Research Shows Gene Therapy Restores the Immune Systems of Infants and Children with Rare Immunodeficiency

The National Institutes of Health (NIH) reported on May 11, 2021 that research has found that an investigational gene therapy developed by researchers from the University of California, Los Angeles and Great Ormond Street Hospital in London can restore the immune systems of infants and children who have severe combined immunodeficiency due to adenosine deaminase deficiency (ADA–SCID), a rare, life-threatening inherited immunodeficiency disorder.

Caused by mutations in the ADA gene that impair the activity of the adenosine deaminase enzyme needed for healthy immune system function, ADA–SCID is often treated with enzyme replacement therapy, which does not reconstruct immune function, must be taken once or twice weekly, and requires a genetically matched donor, NIH said in a company press release. The new research evaluated the gene therapy by implanting a normal copy of the ADA gene into the patient’s own blood-forming stem cells. Then, a vector delivered the normal ADA gene to these cells in the laboratory and the genetically corrected stem cells are infused back into the patient, who has received a low dose of the chemotherapy medication busulfan to let the cells establish themselves in the bone marrow and begin producing new immune cells.

Phase I/II clinical trials conducted in the United States and the United Kingdom showed the gene therapy to be safe overall, with some participants experiencing mild or moderate side effects attributed to the chemotherapy they received.

“These findings suggest that this experimental gene therapy could serve as a potential treatment option for infants and older children with ADA–SCID,” said Anthony S. Fauci, MD, director of NIH’s National Institute of Allergy and Infectious Diseases, in the press release. “Importantly, gene therapy is a one-time procedure that offers patients the hope of developing a completely functional immune system and the chance to live a full, healthy life.”

Source: NIH