Lead identification of a novel anticoagulant agent targeted against activated factor XII for the prevention of thrombosis without the risk of bleeding associated with current antithrombotics

Blood thinners that prevent dangerous clots also make patients bleed—a team at the University of Leeds is hunting for a compound that blocks clotting without that risk. Current anticoagulants, used by millions to prevent strokes and heart attacks, force a trade-off: enough drug to stop a clot can also cause uncontrolled bleeding, sometimes fatal. Patients require regular monitoring to keep that balance. The researchers aim to sidestep the problem entirely by targeting Factor XIIa, a protein that kick-starts clot formation but, based on strong evidence, is not needed for normal wound healing. Blocking it should prevent thrombosis without impairing the body’s ability to stop bleeding. With a £3,021,002 Wellcome Seeding Drug Discovery award, the team will screen for small molecules that inhibit Factor XIIa, then refine them into a daily oral pill. If successful, the drug could replace current therapies for conditions like atrial fibrillation or deep-vein thrombosis, eliminating the need for blood tests and reducing hospital visits. The work is applied drug discovery, not fundamental science—the goal is a specific medicine, not a general insight.