An investigational anti-clotting medication, asundexian, demonstrated a reduction in the risk of a second ischemic (clot-caused) stroke without raising bleeding concerns, according to a preliminary late-breaking science presentation at the American Stroke Association’s International Stroke Conference 2026. The meeting, held Feb. 4-6, 2026, in New Orleans, is a premier event for researchers and clinicians dedicated to stroke and brain health.
“Asundexian holds the potential to reduce the risk of a recurrent stroke over the long term without an increased safety risk. This is a major advance in our ability to prevent strokes in people at risk of stroke recurrence,” said Mike Sharma, M.D., M.Sc., principal investigator of the study, the Michael G. Degroote Chair in Stroke Prevention, professor of medicine at McMaster University and senior scientist at the Population Health Research Institute in Hamilton, Ontario, Canada.
According to the American Stroke Association, nearly 1 in 4 stroke survivors will have another stroke, called a secondary stroke. The 2021 guideline from the American Stroke Association recommends antithrombotic therapy for nearly all stroke survivors to prevent a second stroke. However, antiplatelet therapy like aspirin has limited effectiveness due to bleeding risks.
Asundexian is a novel investigational medication that inhibits Factor XIa (FXIa), a clotting protein involved in producing large blood clots that can block blood vessels. Unlike other anticoagulants such as rivaroxaban and apixaban, which inhibit Factor Xa, asundexian does not increase the risk of bleeding. People born with a genetic deficiency of Factor XI are known to have a lower risk of ischemic stroke and rarely have spontaneous bleeding.
The OCEANIC-STROKE study (Oral faCtorElevenAiNhibitor asundexian as novel antithrombotiC) is a Phase III international trial that included more than 12,300 stroke survivors. It investigated whether adding daily asundexian to antiplatelet therapy could reduce the risk of a new ischemic stroke without increasing bleeding. Participants had recently experienced a mild to moderate non-cardioembolic ischemic stroke or a high-risk transient ischemic attack (TIA).
Participants were randomly selected to receive either standard antiplatelet therapy plus a daily dose of asundexian or standard antiplatelet therapy plus a placebo. They were followed for 3 to 31 months. Researchers found that adding asundexian reduced the occurrence of ischemic stroke by 26% across all participant subgroups, including age, sex, cause of stroke, and severity. It also reduced the occurrence of disabling stroke and did not increase bleeding within the brain or major bleeding. Additionally, it lowered cardiovascular death, stroke of any type, heart attack, and major bleeding, indicating an overall benefit.
“Asundexian, when combined with standard antiplatelet therapy, helped reduce the chances of having another stroke without increasing the risk of bleeding. This benefit applies to all types of strokes, not just those caused by plaque build-up in large arteries,” Sharma said. “If approved by the FDA, asundexian could be widely used for patients who have had a non-cardioembolic stroke or a TIA.”
The study is limited by having relatively few participants with severe strokes. A substudy analyzing brain imaging data is ongoing. Asundexian is an investigational medication that has not been approved in any country, though the U.S. Food and Drug Administration has granted it fast-track designation for stroke prevention after ischemic stroke not caused by a clot from the heart. The study was funded by Bayer, which manufactures asundexian.
