OCEANIC-STROKE: Asundexian Achieves Primary Efficacy Endpoint in Patients with Ischemic Stroke

Asundexian, an investigational, once-daily oral FXIa inhibitor, has met its primary efficacy and safety endpoints, including reduction in ischemic stroke risk without increasing International Society on Thrombosis and Hemostasis (ISTH) major bleeding rate in patients after an acute non-cardioembolic ischemic stroke or high-risk transient ischemic attack, in the phase 3 OCEANIC-STROKE study.1

Announced on November 23, 2025, by parent company Bayer, this news comes on the heels of Bristol Myers Squibb and Johnson & Johnson cancelling their own investigative program, Liberaxia, for FXIa inhibitor milvexian for acute coronary syndrome. The collaborative program was terminated on November 14, 2025, after an interim analysis determined the trial was unlikely to meet its primary efficacy endpoint.1,2

Asundexian inhibits Factor XIa, a protein in the blood coagulation pathway that forms hemostatic plugs to seal leaks at sites of vessel injury. FXIa is also thought to contribute to the formation of pathological thrombus growth and vessel blockage. Asundexian has now proven its efficacy in reducing thrombus formation without a significant increase in major bleeding.1

“As clinicians, we see every day how devastating a recurrent stroke can be for patients and their families,” Mike Sharma, MD, director of the stroke program at Hamilton Health Sciences, Michael G. DeGroote Chair in stroke prevention at McMaster University, and principal investigator in OCEANIC-STROKE, said in a statement. “Even with currently available therapies, the risk of another stroke remains high, and each recurrence can have profound consequences. The topline results from OCEANIC-STROKE indicate that asundexian may become a new treatment option to reduce this risk, representing a potential major step forward in secondary stroke prevention.”1

The OCEANIC-STROKE trial was a multicenter, randomized, international, double-blind, parallel group, event-driven, placebo-controlled phase 3 study, conducted over 741 locations. Patients were eligible for inclusion if they were ≥18 years old, had acute non-cardioembolic stroke or high-risk TIA, and had systemic or cerebrovascular atherosclerosis or acute non-lacunar infarct. Patients who had experienced ischemic stroke ≤7 days before index, an index stroke following procedures or strokes due to other rare causes, or a history of atrial fibrillation/flutter, left ventricular thrombus, mechanic valve or other cardioembolic source of stroke requiring anticoagulation were excluded.3

A total of 12,327 patients were included in the study, who were then randomly assigned to either asundexian 50 mg once daily or placebo. The primary efficacy endpoints were time to first occurrence of ischemic stroke and time to first occurrence of ISTH major bleeding, both measured up to 31 months. Secondary outcomes included time to first occurrence of all strokes, first occurrence of a composite of cardiovascular death, myocardial infarction (MI), or stroke, first occurrence of a composite of all-cause mortality, MI, or stroke, first occurrence of transient ischemic attack, and others.3

Ultimately, investigators found a significant reduction in ischemic stroke risk with asundexian compared to placebo, both in combination with antiplatelet therapy. Additionally, participants had no increase in ISTH major bleeding risk. Detailed data from the trial will be presented at an upcoming scientific congress.1

Notably, these results also come just over 2 years after Bayer cancelled their prior investigation of asundexian compared to apixaban, the OCEANIC-AF phase 3 study, in 2023. This trial was terminated on account of a lack of efficacy.4

“We are excited by these positive topline findings, which highlight the potential of Factor Xia inhibition as a new way to help protect patients from a recurrent stroke,” Christian Rommel, PhD, head of research and development at Bayer’s Pharmaceuticals Division, said in a statement. “This marks an important milestone in Bayer’s longstanding commitment to advancing innovation in thrombosis prevention. We extend our sincere gratitude to the investigators, patients, and colleagues whose dedication made this milestone possible.”1

References

1. Bayer. Bayer’s Asundexian Met Primary Efficacy and Safety Endpoints in Landmark Phase III OCEANIC-STROKE Study in Secondary Stroke Prevention. BusinessWire. November 23, 2025. Accessed November 24, 2025. https://www.businesswire.com/news/home/20251123638167/en/Bayers-Asundexian-Met-Primary-Efficacy-and-Safety-Endpoints-in-Landmark-Phase-III-OCEANIC-STROKE-Study-in-Secondary-Stroke-Prevention

2. Bristol Myers Squibb. Update on Phase 3 Librexia ACS Trial. November 14, 2025. Accessed November 24, 2025. https://news.bms.com/news/details/2025/Update-on-Phase-3-Librexia-ACS-Trial/default.aspx

3. Bayer. 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 Identifier: NCT05686070. Updated November 12, 2025. Accessed November 24, 2025. https://www.clinicaltrials.gov/study/NCT05686070

4. Bayer // Global. OCEANIC-AF study stopped early due to lack of efficacy. November 19, 2023. Accessed November 24, 2025. https://www.bayer.com/media/en-us/oceanic-af-study-stopped-early-due-to-lack-of-efficacy/