Challenges of Decision Making Regarding Futility in a Randomized Trial

STROKEAHA: April 3, 2014

Background and Purpose—Interventional Management of Stroke (IMS) III is a randomized, parallel arm trial comparing the approach of intravenous tissue plasminogen activator followed by endovascular treatment with intravenous tissue plasminogen activator alone in patients with acute ischemic stroke presenting <3 hours of symptom onset. The trial intended to enroll 900 subjects to ensure adequate statistical power to detect an absolute 10% difference in the percentage of subjects with good outcome, defined as modified Rankin Scale score of 0 to 2 at 3 months. In April 2012, after 656 subjects were randomized, further enrollment was terminated by the National Institute of Neurological Disorders and Stroke based on the prespecified criterion for futility using conditional power <20%. Read More