Despite the near unanimous vote on the risk-benefit question, the votes on safety and effectiveness were mixed. The panel voted 8-1 that there was reasonable assurance the device was safe for the indicated use, but voted 5-4 that there was not reasonable assurance that it was effective for that indication. Those voting in favor of risk-benefit were swayed by the evidence it was effective in some patients and was reasonably safe.
One of the panelists voting yes on the risk-benefit question, Dr. Karen Woods, a gastroenterologist at the Methodist Hospital, Houston, said that the data provided by the company indicated the device was beneficial and referred to the need for less-invasive devices to treat obesity. "I would say they have shown they have effectiveness, just not particularly meeting the exact criteria they created for the study," she noted. "I feel we’re filling in a little bit of an area of unmet need ... and it will either go on to be effective or it won’t be, but I don’t think we’re going to do a lot of harm."
©EnteroMedics
The device reduces sensations of hunger by delivering electrical blocking signals to the anterior and posterior trunks of the intra-abdominal vagus nerve.
The two panelists voting no on the risk-benefit question said they voted no because the effectiveness endpoints were not met, despite evidence of superior weight loss in the treated group. "It’s close, it’s approaching clinical and statistical significance, but it doesn’t reach it," said Dr. Gary Falk, a gastroenterologist and professor of medicine at the University of Pennsylvania, Philadelphia.
Concerns raised by the panelists included the lack of racial diversity and the low number of men enrolled in the study, which made it unclear whether the results could be applied to the general population of obese patients; possible detrimental effects on the vagus nerve after leads are explanted, and the lack of long-term follow-up data for a device that could remain in place for a lifetime. Another concern is that patients with the device cannot undergo magnetic resonance imaging.
The company expects an FDA decision on approval later this year, according to a statement released by EnteroMedics after the panel meeting. If the device is approved, the company plans postmarketing studies, a 5-year follow-up study of patients in the ReCharge trial and a registry study of 500 patients in the United States.
The FDA usually follows the recommendations of its advisory panels. Panel members have been cleared of potential conflicts, but occasionally, a panelist is given a waiver. At this meeting, a waiver was granted Dr. Woods, who holds stock in a company with a competing product, according to the FDA briefing documents.