Full Haplotype-Mismatched Hematopoietic Stem-Cell Transplantation: A Phase II Study in Patients With Acute Leukemia at High Risk of Relapse

Primary engraftment was achieved in 94 of 101 assessable patients. Six of the seven patients who rejected the primary graft, engrafted after a second transplantation. Overall, 100 of 101 patients engrafted. Acute GvHD developed in eight of 100 patients, and chronic GvHD, in five of 70 assessable patients. Thirty-eight patients died of nonleukemic causes. Relapse occurred in nine of 66 patients receiving transplantation in remission and in 17 of 38 receiving transplantation in relapse. Median follow-up of the 40 patients who survived event-free was 22 months (range, 1 to 65 months). Event-free survival (+/- standard deviation) rate was 48% +/- 8% and 46% +/- 10%, respectively, for the 42 AML and 24 ALL patients receiving transplantation in remission.

Our transplantation procedure provides reliable, reproducible CD34+ cell purification, high engraftment rates, and prevention of GvHD. The mismatched-related transplant emerges as a viable, alternative source of stem cells for acute leukemia patients without matched donors and/or those who urgently need transplantation.