The Class-I study involved the treatment of 1,200 patients suffering major stroke over three years in the USA and Canada. Preliminary results of the study will be presented at the World Stroke Congress later this month.

Although Zendra was not a high priority project for AstraZeneca, the Class-I study represented important research into stroke, a difficult area of treatment with high unmet medical need.

Dr.Patrick Lyden, Co-ordinating Investigator of the Class-I trial and Director of the University of California/ Veterans' Affairs Stroke Center at San Diego, said: "While these results are disappointing, we continue to view stroke as a treatable disease and we will continue our search for effective treatments."