Glenzocimab fails to improve outcomes in acute ischemic stroke thrombolysis

BACKGROUND: Glenzocimab, a platelet glycoprotein VI antagonist, is a novel agent that inhibits platelet activation and aggregation. Its safety was demonstrated in the ACTIMIS trial (Acute Ischemic Stroke Interventional Study; URL: https://www.clinicaltrials.gov; Unique identifier: NCT03803007) for patients with stroke receiving thrombolysis, with or without mechanical thrombectomy, and results suggested a reduction in intracranial hemorrhages and mortality. The ACTISAVE trial was designed as a confirmatory study to evaluate the efficacy and safety of glenzocimab in acute ischemic stroke. METHODS: ACTISAVE (Acute Ischemic Stroke Study Evaluating Glenzocimab Used as Add-On Therapy Versus Placebo) was an international, randomized, double-blind, placebo-controlled phase 2/3 study in patients with stroke, treated by thrombolysis within 4.5 hours of symptoms onset with or without mechanical thrombectomy. The study was conducted at 54 primary and comprehensive stroke centers located in 10 countries. Patients were randomized 1:1 to glenzocimab (1000 mg-IV) or placebo. The primary outcome was the modified Rankin Scale (mRS) score of 4 to 6 at day 90. Key secondary outcome was the mRS score of 0 to 2 at day 90. Mortality, mRS shift, National Institutes of Health Stroke Scale score, quality of life, and safety outcomes were assessed. RESULTS: Between September 2021 and October 2023, 438 patients were randomized, 421 treated, and included as randomized in the primary analysis set. Median age was 73 (63-80) years, and 43% were female. Thrombolysis was performed 2.3 hours (median) after symptom onset and followed by mechanical thrombectomy in 36% of patients. The assigned treatment began a median of 1.2 (interquartile range, 0.8-1.6) hours after thrombolysis initiation. Prethrombolysis National Institutes of Health Stroke Scale score median was 9 (6-15). At day 90, there was no statistically significant difference in the primary outcome between the treatment groups: the incidence of poor outcome (mRS score 4-6 versus 0-3) was 21.6% in the glenzocimab group compared with 15.3% placebo group (odds ratio, 1.51 [95% CI, 0.90-2.54]; =0.120). No statistically significant difference in secondary outcomes was observed. There were no major safety signals with any intracerebral hemorrhage occurring respectively in 60 (28.6%) and 63 (29.9%) patients in glenzocimab and placebo arms. CONCLUSIONS: ACTISAVE failed to confirm a beneficial effect of glenzocimab on mRS in patients with acute ischemic stroke treated by thrombolysis. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05070260.