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.
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