HLA-Mismatched Peripheral Blood Mobilized Hematopoietic Precursor Cell Transplantation for Hematological Malignancies

Overview

Many patients with hematological malignancies potentially curable by bone marrow transplantation are not considered for transplantation because an HLA identical family or unrelated donor is unavailable. For these patients the only curative option is a transplant from a partially matched family donor. Such transplants are feasible but are less successful than matched sibling donor transplants. The main problems with mismatched transplants are graft rejection, graft-vs-host disease, and regimen-related mortality. This restricts the use of mismatched transplants to patients less than 45 years at high risk of dying from the hematological malignancy. This protocol evaluates a new preparative regimen designed to ensure stem cell engraftment by increased immunosuppression, followed by a G-CSF mobilized T cell depleted, stem cell rich, peripheral blood progenitor cell (PBPC) transplant from a mismatched related donor in patients with high risk hematological malignancies. This phase I study evaluates engraftment and GVHD following T cell depleted, HLA-mismatched PBPC transplants. Stopping rules will be used to make modifications to the protocol in the event of graft failure. The end points of the study are graft take, acute and chronic GVHD, leukemic relapse, transplant-related mortality, death and leukemia-free survival. Patients will be followed up for 5 years. It is planned to treat up to 35 patients aged between 10 and 45 years.

Many patients with hematological malignancies potentially curable by bone marrow transplantation are not considered for transplantation because an HLA identical family or unrelated donor is unavailable. For these patients the only curative option is a transplant from a partially matched family donor. Such transplants are feasible but are less successful than matched sibling donor transplants. The main problems with mismatched transplants are graft rejection, graft-vs-host disease, and regimen-related mortality. This restricts the use of mismatched transplants to patients less than 45 years at high risk of dying from the hematological malignancy. This protocol evaluates a new preparative regimen designed to ensure stem cell engraftment by increased immunosuppression, followed by a G-CSF mobilized T cell depleted, stem cell rich, peripheral blood progenitor cell (PBPC) transplant from a mismatched related donor in patients with high risk hematological malignancies. This phase I study evaluates engraftment and GVHD following T cell depleted, HLA-mismatched PBPC transplants. Stopping rules will be used to make modifications to the protocol in the event of graft failure. The end points of the study are graft take, acute and chronic GVHD, leukemic relapse, transplant-related mortality, death and leukemia-free survival. Patients will be followed up for 5 years. It is planned to treat up to 35 patients aged between 10 and 45 years.