Clinical Trial: Lentiviral Gene Therapy for Adenosine Deaminase (ADA) Deficiency

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Interventional




Official Title: Phase I/II, Non-controlled, Open-label, Non-randomised, Single-centre Trial to Assess the Safety and Efficacy of EF1αS-ADA Lentiviral Vector Mediated Gene Modification of Autologous CD34+ Cells F

Brief Summary:

Adenosine Deaminase (ADA) is an enzyme, needed by body to develop lymphocytes of the immune system. Children who are born in mutations with mutations in ADA gene have severe combined immunodeficiency (SCID). Children with ADA-deficient SCID generally die in the first year of life from severe infections because they do not have immune system that can fight against infections. ADA deficient individuals can be cured by bone marrow transplant, but the best results are obtained when there is fully matched family donor is available. In the absence of a matched related donor, transplants from unrelated or mismatched donors have a much worse outcome. There is a form of enzyme therapy (PEG-ADA) for ADA-deficient SCID, in which children receive injections of purified ADA enzyme 1-2 times each week. These injections can allow the immune system to recover to a level that protects children from infections.

However, these injections have to be given weekly and are very expensive (£ 125,000 - 200,000 annually) and the recovery of the immune system is not sustained over time.

Gene therapy for ADA-deficient SCID could be performed by introducing a normal copy of the human ADA gene into the blood forming stem cells of the patient's bone marrow by using a new type of gene delivery system (in this trial called a lentiviral vector). The gene corrected cells are then transplanted back into the patient after small dose of chemotherapy. These gene corrected stem cells can survive into the body and make lymphocytes. In this trial, we will determine whether gene therapy for ADA-deficient SCID using lentiviral vector is safe, feasible and effective