The Food and Drug Administration Thursday approved Obizur for the treatment of adults with acquired hemophilia A, a very rare and potentially life-threatening bleeding disorder that affects both men and women. Drug maker Baxter International evaluated the safety and efficacy of its biotech drug in a global, clinical trial of 29 adults treated for a serious bleeding episode. No safety concerns were identified in the trial, which demonstrated the effectiveness of the drug in all cases, with a high, 86 percent success rate in the initial episode.

What is Hemophilia A?

Acquired hemophilia A occurs when a person’s body develops antibodies directed against its own Factor VIII, a protein crucial to blood clotting. People who don't have a blood disorder have a FVIII activity of 100 percent. People who have severe hemophilia A have a FVIII activity of less than one percent. When FVIII is disabled, blood doesn’t clot as normal, and the result is excessive bleeding that can happen either spontaneously or with an injury, say, or following surgery.

Within months, Obizur will become commercially available in the United States. The drug is currently under regulatory review in Europe and Canada.

With rare exception, hemophilia occurs in men. About one in 5,000 males are born with the condition each year in America, and the number of people currently living with this condition is about 20,000 individuals. There’s no cure for the disease, and available treatments require expensive lifelong transfusions of drugs manufactured from human plasma or through advanced biotechnology.

Unlike inherited hemophilia, acquired hemophilia A is not a genetic disorder and develops in relation to other medical conditions or health states, such as cancer or pregnancy. Sometimes it’s caused when a person uses certain medications. In about half of all cases, though, no underlying cause is found.

Historically, uncontrolled bleeding has challenged the understanding of the medical profession. In 1803, John Conrad Otto published the first article recognizing that a hemorrhagic bleeding disorder primarily affected men and ran in certain families. However, inferred mentions of the bleeding disease can be traced to the Talmud and the Bible.

During the 1980s, when blood and plasma donations were not properly screened for HIV, about 90 percent of Americans with severe hemophilia became infected with AIDS. A child born with hemophilia today is likely to live a normal lifespan, according to the National Heart, Lung, and Blood Institute.