The Food and Drug Administration has awarded King of Prussia-based CSL Behring marketing approval for Hemgenix, the first hemophilia B gene therapy to treat adults, writes John George for the Philadelphia Business Journal.

The one-time gene therapy that has been approved to treat the chronic bleeding disorder will have a list price of $3.5 million. The high price makes Hemgenix the most expensive one-time gene therapy treatment.

“We are confident this price point will generate significant cost savings for the overall health care system and significantly lower the economic burden of hemophilia B by reducing annual bleed rates, reducing or eliminating prophylactic therapy, and generating elevated FIX levels that last for years,” said the company.

FIX (Factor IX) levels are a measure of the presence of enzymes necessary for coagulation.

CSL Behring determined the price “…with consideration of the clinical, societal, economic, and innovative value represented by this novel gene therapy and was designed to support patient access to this new treatment paradigm.”

The company is aiming to make its newest treatment available to eligible people as soon as possible.

The approval of Hemgenix was hailed as a milestone in hemophilia B treatment by the Coalition for Hemophilia B.

Read more about CSL Behring in the Philadelphia Business Journal.