Featured Stories

Trial puts treatment for obesity to the test

At OHSU, neuroblocking device will tell people’s brains they’re full

Sign-ups begin this week at Portland’s Oregon Health and Science University for a clinical trial on a radical new treatment for obesity. The new technology involves implanting in participants a flat, silver dollar-size device that will send signals to their brain reducing their appetites and increasing their sense of being full — no matter how much they’ve eaten. The device uses technology called neuroblocking. Implanted beneath the skin next to the stomach, and powered by an external battery pack worn on a belt, it sends signals up the body’s vagus nerve to the brain. The vagus nerve provides communication between the brain and the digestive system. According to Bruce Wolfe, the professor of surgery at OHSU’s school of medicine who is conducting the trial locally, the foundation of the experimental therapy came decades ago, when physicians treating patients for ulcers observed that cutting the vagus nerve reduced patients’ appetites. Neuromodulation technology until now has been used to treat epilepsy, pain and depression, Wolfe said. But its use for appetite control is new. So far, the technique has been tested in only a handful of patients, all outside the United States. OHSU is one of 13 sites across the country where clinical trials for what is called the Empower Study will be taking place. Wolfe sees great potential for the new therapy, if it proves successful. “The market could be almost unlimited,” he said. Wolfe said people who enroll in the five-year OHSU trial, which is free of charge, might experience considerable weight loss if the technology’s preliminary data proves accurate. EnteroMedics, manufacturer of the device, claims that patients might lose 20 percent of their excess weight each year. But there is a catch. Because the trial will follow research protocols that call for a “control” group, in the first year, one out of three patients won’t actually be getting the neuroblocking therapy. The device will have been implanted, they will wear the special belts 15 hours a day, but they will be part of the placebo group against which the other participants’ weight loss will be measured. After the first year of the study, if data shows participants with operable devices are losing more weight, all participants will have their neuroblockers turned on, according to an EnteroMedics spokeswoman. Keeping it off is the trick Participants won’t necessarily be able to rid themselves of the devices once they’ve lost their excess weight. William Raum, an endocrinologist at the Obesity Institute at Portland’s Legacy Good Samaritan Hospital and Medical Center, said he is on the verge of conducting a trial for a similar competing device. He says that history has taught physicians that medical interventions that help people lose weight don’t necessarily help people keep it off. Raum said that when lap band surgery — which places a band around the stomach to reduce its capacity — was introduced for weight loss, it was expected that surgeons would be able to remove the bands after six months or a year. But physicians discovered that patients quickly gained back the weight they had lost, Raum said. Neuromodulation devices, Raum said, are being devised as lifelong treatments. Raum said the expectation is that they may not be as effective in terms of weight loss as current weight loss surgery — either lap band or gastric bypass surgery — but the surgery itself for implanting the devices is much less invasive. According to Wolfe, that could make the potential market for neurotransmission treatment of obesity enormous. EnteroMedics estimates there are 13 million potential candidates for the device in the United States alone. Less invasive methods appeal Nationally, one in four people is considered obese in this country, which is defined as a body mass index (a ratio of weight and height) of 30 or greater. In Oregon, six of 10 adults are either obese or clinically overweight. Even with those numbers, Wolfe said, the use of weight loss surgery is low. “That’s one of the teasers about obesity and bariatric (weight loss) surgery in general,” Wolfe said. “Less than 2 percent of the population who could have bariatric surgery is getting it.” Wolfe theorized that greater numbers of obese people don’t turn to surgery because they fear complications, such as infection, might result. Those complications would be much less likely with the less invasive surgery needed to implant the neuroblocking devices, Wolfe said. “It’s a lesser procedure, and it most likely will be safer,” Wolfe said. “If it works as well (as conventional weight loss surgery), the market could be huge.” With appetites neurologically suppressed and a constant feeling of being full, users of neuroblocking technology might be expected to face nutritional deficits. But Wolfe said that previous technologies for obesity show that to be an unnecessary concern. “People eat for reasons other than appetite,” Wolfe said. “It’s a very complicated human behavior.” This email address is being protected from spambots. You need JavaScript enabled to view it.