26% fewer second strokes, $748.50 a month, and a new class of blood thinner that has to earn its place

Survive a stroke and the next worry is the second one. Even with the best guideline treatment, up to 20% of patients with a non-cardioembolic ischaemic stroke have another within five years, says Ashkan Shoamanesh of McMaster University, co-principal investigator of the trial behind Monday’s approval². The tools to push that number down have always run into the same wall: more protection against clots has meant more bleeding.

On Monday the US Food and Drug Administration approved Bayer’s Sunharbo (asundexian), 50 mg tablets taken once a day, the first of a new class of anticoagulants called factor XIa inhibitors¹. It is licensed alongside antiplatelet therapy for adults after a recent mild-to-moderate ischaemic stroke whose clot did not come from the heart, or after a high-risk transient ischaemic attack, the “mini-stroke”¹. It is not approved for patients with atrial fibrillation¹.

The evidence is the sort institutions should want. OCEANIC-STROKE was randomised, double-blind and placebo-controlled, with 12,327 adults started within 72 hours of symptoms¹. Asundexian cut the risk of ischaemic stroke by 26% against placebo over a median 14.2 months of treatment¹; TCTMD reports the absolute reduction at 2.2 percentage points through two years². Desk arithmetic: 1 ÷ 0.022 is about 45, so on those figures roughly 45 patients would need treating to prevent one stroke over that period.

The fine print matters, and the regulator printed it. Overall major bleeding was similar to placebo, but higher in patients over 75 and in the first 90 days; gastrointestinal bleeding was more common¹, at 2.7 versus 2.1 per 100 patient-years². The drug should be paused around surgery and after clot-busting treatment, and it is not recommended with moderate or severe liver impairment¹.

Then comes the dull machinery. Bayer expects to ship this month, at a list price of $748.50 for a 30-day supply, which the company says is not what most plans or patients will pay². Desk arithmetic: that is about $24.95 a day at list. Cheryl Bushnell of Wake Forest University recently told TCTMD that cost is “probably going to be the main limiting factor”². For you, the useful question is not whether this is a breakthrough. It is whether your doctor, your guideline and your insurer all reach the same answer. China approved it last month; Europe and Japan are still reviewing².