Stryker may have gotten a bit more than they bargained for when it acquired Boston Scientific's neurovascular division in January 2011.
At the 2012 American Association of Neurological Surgeons (AANS) conference, Dr. Brian L. Hoh addressed the controversy that has been plaguing Stryker's (formerly Boston Scientific's) Wingspan stent for the past year. Specifically, Dr. Hoh described the fallout from the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) study, which tested angioplasty plus stenting using Stryker's Gateway-Enterprise system in the treatment of intracranial atherosclerotic disease (ICAD).
Challenges for the device began in April of last year, when the National Institute of Neurological Disorders and Stroke (NINDS) halted enrolment of SAMMPRIS, based on a high complication and death rate using the device. A few months later, in September, results were published in the New England Journal of Medicine showing a similar story: the Gateway-Wingspan system resulted in a 2.5-fold greater risk of stroke or death after 30 days than medical management alone. Following these results, Public Citizen a consumer watchdog group has called for the withdrawal of the Wingspan's 2005 FDA HDE approval.
In a report released on March 23, 2012, the majority of an FDA advisory panel agreed with Public Citizen; the FDA has yet to make a final decision on the Wingspan's fate.
Despite these negative reactions, a number of groups, including the AANS, the Congress of Neurological Surgeons (CNS), and the Journal of Thoracic and Cardiovascular Surgery (JCVS) have argued in favour of keeping the Wingspan's FDA HDE approval. These groups, and many physicians, feel that completely removing the Wingspan from the table is too drastic a reaction, which will leave many high-risk patients with no treatment options. Not all patients benefit from the anti-clotting drugs like Aspirin and Plavix that are used in the medical management of ICAD, a common cause of stroke. Supporters of the Wingspan believe that although stenting may not be a suitable first-line treatment, it is important that physicians have the option and ability to treat this particular subgroup of patients.
Dr. Hoh stated that regardless of the FDA's final decision, the SAMMPRIS trial may have vanquished any possibility for another trial assessing the revascularization of intracranial arteries. He pointed to the example of Micrus Endovascular's Vitesse Intracranial Stent Study for Ischemic Therapy (VISSIT), testing the Pharos Vitesse stent in the treatment of ICAD. In January 2012, the VISSIT trial halted recruitment of patients before reaching its expected enrolment of 250, due to a lack of interest. It appears that the negative public reaction surrounding the Wingspan stent has created a roadblock in the further development of ICAD stenting.
Dr. Hoh urged the neurosurgeons at the AANS annual meeting to take the lead, and attempt to conduct and lead small clinical studies of their own in this field. Otherwise, it seems that the unintended consequence of the SAMMPRIS trial will be the phasing out of a once-promising option for a high-risk subgroup of stroke patients.