Ellis Neufeld, MD, PhD, is a hematologist at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center.
From new longer-acting drugs to promising gene therapy trials, much is changing in the treatment of hemophilia, the inherited bleeding disorder in which the blood does not clot. Hemophilia Awareness Month comes at a time of both progress and remaining challenges.
1. Many more treatment products are being introduced, including some that last longer.
People with hemophilia lack or have defects in a “factor”—a blood protein that helps normal clots form. Of the approximately 20,000 people with hemophilia in the U.S., about 80 percent have hemophilia A, caused by an abnormally low level of factor VIII, and most of the rest have hemophilia B, caused by abnormally low levels of factor IX. Many patients with severe hemophilia give themselves prophylactic IV infusions of the missing factor to prevent bleeding (which otherwise can lead to crippling joint disease when blood seeps into the joint and enzymes released from blood cells erode the cartilage).
Hemophilia factors traditionally have such a short half-life that we tend to treat patients every other day with factor VIII and twice a week with factor IX. The first two longer-lasting products came onto the market within the past year, and more are on the way. So now, with factor IX, it is possible to get an infusion just once a week and not bleed. This is really changing how we think about the disease. So far, the longer-acting factor VIII products are not yet long-lasting enough to make as dramatic a difference in the frequency of infusions. And creating really long-acting factors remains a challenge. …