Related Hematopoietic Stem Cell Transplantation (HSCT) for Genetic Diseases of Blood Cells

Thalassemia Clinical Trial

Official title: Protocol for Related Donor Hematopoietic Stem Cell Transplantation (HSCT) for Treatment of Symptomatic Genetic Lymphohematological Diseases

Status Completed

Clinical Trial Summary

Many genetic diseases of lymphohematopoietic cells (such as sickle cell anemia, thalassemia, Diamond-Blackfan anemia, Combined Immune Deficiency (CID), Wiskott-Aldrich syndrome, chronic granulomatous disease, X-linked lymphoproliferative disease, and metabolic diseases affecting hematopoiesis) are sublethal diseases caused by mutations that adversely affect the development or function of different types of blood cells. Although pathophysiologically diverse, these genetic diseases share a similar clinical course of significant progressive morbidity, overall poor quality of life, and ultimate death from complications of the disease or its palliative treatment. Supportive care for these diseases includes chronic transfusion, iron chelation, and surgery (splenectomy or cholecystectomy) for the hemoglobinopathies; prophylactic antibiotics, intravenous immunoglobulin, and immunomodulator therapies for the immune deficiencies; and enzyme replacement injections and dietary restriction for some of the metabolic diseases. The suboptimal results of such supportive care measures have led to efforts to implement more aggressive therapeutic interventions to cure these lymphohematopoietic diseases. The most logical strategies for cure of these diseases have been either replacement of the patient's own hematopoietic stem cells (HSC) with those derived from a normal donor allogeneic bone marrow transplant (BMT) or hematopoietic stem cell transplant (HSCT), or to genetically modify the patient's own stem cells to replace the defective gene (gene therapy).

Clinical Trial Description

The present study is to evaluate de-escalation of the cyclophosphamide (CY) dose in an innovative conditioning regimen with fludarabine and alemtuzumab as additional agents to achieve immunoablation, in combination with Busulfan (BU) to achieve myeloablation. Replacement of at least part of the cyclophosphamide dose by fludarabine in the conditioning regimen would be expected to maintain immunosuppression (and, therefore, engraftment) while reducing transplant-related complications (mucositis, hepatotoxicity, cardiotoxicity, pulmonary toxicity, hemorrhagic cystitis, mucositis, and possibly GVHD), thereby improving disease-free survival rates. Similarly, the potential benefits of alemtuzumab in the proposed conditioning regimen are increased rates of hematopoietic engraftment with less toxicity than that observed with cyclophosphamide, ultimately resulting in improved immune function and enhanced quality of life (12,13). A fludarabine/alemtuzumab-based, less intensive conditioning regimen with adequate immunosuppressive activity could conceivably allow more successful engraftment of stem cells from related donors in patients with genetic lymphohematological diseases, as well as lower rates of transplant-related mortality.

Regimen-related toxicity is also believed to be a major contributing factor to GVHD (14). Therefore, conditioning regimens that cause less tissue injury may also lead to reduced GVHD. In the present study, the use of alemtuzumab in the conditioning regimen may be an added benefit, as this antibody causes T-cell depletion, thus, the risk of GVHD may also be reduced (15). The overall goal of the study is to improve the therapeutic index of HSCT by decreasing and, if possible, eliminating cyclophosphamide as a component of the pre-transplant conditioning for patients with genetic diseases of lymphohematopoiesis. The investigation will explore the risks and benefits of the proposed novel-conditioning regimen using a decreased dose of cyclophosphamide and additional immunosuppression with fludarabine and alemtuzumab to prevent graft rejection and recurrence of disease. The investigators will evaluate this regimen's impact on conditioning-related morbidity and mortality, and measure the success of the transplant procedure by engraftment and disease-free survival. If this regimen is able to successfully permit engraftment and reduce regimen-related toxicity, the next phase of treatment will test a further dose de-escalation for cyclophosphamide. It is anticipated that there will be four dose levels of cyclophosphamide in the overall study: 1) 105 mg/kg; 2) 70 mg/kg; 3) 35 mg/kg; and then finally, 4) 0 mg/kg. This study design was chosen to minimize study risks possibly associated with substitution of fludarabine and alemtuzumab for CY as immunoablation. The present protocol represents Level 1 in the study design; an amended protocol will be prepared prior to further de-escalation of the cyclophosphamide dose. ;

Study Design

Allocation: Non-Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Allogeneic Transplantation,
• Anemia, Diamond-Blackfan
• Bone Marrow Transplantation
• Chronic Granulomatous Disease
• Combined Immune Deficiency
• Diamond-Blackfan Anemia
• Genetic Diseases
• Genetic Diseases, Inborn
• Granuloma
• Granulomatous Disease, Chronic
• Immunologic Deficiency Syndromes
• Lymphoproliferative Disorders
• Metabolic Diseases
• Pediatrics
• Peripheral Blood Stem Cell Transplantation
• Stem Cell Transplantation
• Thalassemia
• Wiskott-Aldrich Syndrome
• X-linked Lymphoproliferative Disease

• NCT number: NCT02512679
• Study type: Interventional
• Source: Children's Hospital Los Angeles
• Status: Completed
• Phase: Phase 2
• Start date: February 2007
• Completion date: February 2014