This is a clinical trial for men and women with relapsed or refractory acute myeloid leukemia, acute lymphoid leukemia, chronic myeloid leukemia or myelodysplastic syndrome.

The purpose of this study is to determine how the experimental agent CPX-351 works in reducing the growth of leukemia cells prior to a double umbilical cord blood transplant.

CPX-351 is a formulation of a fixed combination of the antitumor drugs Cytarabine and Daunorubicin, contained in a fat droplet (liposome). It is possible that fixing the combination in a fat droplet is superior to administering Cytarabine and Daunorubicin individually in the treatment of acute leukemia. It is hoped that by providing CPX-351 prior to transplant, a reduction in leukemia cells will occur and will improve the chance for a successful engraftment of healthy stem cells from two umbilical cords.

Historically, umbilical stem cell transplant has not been as effective for people with resistant leukemia. Adding CPX-351 prior to transplant may have a beneficial effect on the outcome of a double umbilical cord transplant.