List of NDC products with proprietary name hemlibra. This medication is used by people with a certain inherited bleeding problem (hemophilia A) to help prevent or lessen how often you have bleeding problems. Emicizumab-kxwh belongs to a class of medications known as monoclonal antibodies. It works by helping your blood to clot normally, which helps prevent bleeding due to hemophilia A. Preventing bleeding can lessen symptoms such as painful swellings, joint pain, pain with movement, and difficulty walking far.