Washington – US health regulators on Tuesday approved the first gene therapy for hemophilia, a $3.5 million one-time treatment for the blood clotting disorder. The Food and Drug Administration has approved Hemgenix, an intravenous treatment for adults with hemophilia B, the less common form of the genetic disorder that mostly affects men.
Currently, patients receive frequent, expensive intravenous doses of a protein that helps blood clot and prevent bleeding.
Pennsylvania-based drugmaker CSL Behring announced the $3.5 million price tag shortly after FDA approval, saying its drug will ultimately lower health care costs because patients will have fewer bleeding events and need fewer coagulation treatments.
According to a study cited by the National Library of Medicine, the price makes Hemgenix the most expensive drug in the world, easily surpassinggene therapy for spinal muscular atrophy (SMA), which costs about $2 million per dose and is also a one-dose drug.
Like most drugs in the US, most of the cost of the new treatment will be paid by insurers, not patients, including private and government programs.
After decades of research, gene therapies have begun to reshape the treatment of cancers and rare inherited diseases with drugs that can modify or correct mutations built into people’s genetic code. Hemgenix is the first such treatment for hemophilia, and several other drugmakers are working on gene therapies for the most common form of the disorder, hemophilia A.
“Today’s approval provides a new treatment option for patients with hemophilia B and represents significant progress in the development of innovative therapies,” said Dr. Peter Marks of the FDA.
The agency did not say how long the treatment works. But CSL Behring said patients should benefit in terms of reduced bleeding and increased clotting for years.
Hemophilia almost always affects men and is caused by mutations in the gene for a protein needed for blood clotting. Minor cuts or bruises can be life-threatening, and many people need treatments once or more a week to prevent severe bleeding. If left untreated, the condition can cause bleeding that enters the joints and internal organs, including the brain.
Hemgenix delivers a functional gene for the clotting protein to the liver, where it is produced.
Hemophilia B affects about 1 in 40,000 people and accounts for about 15% of people with the disease, according to the FDA.
The FDA said it granted approval based on two small studies, including one that showed those taking the drug had increased levels of the clotting protein, reduced need for standard treatment and a 54 percent reduction in bleeding problems.
Earlier this year, European regulators approved a similar gene therapy for hemophilia A. That drug, from pharmaceutical company BioMarin, is still under review by the FDA.