Bayer’s Phase III OCEANIC-STROKE trial shows the Factor XIa inhibitor asundexian reduced recurrent ischemic stroke risk by 26% without increasing major bleeding, supporting its potential role in secondary stroke prevention.
Written By: Nikita Chaudhari BPharm
Reviewed By: Pharmacally Editorial Team
Bayer has reported positive topline results from the global Phase III OCEANIC-STROKE trial (NCT05686070), showing that its investigational Factor XIa inhibitor asundexian significantly reduced the risk of recurrent ischemic stroke without increasing major bleeding. Full results were presented at the International Stroke Conference 2026 in New Orleans, USA.
Commenting on the findings, principal investigator Mike Sharma, Michael G. DeGroote Chair in Stroke Prevention at McMaster University, described the results as a meaningful advance for the field. He highlighted the sustained reduction in stroke risk alongside a safety profile that did not show an increase in major bleeding, noting that such progress has been a long-standing goal in secondary stroke prevention research.
Trial design and primary outcomes
OCEANIC-STROKE was a large, randomized, double-blind, placebo-controlled Phase III study that enrolled more than 12,300 patients worldwide. The trial evaluated once-daily oral asundexian 50 mg versus placebo, with both treatments given on top of standard antiplatelet therapy, in patients who had experienced a non-cardioembolic ischemic stroke or a high-risk transient ischemic attack.
The study met its primary endpoint, demonstrating a 26 percent reduction in recurrent ischemic stroke with asundexian compared with placebo (csHR 0.74; 95% CI 0.65–0.84; p<0.0001). The treatment benefit was consistent across key prespecified subgroups, including age, sex, stroke subtype, baseline NIHSS score, use of thrombolysis, and background antiplatelet regimen, whether single or dual therapy.
OCEANIC-STROKE represents the first successfully completed Phase III trial of a Factor XIa inhibitor to demonstrate superiority over placebo in reducing recurrent ischemic stroke.
Secondary efficacy and safety findings
In secondary endpoint analysis the drug reduced the risk of any stroke, ischemic or haemorrhagic, by 26 percent compared with placebo (6.6% vs. 8.8%; csHR 0.74; 95% CI 0.65–0.84; p<0.0001). In addition, asundexian met composite secondary endpoints that included cardiovascular death, myocardial infarction, or stroke, as well as the composite of all-cause death, myocardial infarction, or stroke.
From a safety perspective, asundexian did not increase the rate of ISTH major bleeding compared with placebo (1.9% vs. 1.7%; HR 1.10; 95% CI 0.85–1.44). Rates of other prespecified bleeding endpoints were also similar between treatment groups. This balance of efficacy and safety addresses a long-standing challenge in secondary stroke prevention, where intensified antithrombotic therapy often comes at the cost of higher bleeding risk.
Broad patient population and stroke subtypes
The trial was designed to reflect real-world clinical practice and included a broad range of stroke etiologies classified according to TOAST criteria. Among enrolled patients with an index ischemic stroke, 43 percent had large-artery atherosclerosis, 23 percent small-vessel occlusion, 30 percent stroke of undetermined etiology, 3 percent other determined etiologies, and 2 percent cardioembolic stroke. Across all evaluated subtypes, recurrent ischemic stroke rates were consistently lower with asundexian than with placebo.
Drug profile and next steps
Asundexian is a once-daily, oral investigational Factor XIa inhibitor designed to reduce pathologic thrombosis while preserving normal hemostasis. Factor XIa plays a limited role in physiological clot formation but contributes to thrombus propagation, making it an attractive target for safer anticoagulant strategies.
Bayer plans to submit the OCEANIC-STROKE data to regulatory authorities to support potential marketing authorization. Asundexian has already received Fast Track Designation from the U.S. Food and Drug Administration for stroke prevention in patients after a non-cardioembolic ischemic stroke.
References
Bayer’s asundexian demonstrated a substantial, 26 percent reduction in stroke after a non-cardioembolic ischemic stroke or high-risk transient ischemic attack with no increase in ISTH major bleeding versus placebo, 05 February 2026, Bayer’s asundexian demonstrated a substantial, 26 percent reduction in stroke after a non-cardioembolic ischemic stroke or high-risk transient ischemic attack with no increase in ISTH major bleeding versus placebo
A Study to Test Asundexian for Preventing a Stroke Caused by a Clot in Participants After an Acute Ischemic Stroke or After a High-risk Transient Ischemic Attack, a So-called Mini Stroke (OCEANIC-STROKE), ClinicalTrials.gov ID NCT05686070, Study Details | NCT05686070 | A Study to Test Asundexian for Preventing a Stroke Caused by a Clot in Participants After an Acute Ischemic Stroke or After a High-risk Transient Ischemic Attack, a So-called Mini Stroke | ClinicalTrials.gov