US approves first-of-kind device to treat obesity

A first-of-its-kind implant to treat obesity that curbs the appetite by electrically stimulating stomach nerves has been approved in the US.
The Maestro Rechargeable System is approved to treat patients aged 18 and older who have not been able to lose weight with a weight loss programme, and who have a body mass index of 35 to 45 with at least one other obesity-related condition, such as type 2 diabetes.
The US Food and Drug Administration (FDA) approved the implant for certain obese adults, the first weight loss treatment device that targets the nerve pathway between the brain and the stomach that controls feelings of hunger and fullness.

BMI, which measures body fat based on an individual's weight and height, is used to define the obesity categories.
According to the Centres for Disease Control and Prevention, more than one-third of all US adults are obese, and people with obesity are at increased risk of heart disease, stroke, type 2 diabetes and certain kinds of cancer.
"Medical devices can help physicians and patients to develop comprehensive obesity treatment plans," said William Maisel, deputy director for science and chief scientist in the FDA's Centre for Devices and Radiological Health.

The 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 signalling 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 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 study found that after 12 months, the experimental group lost 8.5 per cent more of its excess weight than the control group, FDA said.
About half (52.5 per cent) of the patients in the experimental group lost at least 20 per cent of their excess weight, and 38.3 per cent of patients in the experimental group lost at least 25 per cent of their excess weight.