The humanized platelet glycoprotein VI Fab inhibitor EMA601 protects from arterial thrombosis and ischaemic stroke in mice.

Autor:	Navarro S; Institute of Experimental Biomedicine I, Josef-Schneider-Straße 2, 97080 Würzburg, Germany.; Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Wuerzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany., Talucci I; Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Wuerzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany.; Department of Neurology, University Hospital Würzburg, Josef-Schneider-Str. 11, 97080 Würzburg, Germany., Göb V; Institute of Experimental Biomedicine I, Josef-Schneider-Straße 2, 97080 Würzburg, Germany.; Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Wuerzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany., Hartmann S; Institute of Experimental Biomedicine I, Josef-Schneider-Straße 2, 97080 Würzburg, Germany., Beck S; Institute of Experimental Biomedicine I, Josef-Schneider-Straße 2, 97080 Würzburg, Germany.; Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Wuerzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany., Orth V; EMFRET Analytics GmbH, Eibelstadt, Germany., Stoll G; Institute of Experimental Biomedicine I, Josef-Schneider-Straße 2, 97080 Würzburg, Germany., Maric HM; Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Wuerzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany., Stegner D; Institute of Experimental Biomedicine I, Josef-Schneider-Straße 2, 97080 Würzburg, Germany.; Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Wuerzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany., Nieswandt B; Institute of Experimental Biomedicine I, Josef-Schneider-Straße 2, 97080 Würzburg, Germany.; Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Wuerzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany.; EMFRET Analytics GmbH, Eibelstadt, Germany.
Jazyk:	angličtina
Zdroj:	European heart journal [Eur Heart J] 2024 Nov 14; Vol. 45 (43), pp. 4582-4597.
DOI:	10.1093/eurheartj/ehae482
Abstrakt:	Background and Aims: Glycoprotein VI (GPVI) is a platelet collagen/fibrin(ogen) receptor and an emerging pharmacological target for the treatment of thrombotic and thrombo-inflammatory diseases, notably ischaemic stroke. A first anti-human GPVI (hGPVI) antibody Fab-fragment (ACT017/glenzocimab, KD: 4.1 nM) recently passed a clinical phase 1b/2a study in patients with acute ischaemic stroke and was found to be well tolerated, safe, and potentially beneficial. In this study, a novel humanized anti-GPVI antibody Fab-fragment (EMA601; KD: 0.195 nM) was developed that inhibits hGPVI function with very high potency in vitro and in vivo. Methods: Fab-fragments of the mouse anti-hGPVI IgG Emf6.1 were tested for functional GPVI inhibition in human platelets and in hGPVI expressing (hGP6tg/tg) mouse platelets. The in vivo effect of Emf6.1Fab was assessed in a tail bleeding assay, an arterial thrombosis model and the transient middle cerebral artery occlusion (tMCAO) model of ischaemic stroke. Using complementary-determining region grafting, a humanized version of Emf6.1Fab (EMA601) was generated. Emf6.1Fab/EMA601 interaction with hGPVI was mapped in array format and kinetics and quantified by bio-layer interferometry. Results: Emf6.1Fab (KD: 0.427 nM) blocked GPVI function in human and hGP6tg/tg mouse platelets in multiple assays in vitro at concentrations ≥5 µg/mL. Emf6.1Fab (4 mg/kg)-treated hGP6tg/tg mice showed potent hGPVI inhibition ex vivo and were profoundly protected from arterial thrombosis as well as from cerebral infarct growth after tMCAO, whereas tail-bleeding times remained unaffected. Emf6.1Fab binds to a so far undescribed membrane proximal epitope in GPVI. The humanized variant EMA601 displayed further increased affinity for hGPVI (KD: 0.195 nM) and fully inhibited the receptor at 0.5 µg/mL, corresponding to a >50-fold potency compared with ACT017. Conclusions: EMA601 is a conceptually novel and promising anti-platelet agent to efficiently prevent or treat arterial thrombosis and thrombo-inflammatory pathologies in humans at risk. (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)
Databáze:	MEDLINE
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