Effect of Food on Blood Levels of ASTX727

This is a Phase 1b, multicenter, open-label, randomized, two-sequence, crossover study of ASTX727 in participants with MDS, including refractory anemia with excess blasts in transformation or CMML, and AML. Participants will continue to be enrolled until evaluable data is collected from 12 participants. It is expected that approximately 18 participants will be enrolled in total. This study will be conducted in 28-day cycles. All participants will take part in Cycle 1 and may continue into Cycles ≥2 at the investigator's discretion. Participants will receive one tablet of ASTX727 containing 100 mg cedazuridine and 35 mg decitabine once daily for 5 days in 28-day cycles starting from Cycle 1 Day 1. Participants will be randomized in a 1:1 ratio to receive high-calorie, high-fat breakfast meal pre-dose on either Day 2 or Day 4 of Cycle 1. Blood will be drawn at specified time points in Cycle 1 on Days 2 through 5 to assess the effect of food on the PK of cedazuridine and decitabine. After completion of the first treatment cycle, participants may continue to receive treatment with ASTX727 at the investigator's discretion for subsequent cycles (Days 1 through 5 of 28-day cycles), until disease progression, unacceptable toxicity, investigator decision to discontinue treatment, or the participant decides to discontinue treatment or withdraw from the study. In Cycles ≥2, participants will fast for 2 hours before and 2 hours after taking the ASTX727 tablet on all dosing days.