Selective Depletion of Alloreacting T Cells Using a Photodepletion Technique to Prevent GVHD After HLA-Matched Peripheral Blood Stem Cell Transplantation for Subjects With Hematologic Malignancies

Peripheral blood stem cell transplant research carried out by the NHLBI BMT Unit focus on approaches in transplant techniques designed to decrease graft versus host disease (GVHD), increase the graft-versus-leukemia (GVL) effect, and/or reduce the risk for post-transplant graft rejection or disease relapse.

Ex vivo selective depletion of alloreacting T cells, hereafter referred as selective depletion (SD), represents a translational strategy aiming to reduce severe GVHD whilst preserving GVL. We found that selectively depleted transplants are safe to administer and associated with less severe acute GVHD. This protocol is designed to evaluate the safety and efficacy of photodepletion (PD) as an improved selective depletion procedure in the HLA-matched peripheral blood stem cell transplant setting and to determine whether post-transplant immunosuppression with cyclosporine is necessary to prevent severe GVHD after a photodepleted transplant.

The protocol will accrue subjects ages 18-75 who are diagnosed with a hematological malignancy where allogeneic stem cell transplantation from an HLA-matched sibling would be normally indicated. Diagnostic categories will include acute and chronic leukemias, myelodysplastic syndromes, B-cell lymphomas, multiple myeloma, and myeloproliferative syndromes.

Participants have a central intravenous (IV) line placed into a large vein. The tube is used for giving the donated stem cells and antibiotics and other medicines, for transfusions of red blood cells and platelets, and for collecting blood samples. Treatment starts with a conditioning regimen of chemotherapy (fludarabine and cyclophosphamide) and total body irradiation to suppress immunity and prevent rejection of the donated stem cells. The day after chemotherapy ends, the stem cells are given through the central line. This is followed by transfusion of the donor's immune cells, which have been treated to remove cells that could cause severe GVHD. Also to minimize the risk of GVHD, patients are given cyclosporine. Not all participants receive the same amount of this drug; in order to determine how much immunosuppression is needed to protect against severe GVHD, the length of treatment with cyclosporine varies among patients, depending on when they entered the study and how well preceding patients did.

The average hospital stay for stem cell transplantation is 3 to 4 weeks. Patients return for frequent follow-up visits for the first 2 to 4 months after transplantation. The patient's referring physician is asked to send results of any laboratory testing to the NIH researchers at least every 3 months for the first 3 years and annually thereafter. Patient follow-up visits are scheduled at NIH at 1, 2, and 3 years after transplantation. After 3 years, participants are offered the opportunity to enroll in NHLBI's long-term evaluation and follow-up care protocol.