This year's European Society of Cardiology (ESC) congress recounted a number of failures with respect to the treatment of acute coronary syndrome (ACS), with disappointing results reported for prasugrel in the ACCOAST trial and for otamixaban in the TAO study. However, a glimmer of hope remains for the Medicines Company's cangrelor. Cangrelor is a novel ADP receptor antagonist that differs from its currently marketed counterparts in that it is administered intravenously, conferring a more rapid onset and offset of action. A pooled analysis of cangrelor's Phase III trials presented at the ESC congress revealed that cangrelor significantly reduced the primary efficacy composite of death, myocardial infarction, ischemia driven revascularization, or stent thrombosis at 48 hours by 19% (Steg PG, 2013). As is expected for most antithrombotic therapies, these benefits were accompanied by an increase in bleeding, albeit mild. Are these results really something to get excited about when looking back at cangrelor's history? This blog briefly examines the performance of cangrelor in the trials included in the pooled analysis.
In 2006 the Medicines Company initiated two large Phase III trials for cangrelor. The CHAMPION program was created to test cangrelor versus clopidogrel within the setting of percutaneous coronary intervention (PCI). Both trials compared cangrelor to clopidogrel but were distinguished by the timing of clopidogrel administration (See Figure 1). These studies therefore partly addressed the issue of whether administration of an ADP receptor antagonist upstream of PCI was associated with better outcomes but essentially sought to find the optimal antithrombotic strategy to be used in combination with cangrelor. Importantly, both the CHAMPION-PCI and the CHAMPION-PLATFORM trial were terminated prematurely because of a lack of efficacy demonstrated by cangrelor.