October 10 (HealthDay News) -- The U.S. Food and Drug Administration has approved Kogenate FS to help reduce bleeding episodes and prevent joint damage in children with hemophilia A, the most severe form of the disease.

Hemophilia occurs when a protein that's needed for blood to clot is either deficient or missing entirely. Kogenate FS is a genetically engineered version of the deficient protein, known as factor VIII. The product was first licensed by the FDA in 1993 to control bleeding during or after surgery.

Hemophilia A, which occurs almost exclusively in males, affects about 15,000 people in the United States, the agency said in a news release.

When hemophiliacs are injured, they bleed longer than people without the disorder. When bleeding occurs in the muscles and joints of hemophiliacs, they are at increased risk of joint damage.

The drug was clinically tested in 65 boys under 30 months of age with severe hemophilia A. Joint damage during a bleeding episode was sixfold lower, and the rate of bleeding was eightfold lower among boys who received the drug daily, compared with those who got the drug only during a bleeding episode, the agency said.