Covidien Trial Demonstrates Benefits of Mechanical Thrombectomy

Mansfield, Mass.-based medical device company Covidien plc is reporting positive results from its two-year Solitaire FR Thrombectomy for Acute Revascularization (STAR) study, which evaluated the overall safety and efficacy of the Solitaire FR revascularization device in acute ischemic stroke treatment.

Recently, the National Institute of Neurological Disorders and Stroke (NINDS) indefinitely put on hold its IMS III study, which examined whether a combined intravenous (IV) and intra-arterial (IA) approach to recanalization is superior to standard IV rt-PA (recombinant tissue plasminogen activator, a protein used to break down blood clots—in this case Activase) alone when initiated within three hours of acute ischemic stroke onset. The Data and Safety Management Board (DSMB) recommended the trial be stopped, though it cited no “serious safety concerns,” and noted that subject follow-up should continue. A NINDS statement cited “futility” as the cause for ending the trial, which ostensibly meant that no useful results were forthcoming. This study, like Covidien’s, looked at mechanical methods of thrombectomy.

“In the wake of the failed IMS III Study, a NINDS-funded randomized controlled trial, there will be some physicians who will question the benefit of mechanical thrombectomy,” said Vitor Mendes Pereira, M.D., MSc, principal STAR study investigator and head of interventional neuroradiology at University Hospital of Geneva, Switzerland. “The results of the STAR prospective, multi-center clinical study demonstrate that mechanical thrombectomy is both safe and effective for the treatment of acute ischemic stroke when treating the right patients in comprehensive stroke centers with the Solitaire FR device.”

According to a 2011 study in The New England Journal of Medicine, acute ischemic stroke (AIS) is the most prevalent form of stroke, accounting for up to 87 percent of all stroke-related cases worldwide. In AIS, the patient suffers from an acute blockage of blood flow (ischemia) to the brain, which, if not treated in a timely manner, leads to permanent neurological damage and possibly death. In 2008, the direct and indirect cost of stroke in United States was $39 billion. AIS affects approximately 800,000 patients annually in the United States, and this number is expected to increase 22 percent in the next 20 years. It is estimated that, on average, 1.9 million neurons are lost every minute an AIS goes untreated, according to J.L. Saver’s 2006 article, “Time Is Brain—Quantified” (published in the American Heart Association’s journal Stroke). AIS leads to regions of brain tissue that have no blood supply and are at risk for permanent tissue damage.

The STAR trial was a prospective, multi-center, single arm clinical study that started with 202 patients at 14 centers across Europe, Australia and Canada. It began in May 2010, with the last patient completing participation in October 2012. In the study, patients diagnosed with AIS (as confirmed by radiographic assessment) were treated with the Solitaire FR device in order to reopen, or recanalize, the blocked blood vessels. The results of the STAR study indicated that 84.2 percent (160 of 190) of patients with complete angiographic data sets and 79.2 percent (160 of 202) of patients with missing angiographic data, as determined by an independent laboratory, achieved the highest degree of recanalization. Long-term follow-up was obtained at 90 days to evaluate neurological health. Using the Modified Rankin Score (mRS), 57.9 percent achieved a score of 2 or less, indicating functional independence, with little to no disability. An independent clinical events committee reported a 6.9 percent (14 of 202) mortality rate and a 1.5 percent (3 of 202) symptomatic intracranial hemorrhage rate.

“The STAR study adds to the evidence supporting the use of the Solitaire FR device as a tool for revascularization in acute ischemic stroke care,” said Mark A. Turco, M.D., chief medical officer of vascular therapies at Covidien. “Given the medical and economic burden of AIS to patients and healthcare systems, there is an urgent need to develop innovative solutions for the timely, safe and effective treatment of acute ischemic stroke. The Solitaire FR device represents new hope in addressing this widespread public health issue.”

Analysts at Zacks Equity Research said Covidien is “well-positioned to expand in this high-growth stroke care market.”

The Solitaire FR revascularization device restores blood flow by removing blood clots from a large intracranial vessel in patients experiencing ischemic stroke within eight hours of symptom onset. It is designed for mechanical blood clot removal in the neurovasculature, including the internal carotid artery, M1 and M2 segments of the middle cerebral artery, and the basilar and vertebral arteries. The Solitaire FR received CE mark approval in 2009 and U.S. Food and Drug Administration 510(k) clearance in 2012.