Currently, the standard-of-care for individuals living with hemophilia B is intravenous factor IX infusions (prophylaxis). These infusions can be time-consuming, require adherence to a strict schedule, and may not completely stop bleeding episodes or other hemophilia B symptoms. However, there is now a new therapy for those with this condition: HEMGENIX (etranacogene dezaparvovec-drlb). According to a late November 2022 news release from gene therapy company uniQure N.V., the FDA recently approved this gene therapy, providing an alternate therapeutic option for patients. The therapy was developed by CSL Behring, of whom uniQure is a partner, and licensed to uniQure in 2021.
Learning about Hemophilia B
As described above, hemophilia B is a rare hereditary bleeding disorder caused by clotting protein deficiency. Hemophilia A is characterized by factor VIII deficiency, while factor IX deficiency delineates hemophilia B. Those with this condition may experience prolonged bleeding following physical impacts such as accidents, dentist visits, or surgery. In people with severe hemophilia, bleeds may also occur spontaneously. Symptoms can (but do not always) include:
- Easy bruising
- Frequent nosebleeds
- Bleeding from cuts, abrasions, surgeries, etc. that last for a while
- If bleeding near joints, joint pain and swelling
- Hematuria (blood in the urine)
- Bloody stool
- Unprovoked spontaneous bleeds
- If bleeding in the brain, headaches, neck stiffness, or nausea/vomiting
What is HEMGENIX?
Approved for use in adult patients, HEMGENIX is an adeno-associated virus vector (AAV) gene therapy administered via a one-time infusion. It delivers the Padua gene variant (FIX-Padua) to patients, which helps to produce a coagulation protein called factor IX. Those with hemophilia B are factor IX-deficient. Because of this, their blood does not clot properly, which may lead to extended bleeding episodes. By delivering this gene to patients, HEMGENIX allows patients’ bodies to begin producing factor IX.
So far, HEMGENIX has shown positive results in clinical studies. 54 patients with moderate or severe hemophilia B enrolled in the Phase 3 HOPE-B study. During a six-month lead-in period, researchers evaluated bleeding rates and events for the 54 patients. Next, they were given HEMGENIX and followed for approximately 18 months (1.5 years) or longer. Findings from the study show that:
- 94% of patients were able to stop using prophylaxis therapy during the trial and did not need to return to treatment after the trial.
- Patients’ rates of bleeding annually were reduced by 54% following HEMGENIX treatment, highlighting a high level of efficacy.
- Within 6 months and 24 months (2 years) following HEMGENIX treatment, patients saw factor IX activity rise between 36.7-39%.
- HEMGENIX was relatively safe and well-tolerated. However, some adverse reactions did occur. These include nausea and general malaise, infusion-site reactions, fatigue, elevated blood and liver enzymes, and headache.
