Recombinant GPVI-Fc added to single or dual antiplatelet therapy in vitro prevents plaque-induced platelet thrombus formation

Abstract

The efficiency of current dual antiplatelet therapy might be further improved by its combination with a glycoprotein (GP) VI-targeting strategy without increasing bleeding. GPVI-Fc, a recombinant dimeric fusion protein binding to plaque collagen and concealing binding sites for platelet GPVI, acts as a lesion-focused antiplatelet drug, and does not increase bleeding in vivo. We investigated, whether GPVI-Fc added in vitro on top of acetylsalicylic acid (ASA), the P2Y antagonist ticagrelor, and the fibrinogen receptor antagonist abciximab alone or in combination would increase inhibition of platelet activation by atherosclerotic plaque. Under static conditions, GPVI-Fc inhibited plaque-induced platelet aggregation by 53 %, and increased platelet inhibition by ASA (51 %) and ticagrelor (64 %) to 66 % and 80 %, respectively. Under arterial flow, GPVI-Fc inhibited plaque-induced platelet aggregation by 57 %, and significantly increased platelet inhibition by ASA (28 %) and ticagrelor (47 %) to about 81 % each. The triple combination of GPVI-Fc, ASA and ticagrelor achieved almost complete inhibition of plaque-induced platelet aggregation (93 %). GPVI-Fc alone or in combination with ASA or ticagrelor did not increase closure time measured by the platelet function analyzer (PFA)-200. GPVI-Fc added on top of abciximab, a clinically used anti-fibrinogen receptor antibody which blocks platelet aggregation, strongly inhibited total (81 %) and stable (89 %) platelet adhesion. We conclude that GPVI-Fc added on top of single or dual antiplatelet therapy with ASA and/or a P2Y antagonist is likely to improve anti-atherothrombotic protection without increasing bleeding risk. In contrast, the strong inhibition of platelet adhesion by GPVI-Fc in combination with GPIIb/IIIa inhibitors could be harmful.

ADPase CD39 Fused to Glycoprotein VI‐Fc Boosts Local Antithrombotic Effects at Vascular Lesions

“…Under flow, platelet inhibition by GPVI‐CD39 was more pronounced than adding a full ex vivo dose of the ADP receptor inhibitor ticagrelor to GPVI‐Fc: Comparing the results of the current study with those of our previous results, 150 nmol/L GPVI‐CD39 was equally effective in inhibiting plaque‐induced platelet aggregation (81% inhibition) as the combination of 150 nmol/L GPVI‐Fc with 3.82 μmol/L of the ADP receptor antagonist ticagrelor (79% inhibition). This comparison underscores the relative potency of the GPVI‐CD39 fusion protein compared with existing antiplatelet drugs.…”

Optimizing Platelet GPVI Inhibition versus Haemostatic Impairment by the Btk Inhibitors Ibrutinib, Acalabrutinib, ONO/GS-4059, BGB-3111 and Evobrutinib

“…46 GPVI-Fc did not increase bleeding in vitro, nor in mice and human volunteers in vivo even given on top of standard anti-platelet drugs (aspirin, P2Y12 receptor antagonists). 11,40,47 However, GPVI-Fc was less effective than Btk inhibitors in inhibiting plaque-induced platelet aggregation under static conditions and at low arterial shear flow in vitro, [10][11][12]48 and in contrast to Btk inhibitors has to be given intravenously.…”

“…[1][2][3][4] Btk is also expressed in platelets and involved in signal transduction of the collagen receptor glycoprotein (GP) VI. 5,6 Direct GPVI antagonists (antibodies, recombinant GPVI-Fc) preferentially inhibit platelet activation by collagenous material exposed after plaque rupture and erosion, [7][8][9][10][11] and we recently demonstrated that Btk inhibitors also selectively prevent atherosclerotic plaque-triggered platelet thrombus formation. 12 Collagen-induced platelet adhesion and aggregation under arterial flow requiring integrin α2β1 not being affected by Btk inhibitors was not inhibited.…”

Btk Inhibitors as First Oral Atherothrombosis-Selective Antiplatelet Drugs?

“…The abnormal structure of plaque collagens might explain, why plaques activate mainly GPVI and barely the integrin α2β1 on platelets: recombinant GPVI-Fc (Revacept) which binds to collagen, and anti-GPVI but not anti-integrin α2β1 antibodies inhibit plaque-induced platelet thrombus formation. [4][5][6]21,22 In flow chamber experiments using hirudin-or heparin-anticoagulated blood, anti-integrin α2β1 antibodies did not impair platelet thrombus formation on human atherosclerotic plaque homogenate from arterially flowing blood. 4,6 Similar results were observed using blood from integrin α2-deficient mice.…”