Donor Enhancement With Plerixafor Post Myeloablative Allogeneic Transplant

This phase I/II clinical trial will test the safety and the efficacy of post transplant administration of plerixafor in enhancing hematological recovery in humans. Patients who are appropriate candidates for myeloablative allogeneic stem cell transplantation from an HLA-matched sibling, matched unrelated donor or umbilical cord blood are eligible for enrollment. The investigators plan to enroll a total of 50 patients for this study (30 patients with HLA-matched sibling or matched unrelated donor transplant, and 20 patients with umbilical cord blood transplant). During phase I study, a small number of patients (3-6 patients from each group) will be enrolled to determine the safety of post transplant administration of plerixafor. Patients will receive plerixafor given at 240 µg/kg subcutaneously every other day beginning at day +2 after transplant until day +21 or engraftment. Limiting toxicities are defined as primary or secondary graft failure, plerixafor-related severe premature ventricular arrhythmia or death. If safety criteria are met from the investigators phase I study, the investigators will proceed with phase II study to determine the efficacy of post transplant administration of plerixafor in enhancing haematological recovery. The experimental aspect of this study is the use of plerixafor and all other aspects of care will be in line with the standard of care. Both Phase I and Phase II patients will be combined for efficacy analysis, and data collected from this study will be compared with the investigators historical control. The results from this study will set the stage and provide the justification for a larger phase 3 trial.