Conditions: Immunologic Deficiency Syndromes
Keywords: SCID gene therapy Adenosine deaminase retroviral vector
Allocation: NA | Intervention model: SINGLE_GROUP
Enrollment: 12
Healthy volunteers: no

Brief summary:
This is a phase I/II protocol to evaluate the safety and efficacy of ADA gene transfer into hematopoietic stem/progenitor cells for the treatment of adenosine deaminase (ADA)-deficiency. This condition is an autosomal recessive form of Severe Combined Immunodeficiency (SCID) characterized by impaired immune responses, recurrent infections, failure to thrive and systemic toxicity due to accumulation of purine metabolites. Transplants from an human leukocyte-antigen (HLA)-identical sibling donor is the treatment of choice, but available for a minority of patients. The use of alternative bone marrow donors or enzyme replacement therapy is associated with important drawbacks. The drug product studied in this protocol consists of autologous cluster of differentiation (CD)34+ hematopoietic stem/progenitor cells engineered ex vivo with a retroviral vector encoding the therapeutic gene ADA. The engineered CD34+ cells are infused following a nonmyeloablative conditioning with busulfan to make space in the bone marrow. The study objectives are: a) to evaluate the safety and the clinical efficacy of gene therapy, in the absence of enzyme replacement therapy; b) to evaluate the biological activity (engraftment, ADA expression) of ADA transduced CD34+ cells and their hematopoietic progeny. c) to evaluate the immunological reconstitution and purine metabolism after gene therapy.

Detailed description:
The safety of the study will be evaluated by description of all adverse events and adverse drug reactions.

The study is aimed at reaching the minimum sample size of ten patients.

Arms:
arm 1: Infusion of autologous CD34+ cells transduced with retroviral vector encoding ADA after non-myeloablative conditioning with busulfan

Interventions: intervention 1: Gene Therapy intervention 2: Busulfan
Intervention descriptions: intervention 1: Infusion of autologous CD34+ cells transduced with retroviral vector encoding ADA after non-myeloablative conditioning with busulfan intervention 2: Busulfan is used for non-myeloablative conditioning

Protocol document: