Conditioning Regimen for Allogeneic Hematopoietic Stem Cell Transplantation of Patients With Hematological Diseases

Overview

Participants in this study have a hematologic malignancy (a disorder in the bone marrow that affects the body's ability to create blood) that might benefit from receiving an allogeneic stem cell transplant (meaning the cells come from a donor) from a family member or nearly identical matched donor. The donor may either be a matched sibling, a mismatched family member, or an unrelated person. Usually these patients are given high doses of chemotherapy before receiving a stem cell transplant to keep their immune system from rejecting the donor stem cells and to kill any diseased cells that remain in the body. However, this group of patients have a high risk of developing possibly life-threatening treatment-related side effects such as infections, damage to vital organs such as lungs, liver, kidney and heart, as well as graft versus host disease (GVHD). Instead of the high dose chemotherapy and radiotherapy usually given before a transplant, this research study uses a new pre-transplant combination of three drugs, Fludarabine, Anti-CD45 and CAMPATH-1H with low dose radiotherapy. Fludarabine is a chemotherapy drug while Anti-CD45 and CAMPATH-1H are antibodies against certain types of blood cells, including those which are causing this disease. CAMPATH-1H is particularly important because it stays active in the body for a long time after it is given, which means it may work longer to prevent GVHD symptoms. Anti-CD45 may help in eradicating residual malignant cells. All these agents also help in preventing rejection of donor stem cells. This study is designed to give a less intense chemotherapy and radiotherapy, so that the life-threatening toxicities of conventional high dose chemotherapy and radiotherapy regimen can be reduced, while maintaining the ability to cure cancer.

CAMPATH-1H will be given as a daily IV infusion for three days. Fludarabine will be given as a daily IV infusion for four days. Anti-CD45 will be given as a daily IV infusion for 4 days. Patients will then receive radiotherapy (also known as Total Body Irradiation or TBI) for one day. A summary of the treatment follows: * Day - 8: CAMPATH-1H and Fludarabine * Day - 7: CAMPATH-1H and Fludarabine * Day - 6: CAMPATH-1H and Fludarabine * Day - 5: Anti-CD45 and Fludarabine * Day - 4: Anti-CD45 * Day - 3: Anti-CD45 * Day - 2: Anti-CD45 * Day - 1: TBI * Day 0: Stem Cell Infusion (transplant) To help prevent the body from developing GVHD, patients will also receive the drug FK506, starting two days before the transplant and continuing for at least one month. Both the CAMPATH-1H and the Anti-CD45 can cause allergic reactions so patients will be given drugs to help prevent those reactions before receiving daily doses. To see how CAMPATH-1H works in patients with hematologic malignancies, some patients will be asked to participate in pharmacokinetic studies. For this, approximately 13 blood samples will be taken from the central line scheduled before each infusion on Day -8 to Day -6, daily thereafter until Day 0, and then approximately once per week on days 7, 14, 21 and 28 post transplant. No more than 5 teaspoonfuls total will be drawn. To see how Anti-CD45 works in patients with hematologic malignancies some patients will be asked to participate in pharmacokinetic studies. Approximately 22 blood samples will be taken from the central line scheduled before, during and after each infusion and after the end of the last infusion of Anti-CD45. No more than 10 teaspoonfuls total will be drawn over the course of the four anti-CD45 infusions.