Real-time platelet P2Y12 receptor occupancy as a promising pharmacodynamics biomarker for bridging the gap between PK/PD of clopidogrel therapy

Clopidogrel effectively inhibits platelet aggregation in response to ADP by irreversibly binding to the platelet P2Y₁₂ receptor through its active metabolite. However, the observed discrepancies between the pharmacokinetics (PK) and pharmacodynamics (PD) of clopidogrel present substantial challenges in individualizing of antiplatelet therapy. To address these challenges, a robust liquid chromatography-tandem mass spectrometry method has been developed to facilitate the real-time assessment of platelet P2Y₁₂ receptor occupancy. This method has been validated in animal models, providing a reliable link between individual PK profiles and PD effects. Target receptor occupancy offers a comprehensive overview of interindividual variations in clopidogrel metabolism, regulation of P2Y₁₂ receptor expression, and platelet turnover. Moreover, it directly correlates with the inhibitory effect on platelet aggregation. The levels of platelet P2Y₁₂ occupancy accurately reflect the extent of clinical factors influencing the PD of clopidogrel, including dosage, drug-drug interactions (DDI), and type 2 diabetes mellitus (T2DM). As a normalized metric, platelet P2Y₁₂ occupancy not only serves potential as a diagnostic tool for personalized clopidogrel therapy but also aids in elucidating the role of the P2Y₁₂ signaling pathway in cases of abnormal on-treatment platelet reactivity.