Gene Therapy Shows Promise for Hemophilia B Patients

Long-term study reveals significant benefits of AAV gene therapy.

A recent 13-year study reveals how gene therapy, utilizing a harmless virus to deliver a functional gene, can provide lasting benefits for individuals with hemophilia B. This innovative approach reduces bleeding episodes and diminishes the need for regular infusions, offering a potential new standard of care.

Understanding the Treatment

The study, published in The New England Journal of Medicine, confirms that adeno-associated virus (AAV) gene therapy can lead to a sustained increase in factor IX production. This protein is essential for blood clotting and is missing in those with hemophilia B.

Hemophilia B stems from a genetic mutation in the F9 gene, leading to a deficiency of factor IX. The research involved delivering a working copy of the F9 gene directly into the liver using a harmless virus.

“Exact quotation with Person Name bolded.”

—Person Name, Title

According to the CDC, in 2020, there were about 3,300 people living with hemophilia in the United States (Source: CDC).

Long-Term Outcomes

The study followed ten men with severe hemophilia B, who received a single dose of the experimental vector. The researchers tracked safety and effectiveness through lab tests, bleeding frequency, factor IX activity, and factor IX concentrate usage after treatment.

Over the 13-year study period, the therapy demonstrated a strong safety profile. No participants developed antibodies against the therapy or serious liver issues. In the high-dose group, factor IX levels remained steady, leading to a significant drop in bleeding. Before treatment, the median bleeding rate was 14 episodes per year; after, it dropped to about 1.5, a 9.7-fold reduction.

Seven of the ten participants no longer needed regular preventative treatment. Factor IX concentrate use also decreased significantly, marking a substantial improvement in patients’ lives.

Looking Ahead

The findings highlight that AAV gene therapy is safe and effectively reduces bleeding and medication needs in hemophilia B patients in the long term. The study’s authors stressed the importance of continued monitoring and further research to address rare risks and understand gene expression durability.