MEDICAL DEVICE INNOVATION - Medical Device Daily

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VBLOC blocks signals between
brain and gut for weight loss
By AMANDA PEDERSEN
Medical Device Daily Staff Writer
Brain to stomach, brain to stomach, ALERT: food is on
the way, start expanding.
Stomach to brain (as food is consumed): not satisfied
yet, send more food.
This is essentially the conversation that takes place
between a person’s brain and stomach, usually from the
minute the nose senses food. And this communication is
the reason that EnteroMedics (St. Paul, Minnesota) has
developed its alternative to weight-loss surgery: a technology
designed to slow down or even block the signals from
the brain to the stomach and back again.
EnteroMedics recently reported interim data from the
VBLOC-RF2 feasibility study of its VBLOC vagal blocking
therapy device, the Maestro. The study, taking place at two
sites in Europe and one in Australia and including 38
implanted subjects, is designed to evaluate the system’s
safety and efficacy.
Follow-up data show excess weight loss of 37.6% in
nine patients at 18 months of VBLOC therapy, 28.1% in 17
patients at 12 months of therapy and 17.9% in 35 patients at
six months of therapy, according to the company. Also, no
deaths or unanticipated adverse device events have been
reported.
“VBLOC therapy is designed to produce weight loss, in
part, by controlling the feelings that lead patients to fail at
losing weight, including hunger and a lack of feeling full,”
said Mark Knudson, PhD, president/CEO of the company.
“These results are an encouraging sign that significant
weight loss, occurring over an extended period of time, can
take place without the serious side effects and adverse
lifestyle impact seen in other obesity procedures.
“We continue to look forward to releasing the results of
our randomized pivotal trial in the second half this year.”
VBLOC therapy is a high-frequency blocking technology,
not a stimulation therapy as used by other companies in
the neuromodulation space, Greg Lea, the company’s senior
VP and CFO, told Medical Device Daily.
Lea explained that surgeons use to routinely cut the
vagus nerves near the stomach to treat ulcers, a procedure
known as a vagotomy. When they did this they noticed right
away that patients lost their appetite and started to lose
weight, Lea said. So, in 2002, based on an analysis of the
vagus nerve’s control of food intake and processing,
EnteroMedics was founded to develop a therapy to treat,
primarily, obesity.
VBLOC therapy is delivered through leads implanted
laparoscopically in the abdomen to intermittently block
vagal nerve trunks. High-frequency, low-energy electrical
impulses are delivered by an implantable system to block
MEDICAL DEVICE INNOVATION 2010
the messages conveyed through the vagal nerves. If
desired, the VBLOC delivery system can be removed if, and
previous studies in animals have indicated that it does not
damage or permanently affect the vagal nerves.
Like other weight-loss procedures, the benefit of losing
weight is complemented by an improvement in co-morbidities
so frequently associated with obesity, such as Type
2 diabetes and hypertension. But unlike the laparoscopic
banding and gastric bypass procedures, the improvements
in co-morbidities do not correspond to weight loss, Lea
said. He said in many patients the minute the VBLOC therapy
is applied, or soon thereafter, the patient’s hypertension
improves, as well as their diabetic condition.
“In our case, what we’re seeing is that those conditions
improve prior to weight loss . . . it’s very encouraging,” he
said.
The company reported the co-morbidity data earlier
this month at the J. P. Morgan conference. And it also reported
its 18-month follow-up data showing that weight loss is
“very consistent” with what patients experience in banding
procedures, with a “much better” safety profile, Lea said.
According to the data, 10 patients with diabetes showed
a statistically significant reduction of 1.1 percentage points,
from 8.2% at baseline to 7.1% at four weeks; and 15 patients
with both systolic and diastolic hypertension, which was
either untreated or controlled with drugs, showed statistically
significant reductions of 13.9 mm Hg in systolic pressure
and 10.7 mm Hg in diastolic pressure at four weeks.
The improvements in blood pressure are maintained
through six months, the company noted.
EnteroMedics’ study outside the U.S. started out with
38 patients enrolled, but some patients elected to drop out,
Lea said, because the company had to offer a procedure in
laparoscopic banding or gastric bypass if they didn’t like
the VBLOC procedure.
“Many of them used our procedure to jump the queue,
getting into our study and then six months later saying ‘give
me lap band’,” he said. “So we had some fall out, but we still
anticipate somewhere between 20 to 25 patients in the trial.”
In addition to the VBLOC-RF2 study, the Maestro system
is being used in the company’s pivotal EMPOWER clinical
trial, a randomized, prospective, double-blind, placebocontrolled
study being conducted in the U.S. and Australia
under an FDA Investigational Device Exemption. The trial
was fully enrolled at 15 sites (13 in the U.S. and two in
Australia) with 294 patients in September.
Lea said that one-third of the 294 patients in the trial
have the device implanted but not turned on while two
thirds have the device turned on. The study blind – which
remains in place for 12 months after activation of therapy in
the experimental arm – is expected to lift in the second half
of this year, EnteroMedics noted.
Another company, GI Dynamics (Lexington,
Massachusetts) also has a device designed to treat diabetes
independently of weight loss.
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