The most expensive drug in the world: a new drug for gene therapy against hemophilia

Entrance to the FDA offices in Silver Spring, Maryland.AP

An innovative and effective medicine, but at a stratospheric price.

Investment by biotech companies in new gene therapies is making it possible to develop drugs for diseases that lacked adequate treatment.

However, by affecting the price of the assumed costs, they make the new compounds accessible only to a few.

Hemgenix, a gene therapy against hemophilia recently approved by the United States, has just become the most expensive drug in history: 3.5 million dollars (about 3.3 million euros).

It will be marketed by CSL Behring.

The new compound displaces Bluebird Bio's Skysona, a $3 million drug to treat adrenoleukodystrophy, a type of gene condition that damages the membrane that insulates nerve cells in the brain, as the most expensive drug.

Zynteglo, another Bluebird Bio gene therapy for the blood disorder beta-thalassemia, priced it at $2.8 million earlier this year.

Until this year, the most expensive drug was Zolgensma, a drug developed by Novartis' gene therapy division and approved in 2019 to treat spinal muscular atrophy, a group of inherited muscle diseases that cause progressive muscle degeneration and weakness, at a cost of 2.1 million dollars.

They all have in common that they are enormously expensive innovative gene therapies.

CSL argues that, despite its record price, its treatment may end up saving money because hemophilia B is a chronic disease for which conventional therapy is also very expensive and continues indefinitely.

Hemgenix will be manufactured in Lexington, Massachusetts, by uniQure NV, which sold marketing rights to CSL Behring in 2020. The high price makes it difficult for public health systems to finance the therapy.

In the United States, it will only be available to billionaires or people with extensive health insurance coverage.

On November 22, the United States drug regulatory agency (FDA) authorized the marketing of Hemgenix (etranacogene dezaparvovec), an adeno-associated viral vector that, when injected, introduces the blood component of the drug into the body. lacking in people with hemophilia.

The FDA has approved its use for the treatment of adults with hemophilia B (congenital deficiency of factor IX, a protein needed to produce blood clots that stop bleeding) who are currently using factor IX prophylactic therapy, or who are presenting with life-threatening bleeding or bleeding episodes. severe and repeated spontaneous

majority of men

The majority of individuals with hemophilia B who experience symptoms are male.

Symptoms may include prolonged or heavy bleeding after an injury, surgery, or dental procedure;

in severe cases.

Bleeding episodes can also occur spontaneously without a clear cause and when prolonged can lead to serious complications, such as bleeding into joints, muscles, or internal organs, including the brain.

Hemophilia B affects approximately one in 40,000 people.

Some 16,000 people in the United States and Europe have it, according to uniQure.

Hemophilia B accounts for about 15% of hemophilia patients.

Hemgenix is ​​a one-time intravenous administration of a gene therapy product.

Conventional treatment now usually consists of administering, also intravenously, replacement products for the absent or deficient clotting factor to improve the body's ability to stop bleeding and promote healing.

“CSL is committed to providing innovative and pioneering solutions to address unmet medical needs, and we are proud to introduce the next wave of innovative medicines for people living with hemophilia B,” Paul Perreault, CEO, said in a statement. of King of Prussia, Pennsylvania-based biotech CSL.

The safety and efficacy of Hemgenix were evaluated in two clinical trials in men 18 to 75 years of age with severe or moderately severe haemophilia B.

Efficacy was measured by the decrease in the annualized bleeding rate (ABR) for men.

In one study, involving 54 participants, subjects had increases in Factor IX activity levels, a decreased need for routine Factor IX replacement prophylaxis, and a 54% reduction in ABR compared to baseline. .

“Gene therapy for hemophilia has been on the horizon for more than two decades.

Despite advances in the treatment of hemophilia, the prevention and treatment of bleeding episodes can negatively affect people's quality of life," said Dr. Peter Marks, director of the Center for Hemophilia Evaluation, in a statement. and FDA Biological Research.

"The approval provides a new treatment option for patients with hemophilia B and represents important progress in the development of innovative therapies for those who experience a high burden of disease associated with this form of hemophilia."

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