Over 80 percent of all strokes are ischemic strokes, caused by a blood clot blocking or narrowing an artery leading to the brain. For more than 20 years, the standard of care has been the immediate administration of a drug to eliminate the clot called Alteplase (tPA).
In the largest study of its kind ever conducted in Canada, researchers at the University of Calgary and the University of Toronto found that Tenecteplase (TNK), currently used to treat heart attack, was at least as effective as tPA and probably more effective in treating ischemic strokes.
“Tenecteplase is known to be an effective drug that dissolves blood clots,” explained U of C researcher Dr. Bijoy Menon. “It’s very easy to manage, which makes it change the game when counting the seconds to rescue brain cells.”
The Alteplase study compared to Tenecteplase found that Tenecteplase (TNK), a drug used to treat heart attack, is a much more favorable treatment for ischemic stroke than tPA, as it is easier to administer.
Menon says the findings of the AcT (Alteplase vs. Tenecteplase) test were so convincing that he expects TNK to become the global standard of care in a very short time.
“The guideline committees receive the results, discuss the results and then make the transition. So I see this move going to happen in the coming months,” Menon said.
“The results are very convincing. It is quite clear at the end of the study that you now have a better choice and because of the debilitating nature of the stroke, there is an urgent need to really change care.”
The current standard of care, tPAm, is complex to administer. It takes up to an hour and requires an infusion pump to be monitored. The pump makes it more difficult to transport patients in a hospital or ambulance to a larger facility with a dedicated brain center for treatment.
By comparison, TNK is administered in a single dose via a syringe. The method reduces the weight of nurses and doctors and reduces the time from delivery of the drug. U of T researcher Dr. Rick Schwartz says it also means it will be available as a treatment in more places.
“TNK could possibly be given anywhere the patient first sees, in a medical center or a small hospital,” Schwartz explained. “One of the reasons Tenecteplase is so effective is that it can be given as a single immediate dose. This is a great advantage, saving critical time and complications.”
TNK adheres to the clot for a longer period of time than tPA, which means that blood flow is restored faster and for a longer period of time. Project lead nurse Carol Kenney says it will save lives.
“In our field we say ‘date his brain’ and every minute or second we can save in treating a patient is critical,” Kenney said. “Giving them medicine faster and trying to get rid of the clot in their brain and get them back to normal quickly is very important. It is really important for every patient.”
Stroke survivor André Lavoie, who suffered a stroke in 2015, was part of a focus team that helped guide researchers. While recovering from a stroke, Lavoa is still fully aware of the need for effective, immediate treatment.
“It’s really a breakthrough to convince people to survive, and the whole point with a stroke is: you may survive a stroke, but it ‘s the quality of life you’re looking for,” Lavoie said.
“So if you have a stroke and you can take this medicine in half an hour, it is much better than two or three hours to get it. Brain cells usually do not regenerate. So when they die, they die.”
The cross-country ActT trial included 1,600 patients at 22 primary and integrated stroke centers across Canada. The results were presented at a conference in Montreal on Wednesday and published in the medical journal The Lancet.
