Saturday, May 21, 2005

Questionable Deliberations on the Vagus Nerve Stimulator to Treat Severe Depression

The NY Times reports on the curious deliberations by a US Food and Drug Administration (FDA) expert advisory panel on the approval of an implanted vagus nerve stimulator as a treatment for severe depression. The committee was informed about the results of a randomized controlled trial which, as far as I can tell after several PubMed searches, has not yet been published.
The Times reports the trial showed that 17/111 patients who had the stimulator implanted and turned on had improvements in "standard measures of disease severity," while 11/110 who had it implanted, but not turned on also improved. This small increase in the likelihood of improvement was not statistically significant, i.e., could have been due to chance alone, rather than be an effect of the device. Furthermore, the absolute benefit increase implied by these data is at most 4.3%. That is, were 100 people to get the device, this data implies only 4 of them might improve because of it, while the rest would either not improve, or would have improved even without it.
Nonetheless, after hearing some emotional testimonials by patients who claimed that the device helped them, the advisory committee voted to make the device "approvable." The panel's chair, Dr. Kyra Becker, said "the feeling was that anything that gives these people hope is potentially worthwhile." However, one dissenter, Dr. Richard Malone, was bewildered by the panel's decision, "I walked out of there thinking I was nuts. It was stunning, but then I find much of life stunning."
The FDA does not have as rigorous standards to approve devices as those to approve drugs. However, when a device costs $15,000, is invasive, cannot be easily removed, and at best seems as if it may help only a small minority of patients, as is the case for the vagus nerve stimulator, the wisdom of these relatively lax standards comes into question.
Another question is why a scientific advisory committee, staffed ostensibly by medical experts, seemed more attentive to testimonials than to the results of a randomized controlled trial. Perhaps we will get some answers from an investigation by the Senate Finance Committee, which apparently is ongoing.


Anonymous said...

I have done a lot of reading about the vagus nerve stimulator and
know it is for me. can you help me get the VNS I am willing to do
whatever it takes to get this.
Very Sincerely Jeff Forester. Please reply.

Roy M. Poses MD said...

No, the point was that there is no good evidence that the vagus nerve stimulator does any good.

Anonymous said...

My sister had a Vns device put in to control her siezures and it almost killed her. It is bad enough now that she is permanetly disabled because of it. This is a woman who graduated from college, went on to become a registered nurse, was raising her daughter by herself and in the middle of purchasing her first home and now because of this device she will be forced to live on Social Security Disabillity for the rest of her life. This is so incredibly sad and tragic. None of this had to happen. And then when I discover the transcript to a conference call that took place on Feb. 19, 2009 between Daniel Moore, Anthony Petrone and Gregory H. Browne discussing on whether or not they heard back from the FDA on their request to change the structure of the dosing study from 460 patients to 330 I am absolutely infuriated. This was one of the "Conditions of Approval" given to them in 2005 and here it is 2009 and it is very clear they not only are not going to meet this condition but now they want to change it? Where exactly is the FDA's backbone? Is this why so many people every year die or are seriously injured from the devices and drugs that the FDA is letting slip by because they can't even honor their own conditions? If that is the case, then why are we even wasting tax payers money on paying their salaries? What good are they?