GPVI inhibition by glenzocimab synergistically inhibits atherosclerotic plaque-induced platelet activation when combined with conventional dual antiplatelet therapy

Abstract

Introduction Aspirin and a potent platelet P2Y12 inhibitor, such as prasugrel or ticagrelor, are not always sufficient to prevent thrombus formation in patients with ST-elevation MI (STEMI), leading to “slow flow” or “no reflow” effects after stenting. GPIIb/IIIa inhibitors, such as eptifibatide, may help in this setting, but are not used routinely due to their bleeding risk. GPVI has critical roles in thrombosis and a minimal role in haemostasis. Here we tested whether depletion of GPVI has effects on thrombus formation after MI in an animal model and investigated the effects of a novel platelet GPVI inhibitor, glenzocimab (a Fab fragment of a monoclonal antibody), on platelet activation and thrombus formation when combined with aspirin and ticagrelor. Methods We used intravital microscopy in a murine model of ST-elevation myocardial infarction and ischaemia-reperfusion injury to investigate microvascular thrombosis. We investigated the antithrombotic effects of adding glenzocimab (previously known as ACT017) to blood from healthy donors and 20 patients with ACS treated with aspirin and ticagrelor. We compared the effect of glenzocimab with the GPIIb/IIIa inhibitor eptifibatide ex-vivo. We stimulated platelets with collagen and atherosclerotic plaque material that was sourced from patients undergoing carotid endarterectomy. We investigated effects on platelet aggregation, spreading, signalling, adhesion, thrombin generation, thrombus formation and clot stability ex vivo. Results Genetic depletion of GPVI in an animal model of myocardial infarction reduced microvascular thrombosis. Ex vivo, aspirin and ticagrelor partially inhibited atherosclerotic plaque-induced platelet aggregation (assessed by multiple electrode aggregometry) by 48% compared to control (34±3 vs. 65±4 U; P<0.001; Figure 1). Atherosclerotic plaque-induced platelet aggregation, adhesion, secretion and activation were critically dependent on platelet GPVI activation and were potently inhibited by glenzocimab. Glenzocimab alone reduced atherosclerotic plaque-induced platelet aggregation by 75% compared to control (16±4 vs. 65±4 U; P<0.001; Figure 1) and by over 95% when combined with aspirin and ticagrelor (3±1 vs 65±4 U; P<0.001; Figure 1). Furthermore, glenzocimab provided multiple synergistic antithrombotic effects when added to the blood of aspirin and ticagrelor-treated patients with ACS ex vivo. Glenzocimab and the GPIIb/IIIa inhibitor, eptifibatide, had many similar antithrombotic effects but glenzocimab had less effect on mechanisms of general haemostasis compared to eptifibatide, as assessed by ROTEM (Figure 2). Conclusions The addition of glenzocimab to aspirin and ticagrelor provides synergistic inhibition of multiple critical mechanisms of atherothrombosis. Glenzocimab and the GPIIb/IIIa inhibitor, eptifibatide, share many similar antithrombotic effects, although glenzocimab has less impact on mechanisms involved in haemostasis compared to eptifibatide. FUNDunding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Academy of Medical Sciences UK Clinical Lecturer Starter GrantRoyal Embassy of Saudi Arabia

Anti‐GPVI nanobody blocks collagen‐ and atherosclerotic plaque–induced GPVI clustering, signaling, and thrombus formation

“…Platelet activation markers, particularly the highly GPVI‐dependent PS exposure, 40–42 were also markedly decreased on both surfaces with Nb2 treatment. This is similar to that seen with the anti‐GPVI F(ab)' fragment of mAb 9O12, 8 the precursor antibody to the humanized form ACT017 (Glenzocimab) 43 . Combined inhibition of the two main platelet integrins α2β1 and αIIbβ3 was required to produce similarly strong inhibition of thrombus formation and platelet activation, but lacked the effect on procoagulant platelet formation achieved by Nb2.…”

“…This is similar to that seen with the anti‐GPVI F(ab)' fragment of mAb 9O12, 8 the precursor antibody to the humanized form ACT017 (Glenzocimab). 43 Combined inhibition of the two main platelet integrins α2β1 and αIIbβ3 was required to produce similarly strong inhibition of thrombus formation and platelet activation, but lacked the effect on procoagulant platelet formation achieved by Nb2. As eptifibatide treatment causes excessive bleeding, 44 combined inhibition of αIIbβ3 and α2β1 would not be a viable treatment strategy to prevent thrombus formation.…”

Pharmacological Inhibition of Glycoprotein VI- and Integrin α2β1-Induced Thrombus Formation Modulated by the Collagen Type

“…31 In vitro studies have indicated that 9O12-Fab, as well as its derivative ACT017, suppresses collagen-and fibrin-induced platelet aggregation and thrombus formation under flow. 17,32,33 Importantly, the 9O12-Fab was found to interfere with all GPVI-induced platelet responses, including the surface expression of P-selectin and phosphatidylserine. 32 A similar suppression of collagen-induced platelet activation can be achieved by targeting the protein tyrosine kinase cascade downstream of GPVI, e.g., utilizing the Syk-kinase inhibitor PRT-060318.…”

Comparison of the Efficiency of Ultrafiltration, Precipitation, and Ultracentrifugation Methods for Exosome Isolation

“…In fact, targeted drug delivery using exosomes has been developed especially in drug delivery to tumor cells and heart tissues. Tumor cells can change their microenvironment by using exosome communication between cells and the immune system [12][13][14][15]. Acquired exosomes from liquid biopsies are not invasive and therefore have potential for the development of genomic and proteomic research for disease diagnosis and prognosis monitoring.…”