Hemophilia A is an inherited (genetic) disease where a protein, factor VIII (FVIII), which
promotes blood clotting is missing or does not work properly. Individuals with hemophilia A
are at risk for bleeding. Bleeding is prevented and/or treated with recombinant factor VIII
(rFVIII), which is an FDA-approved treatment for Hemophilia A. Obesity is common among
patients with hemophilia. Some studies have shown that obese hemophilia patients may be able
to prevent bleeding with a lower dose of clotting factor than the dose they are currently
receiving. The lower dose is calculated based on what a patient should weigh rather than what
he does weigh. This is a clinical research study to test whether calculating rFVIII dosing
based on lean body mass and ideal body weight (what a person should weigh based on his
height) in overweight and obese patients with hemophilia is more accurate than calculating
rFVIII dosing based on what a person actually weighs.