The Maestro consists of a "pulse generator" surgically implanted under the skin of the chest wall. This delivers high-frequency electrical pulses to leads laid along two trunks of the vagus nerve, which helps control the function of many organs in the abdomen.
The device is intended in use for people with a body mass index (BMI) of at least 40, which is extremely obese. BMI is a measurement of body fat based on height and weight.
EnteroMedics said the Maestro also could be used in people with a BMI of at least 35 who have health problems related to their obesity and have failed to lose weight through other programs. (A BMI of 30 is the threshold for obesity.)
The FDA advisory committee's review included results from a clinical trial that involved more than 200 morbidly (severely) obese people in the United States and Australia. Of those, 157 received a Maestro implant and 76 received a fake implant.
All of the participants then went through a standard weight management program, which consisted primarily of 15-minute counseling sessions. The program did not include more intense interventions such as very low calorie diets, mandatory exercise programs or portion-controlled meals.
Over the course of a year, study participants with the Maestro implant lost just over 24 percent of their excess weight on average, compared with nearly 16 percent of excess weight loss for people who received fake implants.
More than half the participants lost at least one-fifth of their excess weight, and 38 percent lost at least one-quarter of their excess weight, according to the researchers.
EnteroMedics added that people with fake implants regained about 40 percent of the weight they had lost within six months of the trial's end, while the people with the Maestro device appeared to sustain their weight loss.
The device appears to be largely safe, with only about 4 percent of patients suffering a health problem because of the implant, the FDA's report on Maestro said.
However, the Maestro is unsafe during MRI scans and would have to be removed if a person needed an MRI, according to the FDA.