For certain obese adult patients, a novel weight loss treatment device that targets the nerve pathway between the brain and the stomach that controls feelings of hunger and fullness has been approved by the U.S. Food and Drug Administration.

The Maestro Rechargeable System is the first FDA-approved obesity device since 2007. The device has been approved to treat patients aged 18 years and older who have not been able to lose weight with a weight loss program, and who have a body mass index (BMI) of 35 to 45, with at least one other obesity-related condition, such as type 2 diabetes.

“Obesity and its related medical conditions are major public health problems,” said William Maisel, MD, MPH, deputy director for science and chief scientist in the FDA’s Center for Devices and Radiological Health in an agency news release.

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“Medical devices can help physicians and patients to develop comprehensive obesity treatment plans.”

The Maestro Rechargeable System consists of a rechargeable electrical pulse generator, wire leads and electrodes implanted surgically into the abdomen. It works by sending intermittent electrical pulses to the trunks in the abdominal vagus nerve, which is involved in regulating stomach emptying and signaling to the brain that the stomach feels empty or full.

Although it is known that the electric stimulation blocks nerve activity between the brain and the stomach, the specific mechanisms for weight loss due to use of the device are unknown. External controllers allow the patient to charge the device and allow health-care professionals to adjust the device’s settings in order to provide optimal therapy with minimal side effects.

The safety and effectiveness of the Maestro Rechargeable System were evaluated in a clinical trial that included 233 patients with a BMI of 35 or greater. The weight loss and adverse events of 157 patients who received the active Maestro device (the experimental group) were compared to 76 patients in the control group who received a Maestro electrical pulse generator that was not activated.

The clinical study did not meet its original endpoint, which was that the experimental group lose at least 10% more excess weight than the control group. However, an FDA Advisory Committee (the Gastroenterology and Urology Devices Panel) found the 18-month data supportive of sustained weight loss, and agreed that the benefits of the device outweighed the risks for use in patients who met the criteria in the device’s proposed indication.

In considering the benefits and risks of the device in its review of the Maestro Rechargeable System, the FDA considered the clinical study and the Panel’s recommendations. Additionally, the Agency looked at an FDA-sponsored survey relating to patient preferences of obesity devices that showed a group of patients would accept risks associated with this surgically implanted device for the amounts of weight loss expected to be provided by the device.

The study found that after 12 months, the experimental group lost 8.5% more of its excess weight than the control group. Patients in the experimental group lost an average of 24.4% of their excess body weight, and patients in the control group lost an average of 15.9% of their excess body weight. 

As part of the approval, the manufacturer must conduct a five year post approval study that will follow at least 100 patients and collect additional safety and effectiveness data including weight loss, adverse events, surgical revisions and explants and changes in obesity-related conditions.

Serious adverse events reported in the clinical study included nausea, pain at the neuroregulator site, vomiting, as well as surgical complications. Other adverse events included pain, heartburn, problems swallowing, belching, mild nausea and chest pain.

The Maestro Rechargeable System is manufactured by EnteroMedics of St. Paul, Minnesota.