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StrokeSeptember 2021Summary reviewed June 2026

A Clot-Busting Injection Helped Half of Stroke Patients Recover Independence

Researchers tested a clot-busting drug called staphylokinase against the standard treatment alteplase in stroke patients treated within 4.5 hours. Half the patients who got staphylokinase recovered well at 90 days, compared to 40% with alteplase. Serious side effects were less common with staphylokinase.

What the trial was testing

The FRIDA enrolled 336 patients with stroke. The study was sponsored by Supergene, LLC and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was a large trial designed to confirm whether the treatment works well enough for wider use. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.

What the results showed

50% of patients treated with staphylokinase had good recovery, versus 40% with standard treatment.

The Lancet. Neurology · 2021 · NCT03151993

These findings — that half of stroke patients treated with staphylokinase recovered to independence at 3 months — were published in the The Lancet. Neurology and represent the headline result of the study.

Researchers tracked outcomes across 336 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.

What this means for patients

For patients with stroke, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.

What you can do now

Staphylokinase is not yet FDA-approved in the United States. This large trial in Russia showed it worked as well as the current standard clot-buster, alteplase, and may cause fewer serious side effects. If you or a loved one has a stroke, call 911 immediately — alteplase is widely available and proven to save lives when given quickly.

Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.

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