AT SUMMIT IN NEUROLOGY & PSYCHIATRY
WASHINGTON (FRONTLINE MEDICAL NEWS) – Encouraging data on an external vagal nerve stimulator and a minimally invasive system that targets the sphenopalatine ganglion are propelling the two neuromodulation devices toward approval for headache, Stewart J. Tepper, MD, said at the Summit in Neurology & Psychiatry.
“This would bring to four the number of devices we now have available to us to treat headache,” said Dr. Tepper , director of research at the Dartmouth Headache Clinic, Lebanon, N.H. Two types are already available in the United States: a trigeminal nerve stimulator approved for migraine prevention and two brands of transcranial magnetic stimulators approved for acute treatment of migraine with aura.
Noninvasive vagal nerve stimulator
The gammaCore device (electroCore Medical) could be approved for cluster headache this year, Dr. Tepper said. A company spokesman said the company submitted its pivotal trial data to the Food and Drug Administration in 2015, but couldn’t offer any insight into how far the process has progressed.
“That application is currently under review, and we look forward to the FDA’s decision when it comes,” Eric Liebler , electroCore vice president for scientific, medical, and governmental affairs, said in an interview.
The gammaCore device is an external vagal nerve stimulator already approved in Canada and Europe for the treatment of primary headache disorders. In April 2016, it was approved in the United Kingdom as well, Dr. Tepper said at the meeting, sponsored by the Global Academy for Medical Education. Global Academy and this news organization are owned by the same company.
The device is a small, handheld unit that the patient uses twice each day, and which transmits mild current to the vagal nerve. It’s activated over the carotid pulse point on the neck for about 90 seconds. It’s thought to work by suppressing excessive extracellular glutamate and suppressing cortical spreading depression, Dr. Tepper said.
The most recent data for the gammaCore device, presented at the annual meeting of the American Headache Society (AHS) in June, suggest that it could also be beneficial in chronic headache and in menstrual migraine.
A 12-week, open-label study of 51 women with menstrual migraine looked at pain intensity, analgesic use, and migraine disability. Women used the device prophylactically, six stimulations each day for 3 days before and after the onset of menstruation. The mean number of menstrual migraine days each month declined significantly from 7.2 to 4.7. About 40% of the group had at least a 50% reduction in migraine days. Pain intensity also decreased significantly, as well as did the number of doses of analgesics. There were significant improvements on both the Headache Impact Test and Migraine Disability Assessment . One subject discontinued treatment due to dizziness during stimulation.
An 8-week study on cluster headache was published in May and updated at the AHS meeting. Investigators randomized 87 patients with cluster headache to standard therapy alone or plus the gammaCore device. The PREVA (Prevention and Acute treatment of chronic cluster headache) study determined that dual therapy reduced the number of weekly attacks by four, compared with standard therapy. A total of 40% of patients experienced at least a 50% response rate, compared with 8% of controls. A subanalysis presented at the AHS meeting showed that 18% of the dual-therapy group experienced at least a 75% response rate.
Implantable sphenopalatine ganglion stimulator
Dr. Tepper is particularly excited about the Pulsante device , an implantable, wireless sphenopalatine ganglion (SPG) stimulator manufactured by Autonomic Technologies, which he called “a dramatic change in paradigm,” for the treatment of cluster headaches.
The system consists of a neurostimulator about the size of an almond and a lead with six electrodes. It’s inserted under local anesthetic via a small incision in the upper gum on the side in which the patient experiences symptoms. The electrodes are positioned along the SPG nerve and the neurostimulator is affixed to the zygomatic process.
A handheld wireless controller placed against the cheek activates the device and controls the intensity of stimulation, which is thought to work by blocking signals to the postganglionic parasympathetic fibers. Those fibers innervate facial structures and the cerebral and meningeal blood vessels and are implicated in the pain and accompanying autonomic symptoms of a cluster headache attack.
“You can literally see this device working right before your eyes,” he said. “Patients having a cluster attack will exhibit ptosis, red watering eyes, nose running, and as soon as the device is turned on, you see the lid come up, the eye turn white, and the tearing and runny nose stop. This is an objective correlate to a subjective pain response. It’s dramatic and exciting.”
The pivotal Pathway CH-1 study that led to European Union approval was small – just 43 patients – but found that half the cluster attacks could be terminated within 15 minutes of onset. About half of the patients, who had a decades-long history of cluster headaches, experienced close to a 90% reduction in attack frequency.
The latest Pulsante data were also presented in June at the AHS meeting. Two papers – one with 24-month data from the pivotal trial, and one with 12-month data from an ongoing registry study – were overwhelmingly positive, Dr. Tepper said.
The 24-month follow-up data to the pivotal study found that 61% of patients experienced a therapeutic response to SPG stimulation. Most attacks (79%) responded to stimulation alone without the need for abortive therapy. Most patients (64%) also experienced clinical improvements in preventive medication use. Twenty-one were able to reduce or even eliminate the use of preventive medications.
The registry study provided data on 85 patients. Of these, 68% experienced at least a 50% reduction in attack frequency; some reported close to a 90% reduction. A third of patients actually experienced some period of remission, and some patients who were not initially responders became responders after a year of treatment. Acute medication use declined by 52% overall and by 82% in those considered therapeutic responders.
“These data are extremely encouraging,” Dr. Tepper said.
Adverse events are minimal and most are related to implantation. A safety study of 99 patients found that adverse events included sensory disbranch, pain, and swelling, which resolved in 90 days.
The U.S. Pathway CH-2 Cluster Headache Study is now underway and aims to enroll 120 patients. “If the data are positive on this, the company will go ahead and pursue U.S. approval,” Dr. Tepper said.
Dr. Tepper has received personal remuneration and research funding from a number of pharmaceutical companies. He holds stock in Autonomic Technologies.
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