Stroke patients who can't get to the hospital quickly enough to be eligible for the usual clot-busting treatments may soon have another option, results from a mid-stage trial suggest.

Currently available thrombolytic drugs must be given within a few hours after symptoms begin. That narrow window can rule out patients who did not, or could not, seek help promptly because they didn’t immediately recognize their symptoms, as well as those who wake up with symptoms of a stroke that may have started hours earlier.

The experimental drug being developed by Silver Creek Pharmaceuticals and dubbed scp776 inhibits apoptosis, a process in which injured cells self-destruct.

The drug keeps injured cells alive by delivering a hormone called insulin-like growth factor 1, or IGF-1, which activates the cells’ natural repair pathways.

In 119 patients who came to emergency departments on average about 12 hours after stroke onset - for whom there was no approved drug treatment - scp776 resulted in clinically meaningful improvements in outcomes compared to a placebo, researchers reported at the 2025 World Stroke Congress in Barcelona.

“It’s very promising to see a therapy that leverages the brain’s own recovery mechanisms to improve stroke outcomes in the clinic,” Silver Creek Chief Scientific Officer Kris Kuchenbecker said in a statement.

At the time of hospital discharge, or by day 7 after symptom onset, patients receiving scp776 had on average a clinically significant 2.26-point higher score on the 42-point NIH Stroke Scale compared to those who received a placebo, although the difference was just short of statistical significance.

At 90 days, the treatment had resulted in a 15% increase in the relative proportion of patients achieving functional independence, researchers reported.

The drug has received FDA Fast Track designation for acute ischemic strokes caused by blockages in the arteries that carry blood to the brain. The Food and Drug Administration awards the designation to speed development and review of treatments for serious conditions where there is an unmet need.

“Scp776 harnesses the well-understood repair power of growth factors in a targeted way, finally delivering on the vast preclinical evidence of therapeutic benefit of IGF-1,” Kuchenbecker said.