eXIthera’s stroke prevention and antithrombosis drugs are based on the unique pathophysiological role of Factor XI in the initiation of intravascular thrombi without causing undue bleeding.  Factor XIa is a key player in the thrombosis pathway, but is not required for normal hemostasis.  Inhibition of Factor XIa activity has clearly demonstrated thrombosis prevention without bleeding in numerous animal studies.  Humans with genetic Factor XI deficiency display a dramatic reduction in the incidence of ischemic stroke.  In addition, these patients present little or no bleeding liabilities in spite of their deficiency. 

eXIthera’s drug candidates are small molecules that are highly potent, rapid-onset, and selective Factor XIa inhibitors.  Experiments conducted by eXIthera to date with these compounds provide evidence of safety (no effect on bleeding) and efficacy (antithrombotic); with a therapeutic window greater than 30-fold.  eXIthera believes that these drugs will be highly effective in stroke and thrombosis prevention without the bleeding liabilities of current anticoagulants. 

Recently, a number of new anti-thrombotic drugs have been approved that selectively target Factor II (thrombin) and Factor X, replacing older blood thinning drugs such as warfarin and heparin, particularly prior to surgery.  The use of these new drugs, however, is limited due to unpredictable, and difficult to manage, serious bleeding adverse events within the efficacious dose range.  There is broad consensus that using these agents is still risky and has resulted in the death of patients. As a result, there remains an unmet need for an effective anticoagulant without serious bleeding side effects.  eXIthera’s lead compounds are being developed to meet this need.