This study is separated into three periods: Screening and Registration, Treatment and Follow-up periods. Before the patient can receive the study drug the doctor will perform tests to find out whether he/she can participate in the study. This is done during the Screening Period. If the patient and the treating physician determine that the patient is eligible to participate in the study, the patient will be registered in the study and assigned to receive one of the investigational dose levels of oral azacitidine.