Acute Lymphoblastic Leukemias clinical trials

Stem Cell Transplantation for Patients With Hematologic Malignancies

Childhood leukemias which cannot be cured by chemotherapy alone may be effectively treated by allogeneic bone marrow transplantation. Moreover, for patients with chronic myelogenous leukemia (CML), allogeneic hematopoietic stem cell transplantation (HSCT) is the only proven curative modality of treatment. Patients who have received hematopoietic stem cells from an HLA matched sibling donor have proven to be less at risk for disease relapse and regimen related toxicity. However, about 70% of patients in need of HSCT do not have an HLA matched sibling donor. This necessitates the search for alternative donors, which may increase the risk of a poor outcome. The nature of the hematopoietic stem cell graft has been implicated as a primary factor determining these outcomes. The standard stem cell graft has been unmanipulated bone marrow, but recently several advantages of T-lymphocyte depleted bone marrow and mobilized peripheral blood progenitor cells (PBPC) have been demonstrated. However, T-cell depletion may increase the risk of infectious complications and leukemic recurrence while an unmanipulated stem cell graft may increase the risk of graft vs. host disease (GVHD). A key element in long range strategies in improving outcomes for patients undergoing matched unrelated donor (MUD) HSCT is to provide the optimal graft. The primary objective of this clinical trial is to estimate the incidence of acute GVHD in pediatric patients with hematologic malignancies who receive HSCT with an unmanipulated marrow graft. The results of this study can be used as the foundation for future trials related to engineering unrelated donor graft.