According to the notification released on 22 November 2022, the Food and Drug Administration (FDA) has approved Etranacogene dezaparvovec (an adeno-linked viral vector-based gene therapy) to manage people with Hemophilia B (congenital Factor IX deficiency) who have repeatedly experienced major spontaneous bleeding episodes, or have experienced recent or past life-threatening hemorrhage, or are presently receiving Factor IX prophylaxis treatment. This one-time gene therapy product is administered intravenously.

For more than 20 years, hemophilia gene therapy has been significantly on the horizon. Despite improvements in hemophilia therapy, the prevention and management of bleeding episodes can negatively affect the quality of life of the patient. This approval offers a novel intervention option for the hereditary bleeding condition Hemophilia B and is a significant step in the creation of innovative treatments for people who suffer from high disease load.

Blood clotting factor IX, a protein required to build blood clots to halt bleeding, is either absent or present in inadequate amounts in people with hemophilia B. Following a dental operation, surgery, or injury, there may be prolonged or heavy bleeding as a symptom. Spontaneous bleeding episodes without a recognized cause may happen in more serious scenarios. Prolonged bleeding episodes can trigger serious complexities like bleeding into joints, muscles, or internal organs like brain.

Hemophilia B symptoms and development are more common in males than in women. About 15% of hemophilia patients have hemophilia B, which has an occurrence of one in 40,000 in the population. A large number of female carriers of the disorder don't display any symptoms. However, 10–25% of female carriers might have minor symptoms. In a few rare instances, women may develop severe or moderate symptoms.

The clotting factor that is insufficient or absent is frequently replaced in order to increase the body's capacity to promote healing and cease bleeding. For maintaining sufficient levels of clotting factor to halt bleeding episodes, subjects with severe hemophilia B frequently require a regular treatment of intravenous infusions of Factor IX replacement products. A viral vector containing a gene for the clotting Factor IX makes up Etranacogene dezaparvovec. In order to raise blood levels of Factor IX, lessen bleeding episodes, and produce more Factor IX protein, the gene is expressed in the liver.

Two trials including 57 adult males (aged 18 to 75 years) with severe to moderately severe hemophilia B assessed Etranacogene dezaparvovec's safety and efficacy. Based on the decline in the men's annualized bleeding rate (ABR), efficacy was explored. In a study with 54 patients,   individuals had higher levels of Factor IX activity, less need for regular Factor IX replacement prophylaxis, and a 54% drop in ABR contrasted with baseline.

Etranacogene dezaparvovec gene therapy was linked with a few adverse reactions, the most frequent of which were flu-like symptoms, mild infusion-related reactions, headaches, and a rise in liver enzymes. Elevations in blood liver enzymes (transaminitis) and adverse infusion responses should be routinely checked in patients.