The Cambridge biotechnology company said Monday that it will make the largest donation ever of hemophilia drugs to developing nations, where the costs prevent thousands of people afflicted by the bleeding disorder from getting treatment.

Biogen Idec pledged to donate 1 billion units of clotting factor, the manufactured proteins that help prevent hemophiliacs from bleeding uncontrollably, to poor countries in Africa, Asia, and Latin America over the next 10 years. A severe hemophiliac may use up to 5,000 units of clotting factor a week.

“We’re hoping this makes a big difference,” said John Cox, Biogen Idec’s executive vice president for pharmaceutical operations and technology. “You’re talking about impacting the quality of life for tens of thousands of people.”

Biogen Idec is also hoping the donation, easily worth hundreds of millions of dollars, will help gain attention for its new drugs as it seeks to break into the market for hemophilia treatments, where competitors include New York-based Pfizer Inc. and Baxter International Inc., of Deerfiled, Ill. Biogen’s business in recent years has focused on treatments for multiple sclerosis. The donation of hemophilia drugs will help Biogen Idec make “a big splash” as it promotes its new drugs, said Dr. David Kuter, chief of hematology at Massachusetts General Hospital. “It gives Biogen a big blazing sign that, ‘We make [clotting] factor,’ ” Kuter said.

Hemophilia is an inherited disorder found mostly in boys and men that can result in long, debilitating bleeding and joint damage. People with hemophilia lack the proteins needed to control bleeding, but the missing blood-clotting factor can be replaced with manufactured products.

About 400,000 people worldwide suffer from hemophilia, yet more than 300,000 of them, mostly in poor countries, go without regular treatment, according to the World Federation of Hemophilia. Kuter said treatment is so scarce in developing nations that people with hemophilia usually don’t live into adulthood.

“When they do live, they have a miserable life,” Kuter said. “They have bleeds that immobilize them.”

In developed countries like the United States, hemophiliacs prevent serious bleeds by injecting the factor — about 2,000 units at a time — as often as two or three times a week. It can cost a few thousand dollars a week to treat the disorder, but much of that cost is covered by insurance in developed nations.

Biogen Idec’s clotting factors last longer than those made by other companies, meaning patients don’t have to inject the drug as often, clinical trials have shown. Biogen Idec’s drugs, however, are more expensive, so the overall costs of treatment are about the same.

Biogen Idec’s infusion therapy for hemophilia B, called Alprolix, received approval from the Food and Drug Administration in March and is now for sale in the United States.

Currently under FDA review, with approval expected this year, is a second treatment, Eloctate, for the more common hemophilia A, which is a deficiency of a different clotting factor than for hemophilia B. Eloctate has not been priced.

Both drugs will be included in Biogen Idec’s donation.

Biogen Idec is partnering on the donation with Swedish Orphan Biovitrum AB, or Sobi, a specialty health care company headquartered in Stockholm that will handle the distribution.