Administration of Donor T Cells With the Caspase-9 Suicide Gene

If the patient is doing well after the stem cell transplant, and does not have severe GvHD, s/he will be eligible to receive the special "iCasp9" T cells from Day 30 to 90 after transplant. The specially selected and treated T cells will be given by vein (IV) once. This is a dose escalation study. This means that at the beginning, patients will be started on the lowest dose (1 of 5 different levels) of T cells. Once that dose schedule proves safe, the next group of patients will be started at a higher dose. This process will continue until all 5 dose levels are studied. If the side-effects are too severe, the dose will be lowered or the T cell injections will be stopped. If the patient develops GvHD after being given the specially treated T cells, we will prescribe AP1903, which has been shown to kill cells carrying the iCasp9 gene. This drug will be given as a 2-hour IV infusion. We will continue to follow the patient weekly in the bone marrow transplant clinic for the first month after the infusion, to check for side-effects of the treatment and for GvHD. The patient will have the standard tests performed that all patients have after transplant, even when not receiving special T cells.