Marketed anticoagulants including warfarin and antiplatelet therapies are used to prevent thrombosis, but they also have dose-dependent increases in the risk of major bleeding. XO1 Ltd. is developing a mAb targeting an allosteric site on thrombin that has the potential to provide anticoagulation without increasing the risk of bleeding.

"Researchers were generally resigned to the fact that it would likely be impossible to dissociate anticoagulation from bleeding risk," said XO1 CEO and Index Venture Partner David Grainger. But a chance clinical observation paired with corroborating in vivo data suggests XO1's ichorcumab might be able to separate the two effects.