DAWN Trial Results Presented for Stryker's Trevo Retriever
May 16, 2017—Stryker announced that results from the DAWN trial of the company's Trevo Retriever provided compelling evidence that more patients experiencing ischemic stroke may benefit from endovascular treatment. The trial findings were presented at ESOC 2017, the European Stroke Organization Conference in Prague, the Czech Republic.
The Stryker-sponsored DAWN trial was a randomized, controlled trial designed to evaluate functional outcomes at 90 days in stroke patients treated with mechanical thrombectomy using the Trevo Retriever compared to those receiving 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).
The Trevo Retriever was cleared by the US Food and Drug Administration (FDA) in 2012 for the revascularization of patients experiencing 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 in the United States under an investigational device exemption study approval from the FDA. The Trevo Retriever is currently indicated for treatment up to 8 hours from symptom onset.
According to the company, although previous randomized clinical trials have proven the benefit of stent retrievers within 6 hours of stroke onset, the DAWN trial is the first to evaluate the late-window and wake-up stroke patient population.
Stryker reported that the results from 206 patients enrolled in the DAWN trial demonstrated that treatment with the Trevo Retriever significantly decreased poststroke disability and improved functional independence at 90 days when compared to medical management alone (48.6% vs 13.1%; probability of superiority > .9999), a relative reduction in disability of 73%. The study showed that 1 in 2.8 patients treated with the Trevo Retriever within 24 hours of a stroke is saved from severe disability. Treatment of these selected patients with thrombectomy appears to be as beneficial and imperative as in patients treated in the previously studied < 6-hour time window.
In Stryker's announcement, DAWN Co-Principal Investigator Tudor Jovin, MD, commented, “This is great news for patients who present in the late-time window who may still benefit from this treatment. The number needed to treat was only 2.8, indicating we may see a 270% increase in patients who are able to live an independent lifestyle free of severe disability.” Dr. Jovin is from the University of Pittsburgh Medical Center in Pittsburgh, Pennsylvania.
Co-Principal Investigator Raul Nogueira added, “Despite the longer times to treatment, the reduction in disability in this trial was highly significant—possibly representing the largest treatment effect ever seen in an endovascular stroke trial. These results offer hope for thousands of stroke patients worldwide who arrive at the hospital outside the 6-hour treatment window.” Dr. Nogueira is from Grady Memorial Hospital/Emory University in Atlanta, Georgia.
In March, Stryker announced an early end to patient enrollment in the DAWN clinical trial, which was designed to enroll up to a maximum of 500 patients, with a prespecified interim analysis of data to assess efficacy upon enrollment of the first 200 patients. The independent data safety monitoring board recommended stopping study enrollment based on that interim analysis, which concluded that multiple prespecified stopping criteria were met.