This is an excerpt from:
Stem Cell Therapy Debate Lives On, But Research Continues To Find Effective Applications In Immune And Organ Function
Long-Term Safety and Efficacy of Stem Cell Gene Therapy for ADA-SCID [Abstract #200]
Severe combined immunodeficiency (SCID) is caused by a severe genetic defect often found in newborns. Because the immune system is so severely compromised, exposure to even benign germs can result in serious or life- threatening infections like pneumonia, meningitis, or bloodstream infections. The condition must be diagnosed and treated quickly to prevent serious complications, and doctors continue to struggle with often ineffective treatment options. In this study, a team of Italian researchers found that the use of stem cells may effectively fight SCID caused by a deficiency of the ADA gene (adenosine deaminase), which is critical for the immune system to function properly.
Previous research has shown that immune function has improved when patients were given an autologous hematopoietic stem cell transplant (HSC), from the body’s own bone marrow, combined with the ADA gene. The current phase I/II study treated eight ADA-SCID children (ages 7-67 months) with HSC conditioned with busulfan, a treatment that helps with the engraftment process. After following patients for an average of three years, researchers have seen no adverse events related to the gene transfer. In fact, they have observed that the stem cells have successfully integrated into the patients’ marrow, giving rise to genetically repaired blood cells.
In the six children with a follow-up of more than one year, white blood cell counts progressively increased and T-cell functions normalized. In addition, tests found the presence of antigen-specific antibodies (proteins that help the immune system identify and fight bacteria and viruses). In five patients, levels were high enough to discontinue supplemental antibody treatment.
“We feel that these data confirm the safety and efficacy of gene therapy in improving immune and metabolic function in children diagnosed with this form of severe combined immunodeficiency,” said Alessandro Aiuti, MD, of the San Raffaele Telethon Institute for Gene Therapy in Italy and lead author of the study with Maria Grazia Roncarolo, MD. “This may represent a viable solution to reduce the mortality rates associated with SCID in newborns.”
At the conclusion of the study, all participants were healthy, with no severe infections, up to six years from the treatment. Researchers noted that because the ADA genes had sustained activity in the blood cells, the children’s growth and development has continued to improve.
The treatment is funded by the Italian non-profit Telethon Foundation, a major charity that raises and distributes funds in Italy for biomedical research on genetic diseases, and has recently attained Orphan Drug status from the European Medicines Agency (EMEA).