DAWN Trial Results Published for Stryker's Trevo Retriever
November 13, 2017—Stryker announced that the results of the DAWN trial were published by Raul G. Nogueira, MD, et al online ahead of print in The New England Journal of Medicine. Dr. Nogueira and Tudor Jovin, MD, served as Coprincipal Investigators of the DAWN trial. In May, the company announced the presentation of the trial findings, which were presented at ESOC 2017, the European Stroke Organization Conference in Prague, the Czech Republic.
The company-sponsored DAWN trial was designed to evaluate functional outcomes at 90 days in stroke patients treated with mechanical thrombectomy using Stryker's Trevo retriever compared with those undergoing medical therapy alone. Patients were screened for inclusion in the trial if they had a stroke that started within 6 to 24 hours or a stroke with an unknown time of onset—a significantly longer treatment window than the currently cleared thrombectomy indication.
According to the company, the trial provides compelling evidence for treating late-window and wake-up stroke patients with mechanical thrombectomy. Currently, fewer than one in 10 patients with an ischemic stroke undergoes thrombectomy, partly because of a lack of scientific evidence supporting treatment beyond 6 hours.
In the company's announcement, Dr. Jovin commented, "By quadrupling the size of the therapeutic time window, the consequence of DAWN is that many more patients with large vessel occlusion stroke have the potential to be treated with mechanical thrombectomy. DAWN validates the physiological, rather than a time-based approach to patient selection for endovascular therapy."
Dr. Nogueira added, "Time alone should no longer be a disqualifier for thrombectomy but rather only a source of urgency. We hope this new treatment paradigm will benefit a large proportion of patients who were previously deemed untreatable."
Stryker noted in its announcement that the results of the DAWN trial offer the first level 1 evidence of significantly reduced disability in patients who present in the late time window. However, the company advised that best outcomes are achieved when patients are treated as quickly as possible, requiring increased patient awareness, emergency medical services outreach, and hospital infrastructure to be in place.
The Trevo retriever was originally cleared by the US Food and Drug Administration (FDA) in 2012 for the revascularization of patients experiencing an ischemic stroke. The device's indication within the DAWN trial—for use in patients treated 6 to 24 hours after last seen well—is currently approved for investigational use only under an FDA investigational device exemption.
The DAWN data were briefly summarized in an announcement from UPMC, the University of Pittsburgh Medical Center in Pittsburgh Pennsylvania, where Dr. Jovin is Director of UPMC's Stroke Institute and the Center for Endovascular Therapy and Professor of Neurology and Neurosurgery at the University of Pittsburgh. The results showed clinical benefit with nearly half the patients (48.6%) who underwent endovascular therapy having a good outcome at 90 days after treatment—defined as the patient being independent in daily living activities—while only 13.1% of patients in the group that received clot-busting drugs alone showed benefit. There was no difference in mortality between the two groups.
The UPMC press release noted that the DAWN investigators planned to enroll a maximum of 500 patients over the course of the study period. However, a preplanned intermediate review of the treatment effectiveness when 200 patients were enrolled led the independent data safety monitoring board overseeing the study to recommend early termination of the trial based on predefined criteria demonstrating that clot removal provided significant clinical benefit in the selected patients. The multicenter, international DAWN trial was conducted in the United States, Spain, France, Australia, and Canada, stated UPMC.