Ten young children born without functioning immune systems and lacking the ability to fight infections are on track for healthier lives thanks to a new gene therapy treatment pioneered at UC San Francisco, reports a Dec. 22 study in the New England Journal of Medicine.
The children have Artemis-SCID, a very rare genetic disorder that is typically treated with a bone marrow transplant from a healthy donor, ideally a matched brother or sister. The new gene therapy allows researchers to treat newly diagnosed babies with their own cells — adding a healthy copy of the Artemis gene to the baby’s harvested marrow stem cells, then infusing the corrected stem cells back into their bodies — in hopes of avoiding many of the short- and long-term complications of the standard treatment, including death.
The children in the trial — all under the age of 5 — are living at home with their families, attending daycare and preschool, playing outside, and living normal lives, said Mort Cowan, MD, UCSF pediatrics professor and the trial’s lead investigator.
“Already, the course of their illness is so much better than with the typical treatment,” said Cowan, who has treated more than 30 children with Artemis-SCID using standard bone marrow transplants. “I’ve never seen results like this in any of the other kids. It’s amazing.”
Gene correction has been used before in patients with other genetic forms of SCID, but its use in Artemis-SCID is significant because these patients usually respond more poorly to standard bone marrow transplants. Complications can include rejecting the marrow graft, graft-vs.-host disease — in which the donor T cells attack the recipient’s tissues — chronic infections leading to organ damage, stunted growth, and premature death.
Signs of Stronger Immunity
The first outcome of the Phase I/II trial involved the safe transfusion of gene-corrected cells that would differentiate into white blood cells by 42 days after infusion. Researchers theorized patients would need less chemotherapy to prepare their marrow for transfusion when their own cells were being used; thus only 25% of a full dose of busulfan was administered. The second outcome was T-cell reconstitution at 12 months, a measurement of the strength of the immune system.
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