Sunharbo stroke prevention took a big step forward on Monday, November 9, 2026, when the United States Food and Drug Administration approved Sunharbo, known by its generic name asundexian. It is the first Factor XIa inhibitor ever approved, and the first approved treatment that prevents harmful blood clots by blocking Factor XIa, a protein in the blood that helps clots form.
The drug is a 50 mg tablet taken once a day, together with antiplatelet therapy, for adults who recently had a mild to moderate non-cardioembolic ischemic stroke or a high risk transient ischemic attack, often called a mini stroke. In the large trial behind the approval, it cut the risk of another ischemic stroke by 26 percent compared with placebo.
Quick Facts
| Topic | Detail |
|---|---|
| Drug name | Sunharbo, generic name asundexian |
| Approval date | Monday, November 9, 2026 |
| Approved by | US Food and Drug Administration |
| Dose | 50 mg tablet, once daily |
| Taken with | Antiplatelet therapy |
| Who it is for | Adults after a recent mild to moderate non-cardioembolic ischemic stroke or high risk transient ischemic attack |
| How it works | Blocks Factor XIa, a clotting protein, to prevent harmful blood clots |
| First of its kind | First Factor XIa inhibitor approved |
| Trial behind it | OCEANIC-STROKE, a phase 3 trial with 12,327 adults |
| Stroke risk reduction | 26 percent lower risk of ischemic stroke versus placebo |
| Major bleeding | 1.9 percent on asundexian versus 1.7 percent on placebo, no significant increase |
| List price | 748.50 dollars for a 30 day supply |
| Approval holder | Bayer HealthCare Pharmaceuticals Inc., Whippany, New Jersey |
| Special designations | Fast Track and Priority Review from the FDA |
| Other approvals | Approved in China in October 2026, under review in Europe and Japan |
How Sunharbo Stroke Prevention Works
A stroke happens when blood flow to part of the brain is blocked, and brain cells start to die within minutes. Most strokes are ischemic strokes, which means a clot blocks a blood vessel in the brain. Preventing the next clot matters most after a first stroke, because the risk of a second stroke is highest in the weeks and months that follow.
Sunharbo works in a new way. It blocks Factor XIa, a protein that plays a role in the chain of events that leads to a blood clot. The body needs clotting to stop bleeding after an injury, but the same process turns harmful when a clot forms inside a blood vessel and blocks blood flow. By targeting Factor XIa, the drug aims to reduce the harmful clotting that leads to stroke while leaving enough of the normal clotting process in place to limit bleeding. That balance is why the trial results on bleeding mattered as much as the results on stroke prevention. Sunharbo is taken as a 50 mg tablet once a day, together with antiplatelet therapy, which helps stop platelets from sticking together and forming clots.
Who Can Take Sunharbo
The approval covers adults who recently had a mild to moderate non-cardioembolic ischemic stroke or a high risk transient ischemic attack. A non-cardioembolic stroke is a stroke caused by a clot that did not start in the heart. In the trial, mild to moderate meant a National Institutes of Health Stroke Scale score of 15 or less. That scale is a standard tool doctors use to measure stroke severity.
A transient ischemic attack, often called a mini stroke, is a brief blockage of blood flow to the brain that causes stroke like symptoms for a short time and then resolves. Even though the symptoms pass, a transient ischemic attack is a serious warning sign that calls for urgent medical care and a prevention plan. The approval covers high risk transient ischemic attacks, where the chance of a coming stroke is greatest. Sunharbo is not approved for stroke prevention in patients with atrial fibrillation, a heart rhythm problem in which clots can form in the heart. It is also not recommended in patients with moderate or severe hepatic impairment, which means liver problems that are more than mild.
What the OCEANIC-STROKE Trial Found
The approval is based on the OCEANIC-STROKE trial, a large international study designed to test whether asundexian could prevent repeat strokes. It was a multicenter, randomized, double blind, placebo controlled phase 3 study. That means patients at many hospitals and clinics were assigned by chance to receive either asundexian or a placebo, an inactive tablet, and neither the patients nor their doctors knew which one they were getting.
