In this study, people will take a medicine called R289 by mouth once or twice a day. The study has two parts: one part is to find the best dose, and the other part is to test two different doses.
You may take the medicine at home or at the clinic. You will visit the clinic regularly for tests like blood work, physical check-ups, and heart exams. Some visits may take up to 8 hours.
You can stay in the study as long as the medicine is helping and the side effects are not too strong.

Lower-risk myelodysplastic syndromes (LR-MOS).

People in this study must:

• Be 18 years old or older.
• Have a blood problem called lower-risk myelodysplastic syndromes (LR-MDS).
• Have tried other treatments that did not work or the disease came back.
• May need regular red blood cell transfusions to feel better.
• Cannot be pregnant or breastfeeding.

This study is testing a new medicine called R289 to see if it can help people with a blood problem called lower-risk myelodysplastic syndromes (LR-MDS). Doctors want to learn how safe the medicine is and how well it works. They also want to find the best dose and see if it can help people need fewer blood transfusions.