Abbott Laboratories (NYSE:ABT) goes before a Food & Drug Administration panel Jan. 26, seeking to expand the indication for its RX Acculink carotid artery stent.
Originally granted pre-market approval in August 2004 for high-risk patients, the RX Acculink is designed to relieve obstructions in the carotid artery, the main blood feed to the brain. Rather than surgically opening the artery to remove the obstructing plaque, the stent is inserted via catheter to prop open the blood vessel. The company is seeking to have the device’s indication include standard-risk patients.
The move for an expanded indication follows the release of data from a large study of the device last summer. The 2,500-patient Crest study, comparing carotid stenting with the RX Acculink device and carotid endarterectomy (surgical removal of arterial plaque) showed that stenting resulted in an adverse event rate of 7.2 percent, compared with 6.8 percent for CEA procedures. That bodes well for Abbott, at least according to an FDA executive summary (PDF).
“[The expanded] proposed indications are supported by a primary analysis of the CREST trial data and by multiple important secondary and tertiary analyses,” according to the summary. “The frequency of adverse events to the patients and problems with the device as reported to the sponsor is relatively low. The sponsor reports that the RX Acculink has not been withdrawn from marketing in any country for any reason.”
Despite the seemingly positive feedback from the FDA, the Circulatory System Devices Panel will also consider whether the Crest trial had a major flaw, as some critics suggest. When the study was designed, it was believed that heart attacks suffered just before, during or just after procedures led to a significantly higher risk of death at six months. But that has turned out not to be the case, meaning that one of the trials most significant endpoints may not be valid, Dr. Anthony Comerota of the University of Michigan told the heartwire website.
“An asymptomatic myocardial infarction, a troponin leak, is not associated with an increased mortality risk and is not associated prognostically with an increased mortality risk over the next four or five years. So now we have a major trial equating an elevation in cardiac enzymes with stroke or death,” Comerota said. “That clearly is inappropriate, but when enthusiasts of carotid angioplasty and stenting want to present their side of the story, they’ll say there is no difference because of the higher myocardial infarction rate [with surgery]. Myocardial infarction didn’t alter the quality of life of patients down the road, whereas stroke, even minor stroke, altered the quality of life significantly.”
The FDA advisory panel will hash out the pros and cons in an all-day meeting today. But even if the committee gives a green light to the expanded indication (and if the FDA goes along with the recommendation), Abbott still faces a major hurdle: Convincing the Centers for Medicare and Medicaid Services to approve reimbursement for standard-risk patients.