The trial enrolled 12,327 adults within 72 hours of a non-cardioembolic ischemic stroke or high risk transient ischemic attack. The asundexian group had 6,162 patients, and the placebo group had 6,165 patients. Enrolling people within 72 hours meant treatment started early, when the risk of a second stroke is highest. Full results were published in the New England Journal of Medicine in April 2026, in a paper by Sharma and colleagues, in volume 394, issue 15, pages 1467 to 1479. Over a median treatment period of 14.2 months, Sunharbo 50 mg once daily reduced the risk of ischemic stroke by 26 percent compared with placebo. Recurrent ischemic stroke occurred in 6.2 percent of patients on asundexian, which was 384 of 6,162 patients, compared with 8.4 percent on placebo, which was 518 of 6,165 patients. The absolute reduction was 2.2 percent. The hazard ratio was 0.74, with a 95 percent confidence interval of 0.65 to 0.84. The result matters because a 26 percent relative reduction in a trial of more than 12,000 people is the kind of result that changes how doctors think about treatment.
Safety and Bleeding Risk
Any drug that reduces clotting raises a natural question about bleeding. If the blood clots less easily, the body may also find it harder to stop bleeding after an injury or during surgery. That trade off was a key part of the OCEANIC-STROKE trial.
The trial measured major bleeding using a standard definition known as ISTH major bleeding. Major bleeding occurred in 1.9 percent of patients on asundexian and 1.7 percent on placebo. The hazard ratio was 1.10, with a confidence interval of 0.85 to 1.44. Because that confidence interval includes 1.0, the difference was not statistically significant. In plain terms, the trial did not find a clear increase in major bleeding with asundexian compared with placebo. That finding matters, because the hope for Factor XIa inhibitors has been that they could prevent harmful clots without excess bleeding. That does not mean the drug is free of risk. All blood thinners carry some bleeding risk, and patients taking Sunharbo should watch for signs of bleeding and tell their doctor about any unusual bruising, bleeding that does not stop, blood in urine or stool, or severe headache. They should also tell their doctor about all other medicines they take.
Price, Availability, and What Comes Next
Bayer said it expects to start shipping asundexian this month, with hospitals and pharmacies able to order it soon after. The list price is 748.50 dollars for a 30 day supply. That list price is not what every patient will pay. The actual cost will depend on insurance coverage, pharmacy benefits, copays, and any patient support programs that may be offered. Patients should check with their insurer and pharmacy to learn the out of pocket cost.
The FDA granted Sunharbo Fast Track and Priority Review designations. Fast Track speeds the development and review of drugs that treat serious conditions and fill an unmet medical need. Priority Review means the FDA reviewed the application faster than usual, because the drug could offer a significant improvement over existing treatments. Asundexian was also approved in China last month, in October 2026, and it is under review by regulators in Europe and Japan.
Readers who follow health news may also want to read the Eli Lilly Foundayo sleep apnea trial, the FDA GLP-1 warning on vision loss, and our guide on how to lose weight safely.
FAQs
What is Sunharbo?
Sunharbo is the brand name for asundexian, a 50 mg tablet taken once daily. It is the first Factor XIa inhibitor approved by the FDA. It blocks Factor XIa, a protein that helps blood clots form, to lower the chance of another ischemic stroke.
Who is Sunharbo approved for?
It is approved for adults after a recent mild to moderate non-cardioembolic ischemic stroke or a high risk transient ischemic attack, often called a mini stroke. It is taken once daily together with antiplatelet therapy. It is not approved for stroke prevention in patients with atrial fibrillation, and it is not recommended in patients with moderate or severe hepatic impairment.
How well does Sunharbo work?
In the OCEANIC-STROKE trial of 12,327 adults, Sunharbo reduced the risk of ischemic stroke by 26 percent compared with placebo over a median treatment of 14.2 months. Recurrent ischemic stroke occurred in 6.2 percent of patients on asundexian compared with 8.4 percent on placebo, an absolute reduction of 2.2 percent.
Does Sunharbo increase bleeding risk?
In the trial, major bleeding occurred in 1.9 percent of patients on asundexian and 1.7 percent on placebo, which was not a statistically significant increase. All blood thinners carry some bleeding risk, so patients should watch for signs of bleeding.
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Final Thoughts
The approval of Sunharbo is a real step forward for stroke prevention, and it is one that patients and families have been waiting for. A new treatment that cut repeat ischemic strokes by 26 percent in a large trial, without a clear increase in major bleeding, gives doctors a new tool at exactly the time when patients need protection most.
At the same time, this is not a drug for everyone, and it is not a cure for stroke. It is approved for a specific group, it must be taken with antiplatelet therapy, and it carries the bleeding risk that comes with any blood thinner. The price will also shape who can use it, and access will depend on insurance and support programs. Patients should talk with their doctor about whether Sunharbo fits their history, their other medicines, and their risks. This article is general information only and is not medical advice, and readers should talk to their own doctor about stroke prevention. For those who do fit the approval, Sunharbo stroke prevention offers a new and proven way to lower the chance of a second stroke.
