The US Food and Drug
Administration on Thursday gave its approval to a new implanted device that
lowers the rate of seizures among people with epilepsy.
detects abnormal electrical activity in the brain and responds by delivering
electrical stimulation intended to normalise brain activity before the patient
experiences seizure symptoms," Christy Foreman, director of the Office of
Device Evaluation in the FDA's Centre for Devices and Radiological Health, said
in an agency news release.
Kelly O'Brien, 28, has
epilepsy and said the device – called the RNS Stimulator – has been
"It has given me an
independence I did not have before," said O'Brien, who lives in Columbus,
Ohio. "Since getting the device, my seizures have stopped and I am doing
things I was not able to do in the past. The biggest thing is, I'm now able to
Short-circuits nerve cells
Smaller and thinner than an
implantable heart defibrillator, the battery-powered, programmable device is
placed just under the skull during surgery. Electrodes reach from the device to
the one or two places in the patient's brain that create the abnormal
electrical activity that causes seizures. The RNS System, made by
California-based company NeuroPace, works by short-circuiting nerve cells in
that area to normalize brain activity before a seizure is triggered.
The FDA decision follows a
unanimous vote in February in favour of the device by an FDA panel that
assessed its effectiveness and safety. According to the FDA, the new
pre-marketing approval granted to the RNS System was based on a three month
clinical trial involving 191 patients whose epilepsy had not responded to drug
Reductions in seizure
The study found that
patients with a switched-on device saw their rate of monthly seizures fall by
an average 38%, compared to a 17% reduction among patients who had received the
implant but had had it switched off. For some patients, the device worked
especially well, according to the FDA – 29% of patients with a switched-on
device saw the number of seizures they experienced per month fall by half.
Reductions in seizure
frequency linked to the RNS System continued over a 2-year follow-up period,
the agency added.
"These are patients
who have no other resort for treatment of their epilepsy, and this device
offers new hope for them," said Dr Dileep Nair, an epileptologist and
Section Head of the Cleveland Clinic's Epilepsy Centre. The centre was one of
15 sites in the United States to participate in clinical trials.
"We badly need new,
effective therapies for the hundreds of thousands of people in this country as
well as the millions around the world who live with uncontrolled
seizures," Warren Lammert, chairman of the patient advocacy group the
Epilepsy Foundation, said in a Neuropace news release.
He said the new device
"integrates the best of technology and neurology, and is an important new
treatment option for these individuals and their families."
NeuroPace President and CEO
Frank Fischer said, "This is the first responsive neuro-stimulation system
ever designed. Our long-term results show that patients have a reduction of 50%
or more in their seizure frequency, compared to baseline, and a lessening of
The device is designed
specifically for people 18 and older with partial-onset epilepsy, which occurs
when one or more fixed locations in a person's brain start the cascade of nerve
firing that creates a seizure.
NeuroPace has also done two
studies involving a total of 256 patients who were monitored for a period of
between two and nine years, without any significant problems, according to
Epilepsy is a brain
disorder in which a person suffers repeated seizures over time. It affects more
than 2 million Americans, according to the Epilepsy Foundation, making it the
third most common neurological disorder in the United States, after Alzheimer's
and stroke. Seizures are episodes of disturbed brain activity that cause changes
in attention or behaviour. Brain cells keep firing instead of acting in an
organized way. The malfunctioning electrical system of the brain causes surges
of energy that can cause a person to have muscle contractions or to black out.
Physicians can modify the
programming of the device even after it has been implanted, to reflect a
patient's needs over time, Fischer said. They can also observe the brain
activity of a patient from a laptop computer in their office – to help them
manage a patient's treatment, he said.
Speaking in February at the
time of the FDA panel's approval, Fischer said it was too soon to say what the
device might cost. However, comparable systems for heart problems range in
price from $30 000 to $35 000, not including the cost of the surgery to implant
the device. The battery that powers the epilepsy device lasts about three
years. When it fails, a new device has to be substituted in a 30-to-60-minute
outpatient surgical procedure, Fischer said.
The FDA did note some
important safety issues with the RNS System. Users cannot undergo MRI
procedures, or other procedures such as diathermy (electrically induced heat),
electroconvulsive ("electroshock") therapy or transcranial magnetic
stimulation. "The energy created from these procedures can be sent through
the neuro-stimulator and cause permanent brain damage, even if the device is
turned off," the FDA explained.
Health issues that could
also occur include infections at the site of the implant and premature battery
depletion, the FDA said.
For more on epilepsy, visit
the Epilepsy Foundation.