); baseline
testing for HIV is not required

- Patients with identified sibling donors where allogeneic bone marrow transplant is
elected as first line treatment

Other protocol-defined inclusion/exclusion criteria applied.