CPX-351 in Treating Patients With Relapsed or Refractory High Risk Myelodysplastic Syndrome or Chronic Myelomonocytic Leukemia

This study is testing a drug called CPX-351 — a special formulation that packages two chemotherapy drugs together — in patients with high-risk myelodysplastic syndrome (MDS) or chronic myelomonocytic leukemia (CMML) that has not responded to or relapsed after standard treatment. **You may be eligible if...** - You have been diagnosed with MDS or CMML by standard World Health Organization criteria - Your disease did not respond to at least 4 cycles of standard treatment (azacitidine, decitabine, or related drugs) or has relapsed after initial improvement - Your disease is classified as intermediate-2 or high risk with more than 5% abnormal cells (blasts) in the bone marrow - You are either ineligible for or have chosen not to pursue a stem cell transplant **You may NOT be eligible if...** - You have a condition preventing safe administration of chemotherapy - You have certain active infections or significant organ dysfunction - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.