The study will be open for enrollment until the planned number of approximately 500 Philadelphia Chromosome Positive (Ph+) patients have been randomized (approximately 250 Ph+ patients in each treatment arm; a total of approximately 530 Ph+ and Ph- patients). All patients will be treated and/or followed for approximately 5 years (240 weeks) after randomization until the study has closed. Patients who discontinue study therapy early due to disease progression or intolerance to study medication will continue to be followed yearly for survival for up to approximately 5 years (240 weeks) after randomization.