eXIthera’s antithrombotic/anticoagulant 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.  Factor XIa is a clinically-validated target for the prevention of thrombosis (Buller et al., 2015) by selectively inhibiting the activation of the intrinsic (contact) pathway, without impacting normal hemostasis (bleeding) through the extrinsic pathway, yielding an antithrombotic with minimal risk of bleeding.

eXIthera’s drug candidates are small molecules that are highly potent 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. 

A number of new antithrombotic drugs currently available 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 parenteral and oral compounds have the potential to address this need, and offer complementary options for both the hospital and out-patient setting.