Opinions Vary on New Vagal Blocking Device for Weight Loss

Miriam E Tucker

March 02, 2015

The role of the recently approved vagal blocking device for the treatment of obesity in the United States is yet to be determined, judging by the varying opinions of five experts.

Approved by the Food and Drug Administration (FDA) in January, the VBLOC vagal blocking therapy is delivered via the Maestro System (EnteroMedics) and consists of a rechargeable neuroregulator device implanted into the lateral chest wall with flexible leads placed laparoscopically around the vagus nerve, intermittently blocking signals and thereby reducing hunger and increasing feelings of satiety.

In the pivotal randomized clinical trial of 233 patients with a body mass index (BMI) of 35 kg/m2 or greater, the group with the active device (as opposed to implanted but not activated) lost 8.5% more body weight than did the controls after 12 months, with about half (52.5%) of the active-device group losing at least 20% of their excess weight and 38% losing at least 25%.

The VBLOC is indicated for the treatment of obese adults who have a BMI of 40 to 45 kg/m2 or of 35 kg/m2 or greater with comorbid conditions such as hypertension or dyslipidemia and who have tried and failed at least one supervised weight-management program within the past 5 years.

Some patient stories with this new device are featured in a video presentation that forms part of WebMD's Future of Health series with Robin Roberts, which launched today. This also includes a round-up on all novel obesity treatments, aimed at a consumer audience.

Surgery Time and Training, Cost of Device

The surgical implantation takes about 60 to 90 minutes and is usually done on an outpatient basis. Enteromedics is currently undertaking a "controlled commercial rollout" by training surgeons on the implantation procedure at bariatric centers of excellence around the country.

Between 20 and 25 centers in the United States are expected to have qualified surgeons by the end of the year, company chief commercial officer Brad Hancock said in a February 18 investor call.

Regarding the cost of the device, a company spokesperson told Medscape Medical News that this is "between [that of] a gastric band…and a gastric-bypass surgical procedure," adding that the company is currently working on securing reimbursement from private and public payers.

The United States is not the first market for this device — it was technically approved in Australia 3 years ago, when it gained therapeutic goods administration (TGA) clearance, and it has also received a CE Mark in Europe.

But the company appears to have held back in these markets, until it was clear it would gain US approval for the device.

"In Australia, we are focused on reimbursement for the implantation procedure and our device in parallel. Reimbursement of the hospital and surgeon is reliant upon obtaining an item number code, while listing on the prosthesis list secures reimbursement for our device," the spokesperson said.

"Now that our pathway in the US is clear, we expect to accelerate our activities in other territories," she added.

Safer, but Still Surgery

One physician who has acted as a consultant to Enteromedics and who testified on behalf of the device at the FDA device advisory committee hearing in which VBLOC was reviewed says it's safer than bariatric surgery.

"Even though it's a surgical procedure, it is extremely safe. You don't get the complications that you do when you do anatomy-altering surgeries," Caroline M Apovian, MD, from the Nutrition and Weight Management Center at Boston Medical Center, Massachusetts, said in response to a question during a web briefing in January announcing Endocrine Society guidelines for pharmacologic obesity treatment.

Moreover, "It's reversible. You can just take it out, and it doesn't permanently alter anatomy." On the other hand, "The patient can have the device in for years, promoting satiety on a daily basis. They eat less and keep the weight off."

And in her experience, patients prefer it. "With this device, you don't have to alter the way you eat. You can eat your favorite foods, you're just going to eat less. With bariatric surgery, if you eat a lot of high-carb foods you can get dumping syndrome. People like the idea of this device much more than surgery, even though surgery gives you the most weight loss," Dr Apovian said.

Other obesity experts aren't so sure. Obesity Society secretary-treasurer Martin Binks, PhD, from Texas Tech University, Lubbock, told Medscape Medical News, "It's a less intensive surgical procedure, but there's no minor surgery in my opinion. The reality is they're undergoing a surgical procedure."

Dr Binks, who testified at the FDA VBLOC hearing on behalf of the Obesity Society that more obesity treatments are needed, but not specifically in support of this device, added, "I think it might provide an option for some people who don't like the other options or who haven't had success with the other options."

But, he added, "By definition we have to have already tried less intensive methods….We do the least intensive intervention to obtain the effect first in all medicine. I look at it that way."

"This Is Complicated Stuff: You've Got to Have Respect for the Vagus"

For Aaron M Cypess, MD, PhD, section head of the Translational Physiology Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes, Digestive and Kidney Diseases, Bethesda, Maryland, the VBLOC's mechanism of action is a bit of an enigma, since stimulation of the vagal nerve has also been linked to increased energy expenditure via activation of brown fat, a topic that is part of his research focus.

He likened the contradictory mechanisms to that of parathyroid hormone, which causes bone to release calcium into the blood but also can build bone when taken pharmacologically (teriparatide).

"So it's not surprising that you could have efficacy from blocking the vagal nerve one way and stimulating it another way. But what it means is this is complicated stuff."

He added, "It's always nice to have more approved interventions available to the clinician, so that's good. But before I would be using something like this, I would want to know a lot more about who benefits the most. Given research suggesting that stimulation of the vagal nerve may also have benefit, how do those two play with each other?"

Dr Cypess also noted that the vagus is a major nerve with branches throughout the body, including the neck, gastrointestinal tract, and heart, that plays a major role in both the autonomic and sympathetic nervous systems.

"There's always the possibility of some harm when you suppress such a centrally important nerve in the body. It's not just any nerve. You've got to have respect for the vagus."

And with regard to the VBLOC, "As a [National Institutes of Health] NIH person and a clinician, I want to see more research."

Is VBLOC Worth the Price?

Meanwhile Craig Primack, MD, of the Scottsdale Weight Loss Center, Arizona, and a spokesperson for the obesity drug Qsymia (phentermine and topiramate extended-release, Vivus) as well as a consultant for other weight-loss drug manufacturers, questioned whether the VBLOC is worth its cost, noting that the amount of weight lost is far less than with bariatric surgery, for about the same price.

"If you look at the amount of money we're spending on that particular device…I think you're getting more bang for your buck with one of the surgical procedures. The efficacy [of VBLOC] is much less."

Arya M Sharma, MD, an obesity expert from University of Alberta, Edmonton, where the VBLOC has not yet been approved, told Medscape Medical News that although the device was shown to be effective for some people, "Is this a device you're going to recommend to every patient? Probably not. Who is it best suited for? I don't know."

Added Dr Sharma, "If you can get away with simply taking a tablet every day, you're way better off than any surgical device you can possibly imagine."

However, he said he might consider the VBLOC "for a high-risk patient, or maybe [base the decision on] individual preferences. [Enteromedics] has evidence that it works, which is good. Now the question is who does it work best for, and how does it compare with other treatments? We don't know."

Dr Apovian serves on advisory boards for Amylin, Merck, Johnson & Johnson, Arena, Nutrisystem, Zafgen, Sanofi, Orexigen, and Enteromedics. She has received research funding from Lilly, Amylin, Aspire Bariatrics, GI Dynamics, Pfizer, Sanofi, Orexigen, MetaProteomics, and the Dr Robert C and Veronica Atkins Foundation. Dr Primack is a speaker for Vivus, Novo Nordisk, Eisai, and Takeda. Dr Sharma serves as an advisor/consultant for Novo Nordisk, Takeda, Ethicon, and Zafgen. Dr Binks conducts educational programs for Orexigen Therapeutics and Novo Nordisk. Dr Cypess has no relevant financial relationships.


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