In a multi-centered, sham-controlled study conducted in the U.S., episodic cluster headache patients using the gammaCore non-invasive vagus nerve stimulation device (nVNS) had a significant and clinically meaningful benefit within 15 minutes of the treatment of the attack, as compared with the sham treatment, and that this benefit was sustained for over an hour.
The paper also reported that nVNS is well tolerated, produced no serious side effects and that the percentage of episodic patients who experienced a successful response to the first attack treated within 15 minutes was triple that of those using the sham: 34.2% versus 10.6% (p<0.01).
After an hour all subjects in the gammaCore group had maintained their successful response. The study also found consistency of effect among responders, with the percentage of episodic subjects in the active arm who experienced success for more than 50% of the attacks was 34.2% versus 14.9% among the sham group (p=0.04).
The study (ACT 1) was one of the largest ever undertaken in cluster headache, one of the worst pain conditions know to medicine, and it was carried out in the US enrolling 150 patients at 20 headache treatment centers.
Patients were divided into two arms during the randomized period: one using a sham device and the other using the gammaCore nVNS device. Patients self-administered the therapy by placing the sham or gammaCore on the skin over the vagus nerve in the neck.
This new treatment has been welcomed by cluster sufferers and clinicians as there are limited therapeutic options for the acute treatment of cluster headache, which afflicts more than 300,000 people in the U.S. In the U.S., only subcutaneous sumatriptan injections and intravenous DHE are approved for acute use; however, DHE is limited to hospital use and the FDA approved labeling for sumatriptan allows a maximum of two doses per day.
As a result, there is a significant unmet need for many patients, including those with frequent attacks–3 to 8 attacks a day–who cannot use injectable sumatriptan to treat every attack due to a separate condition known as medication overuse headache which can be caused by repeated use of triptans.
Following the completion of the double-blind period, the ACT 1 trial included a three-month open label phase during which all patients were permitted to use gammaCore. The results for all the episodic patients–those previously on sham and those previously on gammaCore–were in line with the results from the double blind phase, i.e., patients who had previously used the sham device experienced a significant increase (nearly 2.5 times) in successful responses.
Patient preference was also measured, and over 90% of the patients found the gammaCore device easy to use and most reported they would recommend it to a family member or friend. A similar study is presently being conducted in the EU and will report shortly.
The Journal Headache