We are doing this study to find out how well an experimental drug called DSP-5336 (the study drug) works in people with AML or ALL.

Mixed Lineage Leukemia (MLL) Rearrangement or Nucleophosmin 1 (NPM1) Mutation

Adults ages 18+ who:

• Are diagnosed with Relapsed or Refractory AML or ALL
• Have a confirmed KMT2A (MLL)-fusion or NPM1 mutation
• Have acceptable organ function

For more information about who can join this study, please contact the study team at 919-660-2077.

If you choose to join this study, you will go through a screening period to find out if you are eligible. During this screening period, you will:

• Have a physical exam
• Have a heart scan (ECG)
• Have blood draws

After the screening period, this study is divided into 2 parts. In Part 1, you will be assigned to either:

• Arm A (not taking a type of antifungal treatment); OR
• Arm B (you are taking a type of antifungal treatment)

In Part 2, you will be assigned to either:

• Arm A [R/R AML with Mixed Lineage Leukemia that is rearranged (MLLr AML)]; OR
• Arm B [R/R leukemia that has the Nucleophosmin 1 gene mutated (NPM1)]

The study drug will be taken by mouth twice daily.

Once you stop taking the study drug, you will enter a follow-up period. The study team will call you approximately every 3 months to see how you are feeling during this period.