Targeting GPVI with glenzocimab in COVID-19 patients: Results from a randomized clinical trial.

BACKGROUND: Glenzocimab is a novel antithrombotic agent which targets platelet glycoprotein VI (GPVI) and does not induce haemorrhage. SARS-CoV-2 triggers a prothrombotic state and lung injury whose mechanisms include coagulopathy, endothelial dysfunction, and inflammation with dysregulated platelets. METHODS AND PATIENTS: GARDEN was a randomised double-blind, exploratory phase II study of glenzocimab in SARS-CoV-2 respiratory failure (NCT04659109). PCR+ adults in Brazil and France (7 centres) were randomized to standard-of-care (SOC) plus glenzocimab (1000 mg/dayx3 days) or placebo, followed for 40 days. Primary efficacy endpoint was clinical progression at Day 4. All analyses concerned the intention-to-treat population. RESULTS: Between December 2020 and August 2021, 61 patients received at least one dose (30 glenzocimab vs 32 placebo) and 58 completed the study (29 vs 29). Clinical progression of COVID-19 ARDS was not statistically different between glenzocimab and placebo arms (43.3% and 29.0%, respectively; p = 0.245). Decrease in the NEWS-2 category at D4 was statistically significant (p = 0.0290) in the glenzocimab arm vs placebo. No Serious Adverse Event (SAE) was deemed related to study drug; bleeding related events were reported in 6 patients (7 events) and 4 patients (4 events) in glenzocimab and placebo arms, respectively. CONCLUSIONS: Therapeutic GPVI inhibition assessment during COVID-19 was conducted in response to a Public Health emergency. Glenzocimab in coagulopathic patients under therapeutic heparin was neither associated with increased bleeding, nor SAE. Clinical impact of glenzocimab on COVID-19 ARDS was not demonstrated. A potential role for GPVI inhibition in other types of ARDS deserves further experimentation. Glenzocimab is currently studied in stroke (ACTISAVE: NCT05070260) and cardiovascular indications.

Safety and efficacy of platelet glycoprotein VI inhibition in acute ischaemic stroke (ACTIMIS): a randomised, double-blind, placebo-controlled, phase 1b/2a trial.

BACKGROUND: Antagonists of glycoprotein VI-triggered platelet activation used in combination with recanalisation therapies are a promising therapeutic approach in acute ischaemic stroke. Glenzocimab is an antibody fragment that inhibits the action of platelet glycoprotein VI. We aimed to determine and assess the safety and efficacy of the optimal dose of glenzocimab in patients with acute ischaemic stroke eligible to receive alteplase with or without mechanical thrombectomy. METHODS: This randomised, double-blind, placebo-controlled study with dose-escalation (1b) and dose-confirmation (2a) phases (ACTIMIS) was done in 26 stroke centres in six European countries. Participants were adults (≥18 years) with disabling acute ischaemic stroke with a National Institutes of Health Stroke Scale score of 6 or higher before alteplase administration. Patients were randomly assigned treatment using a central electronic procedure. Total administered dose at the end of the intravenous administration was 125 mg, 250 mg, 500 mg, and 1000 mg of glenzocimab or placebo in phase 1b and 1000 mg of glenzocimab or placebo in phase 2a. Treatment was initiated 4·5 h or earlier from stroke symptom onset in patients treated with alteplase with or without mechanical thrombectomy. The sponsor, study investigator and study staff, patients, and central laboratories were all masked to study treatment until database lock. Primary endpoints across both phases were safety, mortality, and intracranial haemorrhage (symptomatic, total, and fatal), assessed in all patients who received at least a partial dose of study medication (safety set). The trial is registered on ClinicalTrials.gov, NCT03803007, and is complete. FINDINGS: Between March 6, 2019, and June 27, 2021, 60 recruited patients were randomly assigned to 125 mg, 250 mg, 500 mg, or 1000 mg glenzocimab, or to placebo in phase 1b (n=12 per group) and were included in the safety analysis. Glenzocimab 1000 mg was well tolerated and selected as the phase 2a recommended dose; from Oct 2, 2020, to June 27, 2021, 106 patients were randomly assigned to glenzocimab 1000 mg (n=53) or placebo (n=53). One patient in the placebo group received glenzocimab in error and therefore 54 and 52, respectively, were included in the safety set. In phase 2a, the most frequent treatment-emergent adverse event was non-symptomatic haemorrhagic transformation, which occurred in 17 (31%) of 54 patients treated with glenzocimab and 26 (50%) of 52 patients treated with placebo. Symptomatic intracranial haemorrhage occurred in no patients treated with glenzocimab compared with five (10%) patients in the placebo group. All-cause deaths were lower with glenzocimab 1000 mg (four [7%] patients) than with placebo (11 [21%] patients). INTERPRETATION: Glenzocimab 1000 mg in addition to alteplase, with or without mechanical thrombectomy, was well tolerated, and might reduce serious adverse events, intracranial haemorrhage, and mortality. These findings support the need for future research into the potential therapeutic inhibition of glycoprotein VI with glenzocimab plus alteplase in patients with acute ischaemic stroke. FUNDING: Acticor Biotech.

