KUALA LUMPUR (Nov 25): The US Food and Drug Administration (FDA) has approved a blood clot therapy that costs US$3.5 million (RM15.61 million) per dose — making it the most expensive drug in the world.

Hemgenix is a one-off intravenous treatment for hemophilia B, a disorder in which people do not produce a protein needed to create blood clots and control bleeding.

The standard treatment currently involves regular trips to the hospital for rounds of IVs that replenish levels of the missing or faulty clotting factor.

In a statement on Tuesday (Nov 22), FDA’s Center for Biologics Evaluation and Research director Peter Marks said 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,” he said.

Hemophilia B is a genetic bleeding disorder resulting from missing or insufficient levels of blood clotting factor IX, a protein needed to produce blood clots to stop bleeding.

Symptoms can include prolonged or heavy bleeding after an injury, surgery, or dental procedure. In severe cases, bleeding episodes can occur spontaneously without a clear cause.

Prolonged bleeding episodes can lead to serious complications, such as bleeding into joints, muscles or internal organs, including the brain. 

The FDA said most individuals who have hemophilia B and experience symptoms are men.

It said the prevalence of hemophilia B in the population is about one in 40,000. Hemophilia B represents about 15% of patients with hemophilia. Many women carriers of the disease have no symptoms. However, an estimated 10% to 25% of women carriers have mild symptoms. In rare cases, women may have moderate or severe symptoms. 

Treatment typically involves replacing the missing or deficient clotting factor to improve the body’s ability to stop bleeding and promote healing. Patients with severe hemophilia B typically require a routine treatment regimen of intravenous (IV) infusions of factor IX replacement products to maintain sufficient levels of clotting factor to prevent bleeding episodes.

Hemgenix is a one-time gene therapy product given as a single dose by IV infusion.

Hemgenix consists of a viral vector carrying a gene for clotting factor IX.

The gene is expressed in the liver to produce factor IX protein, to increase blood levels of factor IX and thereby limit bleeding episodes.