This clinical trial is for men and women who have myeloid disease, a disease caused by blood cells that are not working properly.
   
The purpose of this study is to test the safety and effectiveness of an experimental study drug called DFV890 in patients diagnosed with a myeloid disease. DFV890 is considered “experimental” because it has not been approved by the United States Food and Drug Administration (FDA) for the treatment of myeloid diseases. By doing this study, we hope to find the appropriate dose regimen of DFV890 that can be given safely to people with myeloid disease.
   
DFV890 is a medicine that acts against certain cells in the immune system. These immune cells are produced at high levels in patients with myeloid disease. Scientific data shows that uncontrolled inflammation that begins in the bone marrow can lead to blood cell damage and abnormalities. DFV890 can reduce inflammation and may provide an improvement in the signs and symptoms of participants’ medical condition.

Participants in the first part of the study will be randomly assigned (assigned by chance or by a flip of a coin) to receive either 25 mg DFV890 or 50 mg DFV890 twice daily as tablets until a recommended dose is determined. Once a recommended dose is determined, in the second part of the study, all study participants will receive the recommended dose. The study doctor will inform participants of the dose of study drug that they will receive and which part of the study they are in before starting the drug.

Participants will need to come to the study site for all visits associated with each cycle. A cycle consists of 28 days. Participants will receive DFV890 for as long as they are able to tolerate the study drug based on the study doctor’s assessment. Therefore, it is not possible to predict exactly how long study participation will last.