Hemgenix (etranacogene dezaparvovec), an adeno-associated virus vector-based gene therapy, has been approved by the U.S. Food and Drug Administration for the treatment of adults with Haemophilia B (congenital factor IX deficiency) who are currently receiving Factor IX prophylaxis therapy, have experienced recent or past life-threatening hemorrhage, or have had recurrent, severe spontaneous bleeding episodes.
“Gene therapy for hemophilia has been on the horizon for more than two decades. Despite advancements in the treatment of hemophilia, the prevention and treatment of bleeding episodes can adversely impact individuals’ quality of life”, “Today’s approval provides a new treatment option for patients with Hemophilia B and represents important progress in the development of innovative therapies for those experiencing a high burden of disease associated with this form of hemophilia.”
Peter Marks, M.D., Ph.D., Director of the FDA’s Center for Biologics Evaluation and Research
Blood clotting factor IX, a protein required to build blood clots to halt bleeding, is either absent or present in insufficient amounts in people with haemophilia B, a genetic bleeding condition. After an injury, surgery, or dental operation, there may be prolonged or substantial bleeding as a symptom. In more serious circumstances, spontaneous bleeding episodes may happen without a known reason. Serious complications, such as bleeding into joints, muscles, or internal organs, including the brain, can result from protracted bleeding episodes.
Men are more likely than women to develop haemophilia B and show symptoms. Hemophilia B affects roughly 15% of haemophilia patients, with an incidence of one in 40,000 in the general population. Many female carriers of the illness don’t exhibit any symptoms. However, it’s thought that 10–25% of female carriers may experience mild symptoms; very rarely, women may experience moderate or severe symptoms.
In order to improve the body’s capacity to stop bleeding and encourage healing, the clotting factor that is deficient or missing is typically replaced. To maintain adequate levels of clotting factor to stop bleeding episodes, patients with severe haemophilia B typically need a routine treatment regimen of intravenous (IV) infusions of Factor IX replacement products.
Hemgenix is a one-time gene therapy treatment administered by intravenous infusion. A viral vector called Hemgenix carries a gene for clotting factor IX. In order to manufacture more Factor IX protein, raise blood levels of the substance, and lessen bleeding episodes, the gene is expressed in the liver.
Two studies with 57 adult men aged 18 to 75 with severe or moderately severe haemophilia B examined the safety and efficacy of Hemgenix. On the basis of drops in the men’s annualised bleeding rate, effectiveness was determined (ABR). A 54-person study found that the subjects had higher levels of Factor IX activity, less need for routine Factor IX replacement prophylaxis, and a 54% drop in ABR from baseline.
Hemgenix side effects that were most frequently reported were liver enzyme increases, headaches, minor infusion-related responses, and flu-like symptoms. Blood liver enzyme increases (transaminitis) and unfavourable infusion reactions should be watched in patients.
Priority Review, Orphan, and Breakthrough Therapy designations were given to this application.
Hemgenix was approved by the FDA for CSL Behring LLC.