Clot-Stopping Antibody May Lessen Bleeding Risk

Anticoagulants, drugs that prevent blood clot formation, are some of the most commonly prescribed medications. These drugs reduce the risk of heart attacks and strokes but have a trade-off: They increase the risk of excessive bleeding. Physicians also administer the drugs during surgeries such as heart bypasses, where blood must flow smoothly through an artificial circuit outside the body. Excess bleeding in that situation is a thorny problem. Now, a team from Germany, Australia, and Sweden has developed an antibody that they say can stop blood clots without causing abnormal bleeding (Sci. Transl. Med. 2014, DOI: 10.1126/scitranslmed.3006804). The antibody, called 3F7, inhibits factor XIIa, a serine protease enzyme in the complex biochemical pathway that triggers clot formation. Thomas Renné of the Karolinska Institute and University Hospital, Stockholm, and colleagues tested 3F7 in rabbits. Compared with heparin, a commonly used anticoagulant, 3F7 was equally good at preventing clots and better at controlling excess bleeding.