ASH 2017: Preliminary results show gene therapy gains in SCID

Ewelina K. Mamcarz, MD, presented Dec. 10, 2017, at the American Society of Hematology's (ASH) Annual Meeting & Exposition in Atlanta, Georgia.

X-linked SCID, severe combined immunodeficiency, is an inherited condition where a person cannot produce infection-fighting cells: T-cells, B-cells and natural killer cells. It's a rare and devastating disease. Without treatment, babies born with SCID can contract infections and die by age two. The best available treatment, a stem cell transplant, is also very risk, and  approximately 30 percent who are treated with a transplant die by age 10. Studies with gene therapy, an experimental treatment, has also revealed a risk of leukemia.

At this year's ASH meeting, there has been exciting news reported on gene therapy for a variety of diseases, including our work in X-linked SCID (Abstract 523).

We've treated seven infants who were born with X-SCID with gene therapy. By using an inactive form of HIV, we inserted the corrected gene in place of the defective gene that spurs the development of X-linked SCID. We also used finely-calibrated doses of busulfan to prepare the infants’ bone marrow to receive the corrected stem cells. So far, the treatment has resulted in the development of T-cell, B-cell and natural killer cells in these patients, but without side effects.

We consider these preliminary results to be a substantial breakthrough for this disease. Five of the patients no longer have SCID precautions because their T cell numbers are normal and functioning.

If this form of gene therapy proves successful and safe, we could cure the many patients who do not have a sibling donor for a transplant, reduce dependency on immunoglobulin and avoid the risks associated with graft-versus-host disease.