Hemophilia B Gene Therapy Clinical Trial

Nationally and internationally renowned hemophilia treatment center City of Hope has opened a new gene therapy clinical trial for treatment of hemophilia B.

The pioneering therapy, conducted in collaboration with Sangamo Biosciences, offers a novel means of treating severe hemophilia B, possibly eliminating the need to infuse intravenously and frequently with costly factor products, which is the current gold standard of treatment for bleeding disorders.

“As it is a gene defect that causes a lack of factor IX production, leading to the diagnosis of severe hemophilia B, this new treatment is designed to deliver normal factor-producing genes intravenously to the liver via specially designed vectors, or carriers, thereby improving factor production and blood clotting,” says Nadia Ewing, M.D., the director of City of Hope’s Hemophilia and Sickle Cell Program, and the principal investigator of the clinical trial. “In this way, the investigational product, called SB-FIX, aims to treat spontaneous bleeding episodes, as well as prevent recurrence of bleeding events.”

There have been three previous studies investigating the safety and efficacy of gene therapy for treatment of severe hemophilia B in 25 patients. The most recent study showed favorable results, with 40 percent of participants eliminating the need for their previous prophylactic infusion regimen.

This first-in-human study will enroll a total of 12 subjects who meet enrollment criteria, including those 18 years of age and older who have history of prior treatment with factor IX products, who are not currently receiving long-acting factor IX replacement therapy, who do not have any concurrent medical condition that would compromise study participation and who have not had previous gene therapy for the treatment of hemophilia B. Once eligibility is confirmed, subjects will be treated with one of three different doses of SB-FIX depending on timing of enrollment.

The duration of study participation is 39 months which includes about three months to screen patients and confirm eligibility for participation, treatment with the investigational gene therapy and up to three years of safety follow-up, after which subjects will be given an opportunity to participate in a long-term, follow-up study. Assessments during these visits include nonstandard-of-care specialized diagnostic procedures, which would be covered by the sponsor Sangamo.

As this is a phase 1 first-in-human safety and tolerability study, participants should not expect to see any immediate positive results from the treatment. The study is being done with the hope that gene therapy will introduce a newer and better class of treatments for bleeding disorders, but safety studies are done first to identify risks and toxicities of these investigational treatments, and to ensure as much as possible the protection and well-being of human research subjects.