Efficacy of Oral Azacitidine Plus Best Supportive Care as Maintenance Therapy in Subjects With Acute Myeloid Leukemia (AML) in Complete Remission

Key Inclusion Criteria:

1. Male or female participants ≥ 55 years of age

2. Newly diagnosed, histologically confirmed de novo acute myeloid leukemia (AML) orAML secondary to prior myelodysplastic disease or CMML (Chronic myelomonocyticleukemia)

3. First complete remission (CR)/ complete remission with incomplete blood countrecovery (CRi) with induction therapy with intensive chemotherapy with or withoutconsolidation therapy within 4 months (+/- 7 days of achieving CR or CRi)

4. Eastern Cooperative Oncology Group (ECOG) performance status - 0, 1, 2, 3

Key Inclusion Criteria in the Extended Phase of the study:

At the Investigator's discretion and with approval of the sponsor, participants meeting all of the following eligibility criteria are eligible to enter the extension phase:

1. All participants randomized into the oral azacitidine or placebo arm and arecontinuing in either the treatment phase or follow-up phase of the CC-486-AML-001study;

• Participants randomized to oral azacitidine treatment arm and continuing in thetreatment phase demonstrating clinical benefit as assessed by the investigatorare eligible to receive oral azacitidine in the extension phase (EP);

• Participants randomized into placebo arm of the study will not receive oralazacitidine in the EP, but will be followed for survival in the EP;

• Participants currently in the follow-up phase will continue to be followed forsurvival in the EP;

2. Participants who have signed the informed consent for the EP of the study;

3. Participants who do not meet any of the criteria for study discontinuation

Key Exclusion Criteria:

1. AML with inversion (inv)(16), translocation = t(8;21), t(16;16), t(15;17), ort(9;22) or molecular evidence of such translocations

2. Prior bone marrow or stem cell transplantation

3. Have achieved CR/CRi following therapy with hypomethylating agents

4. Diagnosis of malignant disease within the previous 12 months

5. Proven central nervous system (CNS) leukemia