In ADA-SCID, allogeneic hematopoietic (blood) stem cell transplants from non-matched sibling donors are a high risk procedure. Additionally, the efficacy of chronic enzyme replacement therapy is uncertain in the long-term. A team at UCLA is using a patient’s own blood stem cells to try and rebuild the damaged immune systems of patients with ADA-SCID. They will use what’s called a lentiviral vector to deliver genetic material into the blood stem cells, correcting the genetic flaw that causes SCID. It’s hoped this will create a new blood system and a healthy immune system. Preliminary data indicates that OTL-101 – a stem cell gene therapy developed by UCLA and Orchard Therapeutics Limited – may significantly improve outcomes compared to available therapies.