A Multicenter Phase 3, Open-Label Study of Bosutinib Versus Imatinib in Adult Patients With Newly Diagnosed Chronic Phase Chronic Myelogenous Leukemia

1. Molecular diagnosis of CP CML of ≤ 6 months (from initial diagnosis). 2. Adequate hepatic, renal and pancreatic function. 3. Age ≥ 18 years.

1. Any prior medical treatment for CML, including tyrosine kinase inhibitors (TKIs), with the exception of hydroxyurea and/or anagrelide treatment, which are permitted for up to 6 months prior to study entry (signature of ICF) if suitably approved for use in the subject's region. 2. Any past or current Central Nervous System (CNS) involvement, including leptomeningeal leukemia. 3. Extramedullary disease only. 4. Major surgery or radiotherapy within 14 days of randomization. 5. History of clinically significant or uncontrolled cardiac disease. 6. Known seropositivity to human immunodeficiency virus (HIV), current acute or chronic hepatitis B (hepatitis B surface-antigen positive), hepatitis C, cirrhosis or evidence of decompensated liver disease. Patients with resolved Hepatitis B can be included. 7. Recent or ongoing clinically significant GI disorder, e.g. Crohn's Disease, Ulcerative Colitis, or prior total or partial gastrectomy. 8. History of another malignancy within 5 years with the exception of basal cell carcinoma or cervical carcinoma in situ or stage 1 or 2 cancer that is considered adequately treated and currently in complete remission for at least l2 months. 9. Current, or recent (within 30 days, or 5 half-lives of investigational product) participation in other clinical trials of investigational agents and/or containing interventional procedures deemed contrary to the objectives and conduct of this trial.