International gene therapy trial for 'bubble boy' disease shows promising early results

Eight of nine children treated doing well, according to data presented at 55th American Society of Hematology Annual Meeting and Exposition

Researchers reported promising outcomes data for the first group of boys with X-linked severe combined immunodeficiency syndrome (SCID-X1), a fatal genetic immunodeficiency also known as "bubble boy" disease, who were treated as part of an international clinical study of a new form of gene therapy. The mechanism used to deliver the gene therapy is designed to prevent the serious complication of leukemia that arose a decade ago in a similar trial in Europe, when one-quarter of boys treated developed the blood cancer.

Eight of the nine boys registered to date in the new trial are alive and well, with functioning immune systems and free of infections associated with SCID-X1, between nine and 36 months following treatment, according to Sung-Yun Pai, MD, a pediatric hematologist-oncologist from Dana-Farber/Boston Children's Cancer and Blood Disorders Center. She presented the study's findings at the 55th annual meeting of the American Society of Hematology in New Orleans on behalf of the Transatlantic Gene Therapy Consortium (TAGTC). The investigators continue to monitor the children for signs of treatment-associated leukemia, which developed three to five years post-treatment in the prior trial. They point to surrogate biological markers that give them hope the viral vector used to deliver the new treatment is safe.