High-frequency, low-energy electrical impulses or low intensity signals – either way, it appears that the EnteroMedics' (St. Paul, Minnesota) neuroblocking technology to treat obesity seems to work. Preliminary results albeit unexpected – from the EMPOWER study were reported last week revealing that the control arm of the study reaped almost as much benefit from the therapy as the treatment arm.
The Maestro System, also known as VBLOC Therapy, was implanted in all study participants. It was turned on fully in the treatment arm and at a very low signal with the control arm so that patients and investigators wouldn't know the difference. To everyone's surprise, those very low signals had a significant result.
"The control arm of the trial, which was intended to be inactive, apparently provided a low intensity blocking signal that introduced VBLOC Therapy," Mark Knudson, PhD, president/CEO, said during a conference call. "The EMPOWER study didn't meet the primary endpoints because there was no difference at 12 months between treatment and control. The level of weight loss in the control arm was unusually high."
After 12 months, all patients had lost an average of 16.6% of their body mass index (BMI). Those in the treatment arm who used the device an average of 10.9 hours per day lost 23.1% and a 22.6% loss was reported in the control arm.
"This certainly wasn't anticipated," EnteroMedics' investor relations representative, David Pitts, Argot Partners (New York), told Medical Device Daily.
In early October, Knudson reported the preliminary results and noted disappointment. But after closer analysis of the data, the company now realizes that the device seemed to work even in the control group. But before that happened, EnteroMedics reduced its workforce and operating costs in order to preserve capital and streamline its operations following that initial report of those top-line results. That reduction lowered the number of employees by 40%, to a total of 33. It was expected to result in $3.2 million in reduced operating expenses in 2010.
Pitts said those employees who were laid off will not be invited back despite the positive data because the company needs the funding to push forward.
Katherine Tweden, PhD, EnteroMedics' VP, research and clinical, further explained what happened in the study during the conference call.
"Before we began EMPOWER, the existing literature led us to believe that signal blocking was related directly to the amount of energy delivered to the nerve," she said. "We tested a variety of signal intensities. Our preclinical work led us to believe that low-intensity signals had only a brief and low effect. But the cumulative effect of the control arm signal may have been sufficient."
EnteroMedics' approach to weight loss therapy could change the obesity treatment landscape if it gets FDA approval. Existing approaches, mainly gastric bypass or banding, alter the anatomy and can result in significant complications for patients.
VBLOC Therapy neuroregulates nerve and organ function. The vagal nerves regulate stomach and pancreas activity and it's thought that these nerves also affect satiety and hunger. Implanted leads attached to a device worn around the waist deliver electrical signals to these nerves to reduce hunger.
"The therapy doesn't require the anatomy to be altered or to restrict the stomach; no serious adverse events have been reported from over 400 patient hours of safety data," Knudson said.
As an added bonus, the study found that participants who had been previously diagnosed with hypertension experienced a decrease in blood pressure. A follow-up study is planned to further investigate this benefit.
"The reduction in blood pressure was noticeable at one week and sustained through 12 months," Knudson said.
Pitts said study investigators originally had planned to fully engage the device in the control group after 12 months. Now all patients have been made aware of these preliminary results and the study will continue for several more years with all patients receiving full treatment.
Another study finding was that the longer patients had the device turned on, the more effective it was. But even those who didn't meet the prescribed nine hours of daily device use, averaging 6.9 hours of daily use, experienced a loss of 10.5% of their BMI in the treatment arm and 8.6% in the control at 12 months.
Knudson said the company now is taking steps to meet with the FDA to determine an appropriate regulatory path for this treatment with a morbid obesity indication.
Lynn Yoffee, 770-361-4789