Blocking the Hunger Nerve

Entrepreneurs at EnteroMedics developing a new treatment for obesity by blocking the “hunger nerve” (the vagus) have had a bumpy ride along the way. This week, the results of their pivotal clinical trial were published in the Journal of the American Medical Association (JAMA). Alongside this publication was a commentary on the state of the evidence base for bariatric surgery, which offered up a somewhat unhelpful perspective.

The results of the study were mixed, consistent with the mixed review an FDA advisory committee gave the Maestro VBLOC medical device in June at a public hearing. The committee voted that EnteroMedics had proven that the device is safe for clinical use.and that it appears to offer benefits that outweigh its risks. But they also said that the efficacy data was less than definitive.

In the JAMA publication, investigators report 24% excess weight loss with 12 months of active treatment, compared to 16% for subjects who were implanted with a sham device. The difference in the blinded, randomized, controlled study was statistically significant (p=0.002), but it fell short of the pre-specified goal of more than a ten percentage point difference. People responded to the sham device better than expected. Of course, they received behavioral therapy, along with the sham device.

In the commentary, David Arterburn and David Fisher say that “although vagal nerve blockade therapy is an innovative approach, it does not appear to be a sustained, effective treatment for severe obesity.”

We would disagree. It’s clear from these data that this device is relatively safe. And it’s clear that it doesn’t offer dramatic across-the-board efficacy for all patients. But it also appears to be effective for some patients who need another option. For responders in the clinical trial, VBLOC therapy meaningfully improved their lives.

An open question remains. FDA approval is still pending. Will EnteroMedics successfully complete the work they have begun to define a meaningful clinical role for this innovative technology?

Time will tell.

Click here to read the study and here to read the commentary. Click here to read more from MedicalXpress.

Neurons, photograph © Birth into Being / flickr

Subscribe by email to follow the accumulating evidence and observations that shape our view of health, obesity, and policy.