Expanding the Window: New Trial Finds Clot-Busting Drug Helps Stroke Patients Up to 24 Hours After Onset

 For decades, the clock has been the enemy in stroke care. Every minute without treatment means more brain cells lost — and for patients who arrive at the hospital more than four and a half hours after their symptoms began, treatment options have been frustratingly limited. But a new clinical trial is challenging that boundary in a meaningful way.

What the OPTION Trial Found

Presented at the International Stroke Conference (ISC) 2026 in New Orleans, the OPTION trial tested whether intravenous tenecteplase — a clot-dissolving medication — could help patients with acute ischemic strokes caused by non-large-vessel occlusions (non-LVOs) when given between 4.5 and 24 hours after symptom onset.

The results were striking. Patients who received tenecteplase were significantly more likely to achieve an excellent functional outcome at 90 days — defined as a modified Rankin Scale score of 0 or 1 (meaning little to no disability) — compared to those who received standard care alone: 43.6% vs. 34.2%.

That's a meaningful difference in real human terms: more patients walking, talking, and living independently three months after their stroke.

Who Was in the Trial?

The trial enrolled 566 patients across 48 centers in China. Participants were adults with disabling strokes (measured by NIHSS scores), no large-vessel occlusion, and evidence of salvageable brain tissue on CT perfusion imaging. Crucially, none of them were candidates for endovascular thrombectomy — the gold-standard mechanical clot removal procedure.

The median time from last known well to treatment was 12 hours — well beyond the traditional thrombolysis window.

What About the Risks?

No treatment comes without tradeoffs. All cases of symptomatic intracranial hemorrhage (bleeding in the brain) occurred in the tenecteplase group — 2.8% versus 0% in the control arm. That's a statistically significant and clinically important difference.

However, there were no significant differences in overall mortality (5.0% vs. 3.2%) or serious systemic bleeding between the two groups at 90 days. Leading experts at ISC noted that the degree of functional benefit observed in OPTION appears to justify the relatively low rate of bleeding complications — especially given the lack of other effective options for these patients in the late time window.

The investigators did flag one important caution: two of the bleeding cases occurred in patients who had CT hypodensities larger than the imaging-defined core. Careful review of non-contrast CT scans is advisable before treating patients in this late window.

Why This Matters

More than half of all acute ischemic strokes are caused by non-LVOs. Until now, thrombolysis had only been proven beneficial within the first 4.5 hours for this group — leaving a significant population without effective late-window options.

This trial extends the evidence base considerably. As ISC Vice Chair Dr. Bijoy Menon of the University of Calgary noted, the results are "clearly positive" and represent "one more step in our effort to actually change guidelines and practice."

The Caveats

Experts were quick to acknowledge an important limitation: the OPTION trial enrolled only patients from China. While the biology of stroke is universal, factors including genetics, comorbidities, diet, and healthcare infrastructure can influence both outcomes and risk profiles. Researchers are calling for additional trials in more diverse global populations before these findings can be applied broadly with confidence.

What Comes Next

The OPTION trial findings were published simultaneously in JAMA, lending them significant weight in the medical community. If confirmed in broader populations, this research could reshape how physicians approach stroke care in the late window — offering a lifeline to patients who currently have few options once the traditional treatment clock runs out.

For now, the message is cautiously optimistic: when endovascular treatment isn't available and the right patient is identified, tenecteplase administered up to 24 hours after stroke onset may make a meaningful difference.

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Based on findings presented at the International Stroke Conference 2026 and published in JAMA, February 2026.