Ashkan Shoamanesh, MD, is an associate professor of medicine and the Marta and Owen Boris Chair in Stroke Research and Care at McMaster University.

Ashkan Shoamanesh, MD

Secondary Analyses of OCEANIC-STROKE Confirm Efficacy of Asundexian

Asundexian reduces stroke incidence and requires fewer interventions in patients after a non-cardioembolic 

 or high-risk transient ischemic attack (TIA), according to 4 late-breaking analyses presented at the European Stroke Organisation Conference (ESOC) 2026.

The original OCEANIC-STROKE study confirmed the efficacy of asundexian, an investigational oral Factor XIa (FXIa) inhibitor, for the prevention of ischemic stroke in patients following non-cardioembolic ischemic stroke or high-risk TIA. Despite having an overall minor role in the formation of hemostatic plugs to seal leaks at vessel injury sites, FXIa is believed to also contribute to the formation of pathological thrombus growth and vessel blockage as well.

“We’ve never had a trial previously where we’ve had such a large number of major and minor bleeds, and to see no excess risk with an antithrombotic versus placebo,” Ashkan Shoamanesh, MD, associate professor of medicine and Marta and Owen Boris Chair in Stroke Research and Care at McMaster University and co-principal investigator of the OCEANIC-STROKE trial, told 

 in an exclusive interview. “This would be the first time in history that we’ve seen this, and it really does make me hopeful about not only bringing this drug to market to implement the results we’ve seen thus far, but also what it could mean for cardiovascular disease on a broader scale.”

OCEANIC-STROKE was a phase 3, double-blind, event-driven, randomized, placebo-controlled trial conducted at 702 centers in 37 countries. Patients were eligible for inclusion if they had a non-cardioembolic ischemic stroke or high-risk TIA within 72 hours after the onset of symptoms. Those with ischemic stroke had a maximum score of 15 on the National Institutes of Health Stroke Scale (NIHSS), and high-risk TIA was defined as an ABCD2 score of 6 or 7. Patients who had undergone intravenous thrombolysis or mechanical thrombectomy were eligible if ≥24 hours had passed since treatment.

Eligible patients were randomly assigned in a 1:1 ratio to either asundexian 50 mg daily or matching placebo on top of planned dual or single antiplatelet therapy. The primary outcome was first occurrence of ischemic stroke, while secondary endpoints included any stroke, a composite of death from myocardial infarction, cardiovascular causes, or stroke, death from any cause, and TIA, among others.

A total of 12,327 patients were randomized, with 6162 receiving asundexian and 6165 receiving placebo. By the median follow-up of 567 days, a total of 1624 patients had discontinued asundexian and 1589 had discontinued placebo. Of the remainder, ischemic stroke occurred in 384 patients in the asundexian arm compared to 518 in the placebo arm (HR, 0.74; 95% CI, 0.65 to 0.84; 

In the present analyses of OCEANIC-STROKE, investigators examined several factors including the proportion of patients with a NIHSS score ≥8, the number of disabling strokes in each arm, the level of stroke severity in each arm, and the need for acute intervention in each arm. The results presented at ESOC 2026 largely supported the existing data of asundexian, reinforcing its efficacy for this population.

Key findings from these analyses included the following data:

Acute intervention: Of the ischemic strokes that did occur, 40 patients required acute intervention via intravenous thrombolysis and/or endovascular treatment in the asundexian group compared to 82 in the placebo group

Disabling/fatal stroke risk: Disabling stroke occurred in 2.1% of the asundexian group and 3%% in the placebo group (HR, 0.69; 96^ CI, 0.55-0.87)

Stroke severity: Moderate-to-high severity strokes (NIHSS ≥8) occurred in 88 patients in the asundexian group versus 157 in the placebo group

Ischemic stroke with fatal outcomes: 16 patients experienced fatal outcomes in the asundexian group versus 28 in the placebo group (HR, 0.57; 95% CI, 0.31-1.06)

With these data established and presented, Shoamanesh believes that the next step in the investigational and approval process for asundexian is confirmation of safety data.

“There’s no reason to believe that there’ll be any loss of safety over time,” Shoamanesh said. “If anything, we typically see with antithrombotics that the bleeding is front-loaded, and the further you go away from the time of initiation, the less the bleeding – that’s what the curves would suggest thus far, and that’s what we’ve seen in OCEANIC-STROKE.”

Editors’ Note: Shoamanesh reports disclosures with the Heart and Stroke Foundation of Canada, the Marta and Owen Boris Foundation, Bayer AG, Daiichi Sankyo, AstraZeneca, Octapharma, Inc., and others.

Bayer. Bayer announces new late-breaking data from OCEANIC-STROKE trial of asundexian. May 6, 2026. Accessed May 22, 2026. 

https://www.bayer.com/en/us/news-stories/data-from-oceanic-stroke-trial-of-asundexian

Sharma M, Dong Q, Hirano T, et al. Asundexian for secondary stroke prevention. 

