Gene Therapy Keeps ‘Bubble Boy’ Disease At Bay In 8 Children
Researchers say they are achieving success in curing the genetic defect that causes some children to be born without immune defenses, a rare condition made famous in the 1970s by a Texas boy who lived most of his short life in a sterile “bubble.”
Scientists now report that 8 out of 9 young children given gene therapy for a type of severe combined immunodeficiency disease, called SCID-X1, are alive and living amid the everyday microbial threats that would otherwise have killed them. The oldest is just over 3 years old.
"They live pretty normal lives," investigator David Williams tells Shots. “It’s amazing. Without treatment, it’s a pretty uniformly fatal disease.”
Equally important, these children are so far showing no signs of the cancers that developed a decade ago in 5 out of 20 children given an earlier version of the same gene therapy. Those treatment-related cancers temporarily brought such gene therapy experiments to a screeching halt.
The latest gene therapy experiment used a “self-inactivating” virus to deliver the corrective gene into the children’s blood stem cells. This new viral vector apparently doesn’t flip switches that give rise to leukemia, as the old vector did.
"We’re not saying these children are completely free from any risk," says Williams, who was to report on the trial Saturday morning at the American Society of Hematology meeting in New Orleans. "But we’re quite happy with the results we have so far and feel confident that the vector is safer in every way we can look."
Williams works with the Cancer and Blood Disorders Center at Boston Children’s Hospital and Dana-Farber Cancer Institute. He says one of the nine children died of an overwhelming infection that he had “before the gene-corrected cells could fully engraft and fight off the infection.”
One other child didn’t get as much benefit from the gene therapy as hoped. He’s going to get another dose of the gene-corrected stem cells.
Photograph: David Vetter was born with SCID and spent his life in a bubble that protected him from germs. He died at age 12 in 1984. Here his father and Dr. Mary Ann South of David’s medical team were attending to the yellow hoses that provided his protective suit with filtered air. (Wikimedia. org)