We are doing this study to find the most effective, safe dose of an experimental drug called CLN-049 (the study drug) for people with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS).

Relapsed/Refractory Acute Myeloid Leukemia (AML) or Myelodysplastic Syndrome (MDS)

Adults ages 18+ who:

• Are diagnosed with AML or MDS
• Did not respond to standard therapies or had their disease come back after treatment
• Have not received any radiation therapy within 28 days of starting the study drug
• Have not been treated with immunotherapy with checkpoint inhibitors within 6 weeks of starting the study drug
• Have never been treated with chimeric antigen receptor (CAR-T) cell therapy or other types of modified T cell therapy

For more information about who can join this study, please contact the study team at terri.lucas@duke.edu or 919-681-6580.

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 an ECG
• Have blood and urine samples
• Have a bone marrow biopsy

If you are eligible to join, you will proceed to the study drug portion of the study. Depending on when you join the study, you will be assigned to Part A, Part B, or Part C.

If you join the study and participate in Part A or Part B, you will get a dose of the study drug through an intravenous (IV) infusion that takes about 1 hour. Participants in Part A will get only 1 dose of the study drug. Participants in Part B will get a dose of the study drug every 7 days.

If you join the study and participate in Part C, you will get a dose of the study drug as a subcutaneous injection (shot under the skin) that takes about 1 minute. Participants in Part C will get a dose of the study drug every 7 days.

If you are in Part B or Part C of the study, you will take the study drug for up to 2 years, unless you or the study doctor decide that you are not getting a benefit and should stop.