A landmark discovery by McCormack Pharma provides a new insight into why some patient subgroups are at increased risk of showing resistance to the popular anti-platelet drug clopidogrel (Plavix). Excitingly, the initial CEME outcomes provide evidence for the existence of a surprising relationship between a circulating marker that is typically elevated within discrete subpopulations of patients, and clopidogrel’s target, the P2Y12 platelet receptor.