Sickle Cell Disease and Thalassemia Clinical Trial
Official title:
Nonmyeloablative Allogeneic Peripheral Blood Mobilized Hematopoietic Precursor Cell Transplantation for Severe Congenital Anemias Including Sickle Cell Disease and Thalassemia
The design of the study incorporates the following features: 1. This is a phase II study to determine the safety and therapeutic potential of a new transplant approach (disease-free survival, graft versus myeloma effect) and to evaluate its toxicity profile (immediate toxicity, graft-versus-host disease, graft rejection, mortality) in a patient population with severe congenital anemias. 2. The patient cohort to be studied: Those patients with severe sickle cell disease and thalassemia who have risk factors for high mortality and morbidity related to their disease 3. Transplant Conditioning Regimen - Immunosuppression without myeloablation: Patients will receive conditioning sufficient to allow donor lympho-hematopoietic engraftment without complete marrow ablation. If the graft is rejected, the patient will reconstitute autologous marrow function. We will use a combination of low dose irradiation, Alemtuzumab (Campath®), and sirolimus. 4. Peripheral blood hematopoietic progenitor cell (PBPC) transplant: An unmanipulated peripheral blood stem cell collection from a filgrastim (G-CSF) stimulated HLA-matched donor should improve the chance of engraftment because of the high stem cell dose (5 x 106/kg CD34+ cells) and the presence of donor lymphocytes. To reduce the risk of GVHD, patients will receive sirolimus before and after the transplant. The sirolimus will be tapered as necessary to minimize any graft versus host disease while still maintaining adequate chimerism.
A human lymphocyte antigen (HLA)-matched sibling donor will receive filgrastim (G-CSF) 10 to16 µg/kg/d subcutaneously or intravenously for up to 6 days with apheresis collections of PBPC on day 5 (and day 6 if required). The product will be collected by leukophoresis with a goal of ≥ 10 x 106 CD34+ cells/kg, with a minimum of 5 x 106 CD34+ cells/kg. The patient will receive a preparative regimen of Alemtuzumab to be infused on days -7 to -3, followed by 300 cGy TBI given as a single dose on day -2. Sirolimus at a dose of 5mg/day to maintain trough levels between 10-15ng/ml will be started on day -1. The PBPC graft targeted to deliver 10 x 106 CD34+ cells/kg (at minimum, 5 x 106 CD34+ cells/kg) will be infused on day 0 On days +14, +30, +60 and +100 the chimeric status of patients will be assessed by microsatellite analysis of the peripheral blood. More frequent monitoring may be required. Sickle cell patients with pulmonary hypertension will meet with a Pulmonary Medicine Consult to determine appropriate management prior to SCT. Patients with fever or suspected minor infection should await resolution of symptoms before starting the conditioning regimen. Iron chelation must be discontinued > 48 hours before initiating the conditioning regimen. Hydroxyurea must be discontinued one day prior to initiating the conditioning regimen. ;