US FDA approves Pfizer's gene therapy for rare bleeding disorder

FILE PHOTO: Signage is seen outside of FDA headquarters in White Oak, Maryland

By Sriparna Roy

(Reuters) -The U.S. Food and Drug Administration approved Pfizer's gene therapy for hemophilia B on Friday, the second such therapy for the rare bleeding disorder that typically requires regular infusions of a blood-clotting protein.

People with hemophilia have a fault in a gene that regulates production of proteins called clotting factors, which can cause spontaneous as well as severe bleeding following injuries or surgery. It predominately affects males.

Pfizer's one-time therapy, branded as Beqvez, is designed to stimulate production of the protein, called factor IX (FIX), by the patient's own body instead of intravenous infusions of FIX multiple times a week or a month.

The therapy will be available by prescription to eligible patients this quarter, a company spokesperson said.

Pfizer has set a list price for Beqvez at $3.5 million in the U.S. - the same price tag as Australian drugmaker CSL Ltd's rival gene therapy Hemgenix.

Gene therapies are often pricey, and the durability of a single-dose treatment remains an open question.

High cost, logistical issues and the prospect of potential treatment advances have so far held back adoption of the first gene therapies for hemophilia.

Nigel Key, director of the Hemophilia and Thrombosis Center at the University of North Carolina said the demand for gene therapies is limited by "how satisfied they (patients) are with their current treatment...and whether they want to dive right in, which not many do".

A single dose of Pfizer's therapy was shown to work as well as standard-of-care protein infusions after a year, with bleeding completely eliminated in 60% of patients versus 29% who received infusions.

Pfizer said it will continue to monitor for long-term durability and safety of the treatment over the course of 15 years.

Hemophilia B is estimated to affect nearly 4 in every 100,000 U.S. males, while related disorder hemophilia A is estimated to affect 12 in every 100,000 U.S. males, according to government data.

(Reporting by Sriparna Roy in Bengaluru; Editing by Shailesh Kuber and Krishna Chandra Eluri)