Atopaxar, also known as E 5555 is a novel reversible protease-activated receptor-1 (PAR-1) thrombin receptor antagonist. The inhibition of thrombin-mediated platelet activation by means of protease-activated receptor-1 inhibitors represents an attractive therapeutic option for patients with atherothrombotic disease processes. In preclinical studies, atopaxar demonstrated inhibition of thrombin receptor-activating peptides (TRAP)- and thrombin-induced platelet aggregation. Atopaxar was being developed by Eisai for acute coronary syndromes (ACS) and coronary disorders, including atherothrombosis, unstable angina pectoris and myocardial infarction. Atopaxar was in phase II clinical development in the US, EU and Japan. However, development was discontinued in May 2012.

Vorapaxar is a tricyclic himbacine-derived oral thrombin receptor antagonist that acts by reversible inhibition of the protease-activated receptor-1 (PAR-1). PAR-1 is expressed on platelets and its inhibition prevents platelets from aggregation. Vorapaxar is approved by FDA and is indicated for the reduction of recurring thrombotic cardiovascular events in patients with a history of myocardial infarction or with peripheral arterial disease. Vorapaxar at the same time may cause bleeding complications including intracranial haemorrhage (ICH), when compared to standard therapy alone. That is why Vorapaxar is contraindicated in patients with prior stroke, transient ischemic attack and ICH.

Atopaxar, also known as E 5555 is a novel reversible protease-activated receptor-1 (PAR-1) thrombin receptor antagonist. The inhibition of thrombin-mediated platelet activation by means of protease-activated receptor-1 inhibitors represents an attractive therapeutic option for patients with atherothrombotic disease processes. In preclinical studies, atopaxar demonstrated inhibition of thrombin receptor-activating peptides (TRAP)- and thrombin-induced platelet aggregation. Atopaxar was being developed by Eisai for acute coronary syndromes (ACS) and coronary disorders, including atherothrombosis, unstable angina pectoris and myocardial infarction. Atopaxar was in phase II clinical development in the US, EU and Japan. However, development was discontinued in May 2012.

Atopaxar, also known as E 5555 is a novel reversible protease-activated receptor-1 (PAR-1) thrombin receptor antagonist. The inhibition of thrombin-mediated platelet activation by means of protease-activated receptor-1 inhibitors represents an attractive therapeutic option for patients with atherothrombotic disease processes. In preclinical studies, atopaxar demonstrated inhibition of thrombin receptor-activating peptides (TRAP)- and thrombin-induced platelet aggregation. Atopaxar was being developed by Eisai for acute coronary syndromes (ACS) and coronary disorders, including atherothrombosis, unstable angina pectoris and myocardial infarction. Atopaxar was in phase II clinical development in the US, EU and Japan. However, development was discontinued in May 2012.

Vorapaxar is a tricyclic himbacine-derived oral thrombin receptor antagonist that acts by reversible inhibition of the protease-activated receptor-1 (PAR-1). PAR-1 is expressed on platelets and its inhibition prevents platelets from aggregation. Vorapaxar is approved by FDA and is indicated for the reduction of recurring thrombotic cardiovascular events in patients with a history of myocardial infarction or with peripheral arterial disease. Vorapaxar at the same time may cause bleeding complications including intracranial haemorrhage (ICH), when compared to standard therapy alone. That is why Vorapaxar is contraindicated in patients with prior stroke, transient ischemic attack and ICH.