Gene Therapy Restores Immune Function in 95% of Children with ADA-SCID

Researchers from UCLA, University College London, and Great Ormond Street Hospital have reported significant success in using gene therapy to restore immune function in children diagnosed with ADA-SCID, a rare genetic disorder that severely impairs the immune system. Among the 62 children treated between 2012 and 2019, 59 have shown restored and maintained immune function. This breakthrough offers new hope for children affected by this life-threatening condition, which, if left untreated, can lead to fatal infections within the first two years of life. ADA-SCID is caused by mutations in the ADA gene, which is crucial for producing an enzyme necessary for immune function. Traditional treatment options, such as bone marrow transplants or enzyme replacement therapy, come with limitations and potential risks.

The gene therapy approach involves collecting a child's blood stem cells and using a modified lentivirus to deliver a healthy copy of the ADA gene. Once infused back into the patient, these corrected stem cells begin to produce healthy immune cells, reconstituting the immune system over six to twelve months. The findings were published in the New England Journal of Medicine, detailing the long-term outcomes of the gene therapy. Dr. Donald Kohn, a senior author of the study, noted the durability and stability of immune function in the treated patients, which has remained consistent beyond the initial recovery period. Most adverse events reported were mild and related to preparatory procedures rather than the gene therapy itself.

Notably, the therapy was successful in nearly all cases, with only three patients not achieving the desired outcome; however, they were able to revert to standard care options. More than half of the children treated received a frozen preparation of corrected stem cells, which yielded similar success rates as those who received fresh cells. This method of cryopreservation enhances accessibility, allowing stem cells to be collected locally, processed, and shipped back to hospitals. This reduces the need for families to travel long distances for treatment and allows for better testing and quality control before the therapy is administered.

Looking forward, the research team is now focused on obtaining FDA approval for the gene therapy. With support from the California Institute for Regenerative Medicine, they aim to complete the necessary steps for approval within the next two to three years. The potential for this therapy to become widely available could revolutionize the treatment landscape for ADA-SCID and similar genetic disorders, offering a safe and effective solution for affected children worldwide.