FDA Panel Recommends Device for Depression
Experts Want Device Restricted to Most Severely Ill Patients
Some panelists asked the company to go back and perform a randomized trial of patients with VNS against those receiving a sham surgery in which no stimulation is delivered.
"We can guess all we want, we can speculate. But I don't find this at the acceptable level of a randomized, controlled trial," says Richard P. Malone, MD, a professor of psychiatry and epidemiology at Brigham and Women's Hospital in Boston and a member of the panel.
The committee asked the FDA to require labeling that confines VNS to patients who have gotten no benefit out of at least four existing medical depression treatments. They also want the FDA to require that psychiatrists receive special training before using the device to treat patients.
Safety in Question
Up to two-thirds of patients using VNS for depression or epilepsy experience alterations in their voice because of the electrical pulses to the vagus nerve. Many patients also experience mild side effects including persistent cough. Patients can deactivate the device with a magnet if they become uncomfortable or want to alleviate the voice alterations.
About 1% of patients using the device for epilepsy have to have it removed due to infections, according to the company.
But the experts are more uneasy about suggestions that the implants may carry risks for some patients. Thirty-one patients in one study of 235 subjects had episodes of deepening depression, and many had two or more episodes of worsening depression, according to the company.
Twenty-five patients using VNS also attempted suicide in several company studies. The experts acknowledge that suicide is a common risk in severely depressed patients but say they are still worried about the product's safety.
"There's enough to make us concerned that there might be something to participation in suicide with this device," says Michael J. Schlosser, MD, an FDA medical officer.
Some members of the advisory panel urged the company to perform more randomized studies comparing patients using VNS to those getting traditional antidepressant treatment.
Others cautioned that requiring more studies could deprive very sick patients for whom other treatments do not work.
"I'm concerned about the potential burden to patients who might not be able to receive a viable treatment for this very severe illness," says Fochtmann, a psychiatrist from the State University of New York in Stony Brook.
A. John Rush, MD, a psychiatrist at the University of Texas Southwestern Medical Center in Dallas and a Cyberonics consultant, says approving VNS is appropriate even though the company did not submit a randomized, controlled study as is customary with most FDA approvals.
"If we help one in four or one in five ... that is a home run in a patient population where we just don't see [improvement] in the long run," he says.