Researchers at Edinburgh University found that patients given the clot-busting rt-PA within six hours of a stroke were more likely to make a better recovery than those who were not.
The £5 million study, involving more than 3000 patients, was the world’s largest trial of the drug, which is given intravenously to patients who have suffered an acute ischaemic stroke.
The drug is currently licensed only for people aged under 80, but the trial found it was just as effective in older stroke victims.
Following treatment with rt-PA, scientists discovered that more stroke survivors were able to look after themselves, while a patient’s chances of making a complete recovery within six months were also increased.
An ischaemic stroke is caused by the brain’s blood supply being interrupted by a blood clot. The damage caused can be permanent or fatal.
Researchers now know that for every 1000 patients given rt-PA within three hours of a stroke, 80 more will survive and go on to live unaided. However, around one in 25 patients will die within a week of treatment because the drug can cause a secondary bleed in the brain.
But stroke experts stressed that without treatment, one third of victims would die, with another third left permanently disabled.
The findings were published in medical journal the Lancet today, alongside an analysis of all other trials of the drug from the last two decades.
Chief investigator Professor Peter Sandercock, of Edinburgh University’s Centre for Clinical Brain Sciences, said: “We know the clot-busting treatment works for a few people – younger people who get to hospital within an hour or two of having a stroke – and we wanted to find out if a wider range of people could benefit, particularly people over the age of 80 in the UK who have had a stroke.
“About 30,000 people a year over the age of 80 have a stroke in the UK, and we are not allowed to treat them because this drug isn’t licensed to use in people over 80.
“Our trial shows that it is crucial that treatment is given as fast as possible to all suitable patients.”
Professor Sandercock said the results of the study, which involved stroke patients across 156 hospitals in 12 countries between 2000 and 2011 were of “global significance”.
Around half of the people involved in the trial were over the age of 80, with just under 900 people taking part in the study within three hours of suffering a stroke, and the remainder between three and six hours.
Professor Sandercock said: “If you can get treatment within three hours, the benefits are huge. People over the age of 80 benefit as much as younger people.”
He added that there was now hope that drugs companies would seek a licence allowing the drug to be administered to stroke patients over the age of 80.
The Medical Research Council, Health Foundation UK, and Stroke Association UK funded the study.