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Implantable Nerve Stimulator Approved amid Controversy

Medical Device & Diagnostic Industry Magazine MDDI Article Index   Originally Published MDDI September 2005 NEWSTRENDS  

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

Originally Published MDDI September 2005

NEWSTRENDS

Maria Fontanazza

Controversy surrounding the vagus nerve stimulator has not quieted, especially with its recent FDA approval. Cyberonics is providing educational and safety materials.

After years of debate, FDA signed off on a radical application for a medical device: treating depression. The innovation did not come without significant obstacles for the manufacturer, though—seven years of studies and loads of negative publicity from detractors.

Notable is that the agency reversed itself several times, and the approval process has spawned an investigation by the Senate Finance Committee.
The vagus nerve stimulator, made by Cyberonics Inc. (Houston), is designed for patients suffering from severe depression who haven't experienced an “adequate response” to four or more antidepressant therapies.

However, not everyone agrees that the device is safe and effective. Just days after the device was approved, the Public Citizen Health Research Group released a statement calling FDA's move “one of the most questionable regulatory decisions made by the agency in recent memory.” The group has previously made efforts to prevent approval of the device, including appealing in writing to CDRH director Daniel Schultz.

In 1997, FDA approved the device, marketed under the trade name VNS Therapy System, to treat medically refractory epilepsy. Seven years of studies, which have been called into question, led to the approval and commercialization of its newly indicated use for treatment-resistant depression (TRD). About 4.4 million Americans suffer from the illness.

Cyberonics's VNS Therapy System sends an electrical signal to the vagus nerve in the neck. The system may provide help to severely
depressed patients for whom other therapies have not worked.

Weighing less than 1 oz, the device includes a pulse generator, which is implanted in the left chest. A lead runs under the skin, sending electrical signals from the generator to the vagus nerve in the neck. A magnet can be held over the generator to turn off the stimulator.

According to Peter Lurie, MD, deputy director of Public Citizen, the design of the studies didn't produce results showing that the device works. “The approval process was extremely unusual. FDA reversed its advisory committee and then reversed itself. That is not the way things usually happen.”

Cyberonics posted the physician and patient manuals on its Web site, and FDA posted the Summary of Safety and Effectiveness on the agency's Web site. “That's the best response that one can give to ill-informed commentary that may or may not have a different agenda than improving the lives of people touched by TRD,” says Robert Cummins, chairman and CEO of Cyberonics. “FDA and Cyberonics provided all the facts, data, and scientific evidence that provided the basis for the approval.”

Upon viewing this summary, Lurie responded, “The point of this is not supposed to get more bad data—it's to go out and get some good data.” He added that Congress is investigating the approval process of the device.

“It appears, judging from [an article in] the Wall Street Journal, that the reversal within FDA took place at a very high level, suggesting that the lower level of scientists within the government was overruled,” says Lurie. “It's good that the finance committee will look into it to see whether or not political considerations played any part in this [process] approval.”

Copyright ©2005 Medical Device & Diagnostic Industry

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