Noninvasive Vagus Nerve Stimulation Slows Cluster Headache

Nancy A. Melville

October 30, 2014

BALTIMORE, Maryland — A novel, noninvasive neurostimulator targeting the vagus nerve improves on treatment of chronic cluster headaches over the current standard of care, according to a new study.

"Patients who used this device for 6 minutes, two times per day had the number of cluster headache attached reduced by 40% per week," said lead author Eric J. Liebler, vice president of scientific, medical and governmental affairs for ElectroCore, LLC, based in Basking Ridge, New Jersey.

"In addition, we saw a 60% reduction in the amount of acute or rescue medication patients used per week for every 2 weeks," he told Medscape Medical News.

The device, called gammaCore (ElectroCore), uses proprietary electrical signals to treat primary headache, and it is based on the technology used with a permanent implant for vagal nerve stimulation that is currently used for epilepsy and depression.

Liebler presented the findings from the Prevention and Acute (PREVA) Treatment of Chronic Cluster Headache study, funded by ElectroCore, here at the American Neurological Association (ANA) 2014 Annual Meeting.

Noninvasive Device

"Our objective was to see if we could turn this concept into a noninvasive device that could be easier to examine and investigate in more patients," Liebler said. "We wanted to specifically test its efficacy in patients with chronic cluster headache, which many consider to be one of the worst forms of primary headache."

The gammaCore neurostimulation device. ElectroCore LLC

The study involved 97 patients who reported more than 16 cluster headache attacks per week, or two to three per day.

After a 2-week assessment period, the patients received active treatment for 1 month with (1) neurostimulation twice daily and as an optional rescue treatment in addition to their current medication (n = 48) or (2) regular standard of care (n = 49), typically consisting of subcutaneous sumatriptan or oxygen.

In the last 2 weeks of the treatment phase, patients randomly assigned to the neurostimulation group reported greater reductions in the number of cluster headache attacks compared to the run-in phase than did patients receiving only standard of care (change, –6.9 vs –2.0; P = .002).

In addition, 37.4% of patients in the neurostimulation group reported a greater than 50% reduction in cluster headache attacks per week, compared to only 8.5% in the standard of care group (P = .0001).

While medication use (sumatriptan) declined in the neurostimulation group by 61.4% from baseline, use of the drug increased 16.6% in the standard-of-care group.

Patients receiving neurostimulation had oxygen use decline by 60.1%, compared with an 11.2% decrease in the standard-of-care group.

Quality-of-life score changes were modest in both groups.

Thirty-one patients reported adverse events, but all were said to be mild or moderate in intensity.

"Some patients reported a mild or transient stiff neck at the time of treatment, but the effects tended to subside when the treatment ends," Liebler said.

While neurostimulation treatments are currently available for headache treatment, the gammaCore is unique in targeting the vagus nerve, Liebler added.

"There are currently two neurostimulation devices for migraine that are approved in the US, including transcranial magnetic stimulation, for the back of the head, and the other for cephaly, involving the trigeminal nerve at the top of the head, but neither targets the vagus nerve, and neither has been studied for chronic cluster headaches."

The gammaCore device is approved for use in Europe, and Liebler noted that three additional randomized controlled trials are testing the therapy against a sham treatment.

European Statement

In response to the increasing number of noninvasive and invasive approaches for the treatment of primary headache, including hypothalamic deep-brain stimulation, occipital nerve stimulation, cervical spinal cord stimulation, vagus nerve stimulation, transcranial direct-current stimulation, repetitive transcranial magnetic stimulation, and transcutaneous electrical nerve stimulation, the European Headache Federation issued a consensus statement on these neuromodulation treatments in October 2013.

Their assessment of the approaches underscored the need for further clinical trials. "In spite of a growing field of stimulation devices in headaches treatment, further controlled studies to validate, strengthen and disseminate the use of neurostimulation are clearly warranted," the group wrote.

"Consequently, until these data are available, any neurostimulation device should only be used in patients with medically intractable syndromes from tertiary headache centers, either as part of a valid study or have shown to be effective in such controlled studies with an acceptable side effect profile."

At the University of Pavia's Pavia Headache Center in Italy, Fabio Antonaci, MD, says he has seen some success with the vagus nerve stimulation approach in some patients.

"I have been prescribing gammaCore since 2013 and have generally received a positive feedback from patients," Dr Antonaci told Medscape Medical News.

He noted that the approach is "slowly increasing in use, but there has not been much discussion of the treatment among headache specialists."

Dr Antonaci said he has not had success with other types of electrostimulation. He noted that in treating cluster headache, the goal is for treatment to be "safe, fast, effective and with few side effects."

A study published by Dr Antonaci and his colleagues in the September issue of the Journal of Headache Pain underscores the long delays that patients with cluster headache often endure before receiving a specialized consultation on their treatment.

In the study of 114 patients with episodic cluster headache, the mean interval between headache onset and the first consultation at a headache center was 4.1 years, and the average diagnostic delay was 5.3 years. Misdiagnoses at first consultation were recorded in 77% of cases.

"Our results emphasize the need to improve specialist education in this field in order to improve recognition of the clinical picture of CH [cluster headache] and increase knowledge of the proper medical treatments for de novo CH," Antonaci and colleagues concluded.

The study was funded by ElectroCore, LLC. Mr Liebler is an employee of ElectroCore, LLC. Dr Antonaci has disclosed no relevant financial relationships.

American Neurological Association (ANA) 2014 Annual Meeting. Abstract M1508. Presented October 13, 2014.

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