FDA spokeswoman Karen Riley said the agency is engaged in an ongoing effort to improve overall medical device safety monitoring. "We have an initiative underway to strengthen post-market monitoring," she said.
But Brownlee believes the story of the VNS device to be just one example of the FDA's failure to monitor the safety of medical devices before and after they are out in the marketplace. For example, she pointed out that less than one-third of devices approved under FDA's pre-market approval process had ever been evaluated in a randomized trial.
And she said that it was physicians, not the FDA, who spotted serious problems with certain implanted defibrillators, for example. "It was physicians keeping their own database that alerted the company to the problem," Brownlee said.
Moreover, she believes the agency is not capable of detecting potentially unsafe devices through its own harms database. Brownlee cited a finding that many post-approval studies are either not done, or conducted so poorly "as to be meaningless."
According to the BMJ, the FDA referred Brownlee and Lenzer to five post-approval studies that they said established the device's safety. However, Brownlee said these studies do not prove the device was not the cause of deaths, since none contained mortality data.
Brownlee also said that when the device was approved for depression it was over the objection of FDA's own panel of scientists. And, according to Brownlee, the company has suggested that VNS may be useful for a wide range of other ailments, including obesity, stroke and traumatic brain injury, and has patented the device for these potential therapies.
According to Brownlee, the FDA will only improve when it gets more staff, better funding, more authority and more outside experts to objectively evaluate device safety.
The new findings come on the heels o
All rights reserved