Stroke drug discovered at Toronto Western Hospital

A promising drug that could limit brain damage during strokes has finally been invented — after more than 1,000 attempts by many scientists and 15 years of work by a Toronto doctor.

In a Toronto Western Hospital lab, neurosurgeon Dr. Michael Tymianski created “NA-1,” a neuroprotectant drug shown to lessen damage caused from reduced blood flow to the brain during a stroke in both human and animal studies. A study reporting successful human trials of the drug was published online Sunday in the journal Lancet Neurology. And one showing its success in animals was published earlier this month in Science Translational Medicine.

“We are quite excited,” said Tymianski, who is also head of neurosurgery at the University Health Network and the Canadian research chair in translational stroke research. “The total number of people who could be touched by this kind of an intervention is huge. This is one of the greatest health burdens of society,” he added, noting that stroke is the No. 2 cause of death (after cardiovascular disease) and No. 1 cause of disability worldwide.

More studies are necessary before the drug could come to market, but Tymianski expects that will happen in three or four years. NA-1 works by blocking signals produced by a protein in the brain that cause cells to die during a stroke. The landmark clinical trial, led out of Calgary, involved comparing the drug to a placebo in more than 180 patients at 14 hospitals in Canada and the United States.

The patients had suffered small strokes while undergoing medical procedures to repair brain aneurysms. Those treated with NA-1 had a 50-per-cent reduction in brain damage. Patients with ruptured brain aneurysms, who are at very high risk of neurological damage, had good neurological outcomes when treated with the drug. “The results of this clinical trial represent a major leap forward for stroke research,” said Dr. Michael Hill, lead researcher on the human study “There have been over 1,000 attempts to develop such drugs, which have failed to make the leap between success in the lab and in humans,” added Hill, a neurologist in the Calgary Stroke Program at Foothills Medical Centre and University of Calgary’s Hotchkiss Brain Institute.

Tymianski studied the success of his drug on primates in his Toronto lab. Both studies were designed to be done together with results of the animal one guiding the human one. “This (human) clinical trial is, to our knowledge, the first time that a drug aimed at increasing the resistance of the brain to a stroke, has been shown to reduce stroke damage in humans. No efforts should be spared to develop it further,” Tymianski said.

Efforts are already underway to start a larger clinical trial on humans who have suffered strokes while out in the community instead of while undergoing a medical procedure. Participants would likely be given the drug en route to hospital by ambulance or in the emergency department. The drug’s benefits could also be explored for vascular dementia, Alzheimer’s disease, epilepsy and traumatic brain injury, Tymianski said. Currently, a clot-busting drug known as TPA is the only widely approved stroke therapy. It works by unblocking the arteries to the brain, but is only beneficial for some stroke victims. TPA has potentially serious side effects, including bleeding in the brain.

Metro News Canada

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