The approval by Health Canada, disclosed Friday by Biogen Idec, sets the stage for a Food and Drug Administration decision, expected next week, on whether to allow the drug, called Alprolix, into the larger US market. An estimated 4,000 people, mostly men, suffer from hemophilia B in the United States, compared with 700 in Canada, and 28,000 worldwide.

Canadian health officials have approved a Biogen Idec Inc. drug that controls and prevents bleeding in patients with hemophilia B, marking the first approval of a new hemophilia treatment in nearly two decades and the entry of the Cambridge biotech into a market beyond multiple sclerosis medicines.


Biogen Idec has also filed for approval of Alprolix with regulatory bodies in Australia and Japan.

The company has been testing a similar treatment for the more common hemophilia A, which affects about 142,000 people globally. It anticipates regulatory decisions on that drug in midyear.

“This is a new class of therapy that can decrease the burden of treatment,” said Glenn Pierce, senior vice president of hematology, cell, and gene therapies at Biogen Idec. “We are the first to bring this class to market, and it’s tremendously exciting. It helps patients lead more normal lives. It’s a major landmark in the treatment of hemophilia.”

Hemophilia B is a rare inherited disorder that impairs normal blood clotting in patients, leading to recurrent and extended bleeding that can cause pain and joint damage.

Biogen Idec, the largest Massachusetts-based biotechnology company, said it received approval in Canada to market Alprolix to adults and children over 12 years old. The drug will be given through infusions once a week or once every two weeks. Currently, patients with the bleeding disorder must take drugs that have to be injected two or three times weekly.

Scientists discovered in the 1960s that people with hemophilia had deficiencies in certain proteins that are responsible for normal blood clotting. Without those proteins, it takes longer for blood vessels to repair themselves, presenting a risk of bleeding and accumulation of blood in joints.


Early treatments involved taking proteins from the plasma of blood donors, but that proved dangerous at a time when the blood supply could be contaminated by the HIV and hepatitis B and C viruses. In the 1990s, researchers moved to create synthetic protein using recombinant DNA technology that identified and cloned genes responsible for encoding the proteins. Genetics Institute Inc., a Cambridge biotech research firm, won approval in 1997 for a drug based on that technology. It is now owned by US drug giant Pfizer Inc.

Biogen Idec’s new treatments for hemophilia A and B use a “fusing” technology to prolong the effect of the proteins introduced into patients’ blood, and were discovered in academic labs at Harvard University and Brandeis University. The treatments were in preclinical development at Syntonix Pharmaceuticals Inc., a Waltham company Biogen Idec bought in 2007.

Since then, Biogen Idec has been shepherding them through clinical trials in preparation for seeking regulatory approval.

The Cambridge company is the top seller of drugs to treat the neurodegenerative disease multiple sclerosis. It also receives revenue from sales of the cancer drug Rituxan, which it formerly comarketed with Swiss drug maker Roche AG. But approval of the hemophilia treatments — which Biogen Idec estimates will target markets totaling $7 billion annually — would boost its campaign to create a more diversified portfolio of medicines.


Robert Weisman can be reached at robert.weisman@globe.com. Follow him on Twitter @GlobeRobW.