Videos

Ashkan Shoamanesh, MD, discusses a series of abstracts presented at ESOC 2026 reinforcing asundexian’s protective effect in patients at risk of ischemic stroke or TIA.

Asundexian Reduces Stroke Incidence Without Increasing Bleeding, With Ashkan Shoamanesh, MD

Asundexian, an investigational Factor XIa inhibitor, lowers the risk of stroke in patients who recently experienced non-cardioembolic 

 or a transient ischemic attack (TIA) without increasing bleeding, according to data from OCEANIC-STROKE.

Despite secondary prevention strategies, 5.1% of patients with ischemic stroke or TIA have a recurrent stroke within 1 year – after 5 years, 22% of patients who had survived the event are disabled or dead. Dual antiplatelet therapy incompletely reduces this risk, and long-term use is associated with higher risks of major hemorrhage. FXIa inhibition approaches the condition from a new angle, potentially circumventing these issues.

“Not only are we not seeing excess in major bleeding, but we also didn’t see excess in minor bleeding,” Ashkan Shoamanesh, MD, associate professor of medicine and Marta and Owen Boris Chair in Stroke Research and Care at McMaster University, told 

 in an exclusive interview. “Although minor bleeding is a less immediate clinical consequence regarding health, it certainly still is very significant, because it results in substantial psychological distress for patients and leads to non-compliance, which leads to less efficacy. It’s frankly historic to have a trial of this size and to have confidence in the results, and to see no excess risk with an antithrombotic versus placebo.”

OCEANIC-STROKE was a phase 3, double-blind, event-driven, randomized, placebo-controlled trial conducted at 702 centers across 37 countries. Patients were eligible if they were ≥18 years old with a non-cardioembolic ischemic stroke or high-risk TIA within 72 hours after the onset of symptoms and had a plan for treatment with dual or single antiplatelet therapy. Those with a history of atrial fibrillation or other conditions with an indication for anticoagulation, active nontrivial bleeding, or a qualifying stroke related to a procedure or other specific cause were excluded.

After enrollment, patients were randomly assigned in a 1:1 ratio to either asundexian 50 mg daily or matching placebo, on top of planned dual or single antiplatelet therapy. The trial’s primary outcome was the first occurrence of ischemic stroke, which was determined to have occurred if there was a new focal neurologic deficit or clinically meaningful worsening of an existing deficit persisting for ≥24 hours. The primary safety outcome was major bleeding, including fatal bleeding, symptomatic bleeding in a critical area or organ, and clinically overt bleeding resulting in a hemoglobin reduction of ≥2 g/dL.

A total of 12,327 patients were randomized, with 6162 assigned to the asundexian group and 6165 to placebo. A total of 45 patients withdrew consent, and 39 were lost to follow-up. The mean age of the final group of patients was 68 years. 11,677 patients presented with ischemic stroke, while the remainder had TIA. Median follow-up was 567 days (interquartile range [IQR], 377-729).

Ultimately, Shoamanesh and colleagues found that ischemic stroke incidence was substantially lower in the asundexian group than the placebo group (6.2% vs 8.4%; cause-specific HR, 0.74; 95% CI, 0.65-0.84; 

 <.001). The incidence of a composite of death from cardiovascular causes, myocardial infarction, or stroke was also lower in the asundexian arm. Major bleeding incidence was similar between both arms (1.9% and 1.7%, respectively; cause-specific HR, 1.1; 95% CI, 0.85-1.44). Adverse events occurred in 69.3% of the asundexian group and 70.1% in the placebo group – serious adverse events had an incidence of 19.2% and 19.5%, respectively.

The team concluded that treatment with asundexian substantially reduced the risk of ischemic stroke and major cardiovascular events compared with placebo, without increasing the risk of major bleeding in patients. Shoamanesh and colleagues believe that these data mark the beginning of a major shift in ischemic stroke treatment, and in cardiovascular disease overall, as a result of FXIa inhibition’s success.


“I think this is just the beginning of a large paradigm shift in our treatment of patients with cardiovascular disease,” Shoamanesh said. “Certainly, to date, there have been challenges with factor XI and other disease states. But I suspect the reason for that is that we just haven’t found the right recipe yet – either with higher doses of existing agents or with combination treatments, factor XI is going to be used more widely across the spectrum of cardiovascular disease and venous thromboembolic disease.”

McMaster University. New anti-clotting medication lowers risk of stroke without added bleeding. 

. April 15, 2026. Accessed April 20, 2026. 

https://www.eurekalert.org/news-releases/1123838

Shoamanesh discusses the positive data from OCEANIC-STROKE, a phase 3 trial comparing the investigative FXIa inhibitor to placebo in patients with prior ischemic stroke.

Ashkan Shoamanesh, MD

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