Asundexian Prevents Secondary Stroke Without Raising Bleeding Risk

Factor XIa inhibitor shows promise for patients with noncardioembolic ischemic stroke or high-risk transient ischemic attack

Published on Feb. 6, 2026

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In the phase 3 OCEANIC-STROKE trial, the factor XIa inhibitor asundexian reduced the risk of secondary stroke in patients with noncardioembolic ischemic stroke or high-risk transient ischemic attack, without increasing the risk of bleeding compared to placebo. The results were consistent across all subgroups, representing a potential "paradigm shift" in stroke prevention.

Why it matters

Current antiplatelet therapies have struggled to prevent secondary strokes without increasing bleeding risk. The positive results of the OCEANIC-STROKE trial suggest asundexian could provide a new treatment option that effectively prevents recurrent strokes while maintaining safety, which could have a significant impact on the 5.5 million patients who experience noncardioembolic ischemic strokes globally each year.

The details

The OCEANIC-STROKE trial randomly assigned 12,327 patients within 72 hours of acute noncardioembolic ischemic stroke or high-risk TIA to once-daily asundexian 50 mg or placebo, both on top of antiplatelet therapy. During 31 months of follow-up, participants assigned asundexian experienced a 26% lower risk of secondary ischemic stroke compared to placebo (HR=0.74, p<0.001). There was no significant difference in the risk of the primary safety outcome of major bleeding between the two groups (HR=1.1, 95% CI 0.85-1.44).

  • The OCEANIC-STROKE trial enrolled patients within 72 hours of acute noncardioembolic ischemic stroke or high-risk TIA.
  • Participants were followed for 31 months after the index stroke event.

The players

Ashkan Shoamanesh, MD

Stroke neurologist at McMaster University in Hamilton, Ontario, Canada, senior scientist at the affiliated Population Health Research Institute, and co-principal investigator of the OCEANIC-STROKE study.

Asundexian

A factor XIa inhibitor developed by Bayer that was evaluated in the OCEANIC-STROKE trial for the prevention of secondary stroke.

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What they’re saying

“What makes me believe this is a revolutionary paradigm shift in our ability to prevent stroke is the safety results that came with this improved efficacy, because we saw these benefits without any excess in our primary safety endpoint.”

— Ashkan Shoamanesh, MD, Stroke neurologist and co-principal investigator (Healio)

“This is the first case in history where an anticlotting drug is able to prevent a clotting event without having some offsetting harm from bleeding.”

— Ashkan Shoamanesh, MD, Stroke neurologist and co-principal investigator (Healio)

What’s next

The positive results from the OCEANIC-STROKE trial will likely lead to regulatory submissions for asundexian as a new treatment option to prevent secondary stroke in patients with noncardioembolic ischemic stroke or high-risk transient ischemic attack.

The takeaway

The OCEANIC-STROKE trial represents a potential "paradigm shift" in stroke prevention, as asundexian was able to significantly reduce the risk of recurrent stroke without increasing the risk of bleeding complications. If approved, this factor XIa inhibitor could provide a new and effective treatment option for the millions of patients who experience noncardioembolic ischemic strokes each year.