Hemophiliacs with Inhibitors: Therapeutic Options

There are about 12,000 patients in the United States with classic hemophilia. Most can be treated effectively with factor VIII concentrates, but about 15 per cent acquire specific inhibitors (antibodies) to factor VIII that may render replacement therapy with factor VIII ineffective. Thus, a suggestion made in 1972 — that "activated" prothrombin-complex concentrates (PCCs) contained a substance or substances that would "bypass" factor VIII inhibitor activity — was met with great excitement.1 These observations were followed by anecdotal reports that "unactivated" PCCs were also effective in patients with classic hemophilia inhibitors.2 Both "activated" and "unactivated" PCCs contain various amounts of . . .