Gene therapy for ADA-SCID shows promise

Research findings recently published in the New England Journal of Medicine provide hope that gene therapy may one day be an accepted treatment for ADA-SCID instead of an experimental one.

Babies born with severe combined immunodeficiency, or SCID, have no immune system and die from infection within the first year or two of life unless they undergo treatment to restore their immune system. 

The researchers, funded in part by the National Institutes of Health, found that 48 out of 50 infants and children with ADA-SCID treated with gene therapy experienced a restored immune system within a period of two to three years and did not require additional treatments. The research study took place in both the United States and the United Kingdom.

Children with ADA-SCID lack an important enzyme called adenosine deaminase (ADA), essential for the metabolic function of a variety of cells, especially T cells. The absence of this enzyme leads to an accumulation of toxic metabolic by-products within lymphocytes that cause infection-fighting cells to die.

For these most recent clinical trials, researchers used a modified lentivirus to deliver a corrected copy of the ADA gene into the patients’ stem cells. The virus, or vector, is different from the one researchers used in past gene therapy clinical trials for ADA-SCID. Prior gene therapy trials for ADA-SCID used a gamma retrovirus to transfer the gene into the stem cells, resulting in leukemia in some patients.

“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, M.D., director of NIH’s National Institute of Allergy and Infectious Diseases (NIAID).

“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.”

To learn more about the ADA-SCID gene therapy research and for a more in-depth explanation of the gene therapy process, read this news release from the National Institutes of Health.