A new study has shown that treatment with Boehringer Ingelheim and Genentech’s alteplase shows significant benefits in acute ischaemic stroke beyond the currently-approved three-hour treatment window.

Data from the ECASS 3 study, which were presented at the World Stroke Congress in Vienna and published in the New England Journal of Medicine shows that treatment with alteplase, sold in North America by Genentech as Activase and elsewhere by Boehringer as Actilyse, can improve clinical outcome up to four-and-a-half hours after stroke onset. It included 821 patients (418 treated with alteplase and the rest on placebo) and showed that people treated with the drug beyond the standard three-hour time window had a 34% improvement in the odds of having a favourable outcome versus placebo.

However, researchers also noted that patients on alteplase, a recombinant tissue plasminogen activator, suffered more cases of bleeding in the brain – 27% versus 18% – though it was serious in only about 2%. The death rate was similar in both groups.

Werner Hacke of the Ruprecht-Karls-University of Heidelberg and lead investigator on ECASS 3, insisted that “early treatment remains the cornerstone of acute stroke therapy and it is of paramount importance that patients arriving in stroke units who are eligible for thrombolysis should be treated without delay”. However, the new data shows that stroke can be effectively managed also in patients “who are unable to reach a stroke centre within three hours", he said, “and “a large group of patients currently excluded may benefit in the future from this therapy”.

Whether this data will be enough to result in regulators extending the treatment window for stroke beyond three hours remains to be seen but observers believe the aim needs to be on getting patients to hospital even quicker. In an editorial accompanying the NEJM article, Patrick Lyden, director of the University of California, San Diego Stroke Center, noted that the vast majority of stroke patients get inadequate care and stated that "in fact, the real peril of the data is that some make take an even more leisurely approach to treating acute stroke. Nothing could be more wrong."

He adds that "as we look back on the past decade of thrombolytic therapy for stroke, it is very clear that our focus must remain on the door-to-needle time. Every minute matters during a stroke." Researchers on Dr Hacke’s team echoed that view,saying that “having more time does not mean we should be allowed to take more time".