Safety and Tolerability, Pharmacokinetics, and Pharmacodynamics of ACT017, an Antiplatelet GPVI (Glycoprotein VI) Fab.

Objective- ACT017 is a novel, first in class, therapeutic antibody to platelet GPVI (glycoprotein VI) with potent and selective antiplatelet effects. This first-in-human, randomized, placebo-controlled phase 1 study was conducted to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of ACT017 in healthy subjects. Approach and Results- Six cohorts of 8 healthy male and female subjects each received ascending single doses of ACT017 (n=6) or placebo (n=2) as a 6-hour intravenous infusion, with » of the total dose administered within 15 minutes and the rest of the dose (¾ of the total dose) administered within 5 hours and 45 minutes. The 6 investigated doses ranged from 62.5 to 2000 mg. All doses of ACT017 were well tolerated, and no serious adverse events occurred during the study. None of the subjects reported an infusion site reaction. Template bleeding time was not affected in a clinically significant manner by any of the ACT017 doses. Plasma concentrations, determined by liquid chromatography-tandem mass spectrometry, increased linearly with the dose received as were the established pharmacokinetics values. There was no change in the platelet count, platelet GPVI expression assessed by flow cytometry, or plasma levels of soluble GPVI assessed by ELISA. In contrast, administration of ACT017 inhibited collagen-induced platelet aggregation measured by light transmission aggregometry on platelet-rich plasma, and the extent and duration of the effect were dose-dependent. Conclusions- The novel antiplatelet agent ACT017 has consistent pharmacokinetic/pharmacodynamic properties and favorable safety and tolerability profiles warranting further clinical development.

Quality and cost assessment of a recombinant antibody fragment produced from mammalian, yeast and prokaryotic host cells: A case study prior to pharmaceutical development.

Monoclonal antibody fragments (Fab) are a promising class of therapeutic agents. Fabs are aglycosylated proteins and so many expression platforms have been developed including prokaryotic, yeast and mammalian cells. However, these platforms are not equivalent in terms of cell line development and culture time, product quality and possibly cost of production that greatly influence the success of a drug candidate's pharmaceutical development. This study is an assessment of the humanized Fab fragment ACT017 produced from two microorganisms (Escherichia coli and Pichia pastoris) and one mammalian cell host (CHO). Following low scale production and Protein L-affinity purification under generic conditions, physico-chemical and functional quality assessments were carried out prior to economic analysis of industrial scale production using a specialized software (Biosolve, Biopharm Services, UK). Results show higher titer production when using E. coli but associated with high heterogeneity of the protein content recovered in the supernatant. We also observed glycoforms of the Fab produced from P. pastoris, while Fab secreted from CHO was the most homogeneous despite a much longer culture time and slightly higher estimated cost of goods. This study may help inform future pharmaceutical development of this class of therapeutic proteins.

Design, development and characterization of ACT017, a humanized Fab that blocks platelet's glycoprotein VI function without causing bleeding risks.

Glycoprotein VI is a platelet-specific collagen receptor critical for in vivo formation of arterial thrombosis. It is also considered as an attractive target for the development of anti-thrombotic drugs because blocking glycoprotein (GP)VI inhibits platelet aggregation without inducing detrimental effects on physiologic hemostasis. Here, we present data on the identification, in vitro and ex vivo pharmacology of a humanized Fab fragment designated as ACT017. ACT017 was selected out of 15 humanized variants based upon structural and functional properties. It was produced under GMP-like conditions followed by detailed physico-chemical analysis and functional characterization indicating high antigen-binding specificity and affinity. In addition, we demonstrate, in a dose-escalation study, that ACT017 has a high capacity to specifically inhibit collagen-induced platelet aggregation ex vivo after injection to the macaque without inducing thrombocytopenia, GPVI depletion or bleeding side effects as is the case for conventional anti-platelets. Therefore, ACT017 is a promising therapeutic candidate for the development of a new generation of safe and efficient anti-thrombotic drugs.