I Still Have Questions About Investigational Gene Therapy for Hemophilia B
Hemophilia B and experimental gene therapy have been in the news lately. I was even surprised to hear a story on the topic while listening to my local NPR station. Hemophilia B is the less common form of the disorder that arises when a blood-clotting protein called factor IX is missing or deficient.
Treatment today involves infusion into a vein of the missing or deficient clotting factor IX. Patients with more severe bleeding tendencies infuse the clotting factor themselves. I have factor medication in my refrigerator, and I know how to infuse it. Infusions become a significant part of the lives of someone with severe hemophilia.
The investigational gene therapy known as FLT180a involves a single treatment, and if successful, removes the need for regular injections. “The treatment corrects a genetic defect that leaves people’s blood struggling to clot and stop bleeding,” the BBC reported. The experimental treatment is currently in a clinical trial phase and has had positive results. Some news outlets proclaim there might even be a cure for hemophilia B within the next three years.
How will this affect people like me? I can’t help but think about how experimental gene therapy might affect me and my mild hemophilia B. I believe that time will answer the following questions:
How will gene therapy affect women with hemophilia or people with mild or moderate forms of the disorder? So far, studies have included only men with severe hemophilia. Most women fall into the mild or moderate category.
What will it cost, and who will pay for it? Insurance approval for clotting factor medicine can be a headache. I can’t imagine my insurance company footing the bill for gene therapy.
How long will gene therapy treatment provide adequate factor levels? Studies suggest that results might last for more than three years, but the trials have only been running for a few years, so it’s uncertain. I think the answer to the cost issue will be determined by how long the treatment lasts. If gene therapy offers a lifelong cure, then for someone in their 20s, a high price tag would be less expensive than a lifetime of treatment.
What about children? I’ve read that a person treated with gene therapy could still pass the gene down to their children. Children have developing livers, which is where clotting factors are produced. I can’t imagine signing my child up for a gene therapy trial.
What about blood clots? According to data from the Phase 1/2 B-AMAZE clinical trial and extension study, recently published in The New England Journal of Medicine, one participant had abnormally high levels of factor IX, which led to a blood clot that was resolved with anti-clotting medication, according to Hemophilia News Today‘s Marisa Wexler.
I once experienced pulmonary embolisms, or blood clots in my lungs, after clotting factor treatment for major surgery. It wasn’t fun and in fact was a life-threatening event. I’ll keep my low factor levels over the threat of blood clots.
A cure within three years seems overly hopeful. There are so many questions and few answers for women with hemophilia. I think I’ll be living with hemophilia B for the foreseeable future — and that’s OK with me.