Selatogrel, The Reversible And Specific P2y12 Receptor Antagonist, Does Not Interfere With Haemostasis

Abstract Background Combination of a P2Y12 receptor (P2Y12R) antagonist (clopidogrel, prasugrel, ticagrelor) with aspirin is the recommended standard of care for patients with acute coronary syndrome. Selatogrel is a reversible and potent antagonist of P2Y12R. Interestingly, in an experimental thrombosis model in rat, at equivalent antithrombotic effect, blood loss was lower in the presence of selatogrel, compared with clopidogrel or ticagrelor. Purpose To characterise the lower risk of bleeding previously observed with selatogrel Methods Mechanistic studies were performed to profile laser-induced thrombosis in wild-type and P2Y12 deficient mice with real-time intravital microscopy. Ticagrelor and clopidogrel were used as selatogrel comparators. Results Selatogrel, ticagrelor and clopidogrel dose-dependently inhibited laser-induced platelet thrombus formation. At maximal antithrombotic effect, only small mural platelets aggregates, corresponding to the haemostatic seals, were present. The phenotype of these haemostatic seals depended on the P2Y12R antagonist used. In the presence of clopidogrel or ticagrelor, the stability of haemostatic seals was reduced. In contrast, in the presence of selatogrel, the apparent stability was not disturbed. Moreover, equivalent antithrombotic dosing regimens of ticagrelor and clopidogrel interfered with laser-induced calcium mobilisation in the endothelium, restricted subsequent neutrophil adhesion and thus reduced fibrin-mediated stabilisation of the haemostatic seals in wild type mice. The effects of ticagrelor were also observed in P2Y12R-deficient mice, indicating that the effects are P2Y12R independent and off-target. In contrast, an equivalent antithrombotic dosing regimen of selatogrel did not interfere with the process of haemostasis in wild-type or P2Y12R-deficient mice. The degree of interference with the stability of the haemostatic seals correlated with the blood loss profile. The dosing regimens of clopidogrel and ticagrelor, corresponding to the equivalent antithrombotic effects, induced a more pronounced increase in blood loss than that observed with selatogrel. Conclusion Our data offer a novel mechanistic explanation for the differences in bleeding risk of clopidogrel, ticagrelor and selatogrel. Clopidogrel and ticagrelor were found to interfere with haemostasis due to off-target activities. In contrast, selatogrel did not interfere with haemostasis in wild-type and P2Y12-deficient mice, inferring that the process of haemostasis, as defined by formation of haemostatic seals, is independent of P2Y12R. In addition, our data emphasize that the absence of interference with haemostasis is paramount to preserve the advantage of P2Y12R antagonism. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Idorsia Pharmaceuticals Ltd. Allschwil, Switzerland