A Study of the Drug IMGN632 in Children With Leukemia That Has Come Back After Treatment or is Difficult to Treat

This phase I/II trial finds the highest safe dose of IMGN632 that can be given with other chemotherapy without causing severe side effects, studies what kind of side effects IMGN632 may cause, and determines whether IMGN632 is a beneficial treatment for leukemia in children that has come back after treatment or is difficult to treat. IMGN632 is a monoclonal antibody linked to a chemotherapy drug. IMGN632 is a form of targeted therapy because it attaches to specific molecules (receptors) on the surface of cancer cells, known as CD123 receptors, and delivers the chemotherapy drug to kill them. Giving IMGN632 with other chemotherapy may cause the leukemia to stop growing or to shrink for a period of time.