• Azacitidine PK substudy: This study contains extra testing to measure the amount of azacitidine that is in your blood. On day 1 of cycle 2, we will take blood from a vein. This is a single visit that will involve you being in the clinic for up to 5 hours. During this time 6 blood samples will be taken (total of about 5 teaspoons). If you do not complete these tests on Day 1 of Cycle 2, it may be possible that you can complete the tests on the first day of a later cycle. Once 55 patients complete the azacitidine PK substudy testing, no further patients will be required to complete these tests