Botox is the only approved prophylactic chronic migraine medication, although anticonvulsants, tricyclic antidepressants, and beta-blockers are often used off-label in chronic migraine, whereas several are on-label for episodic migraine. More effective treatment for chronic migraine is a great unmet need.
Vagal nerve stimulation is approved for epilepsy and depression. Anecdotal reports of epilepsy patients treated with an implanted VNS device who noted reduction in migraine severity led to small studies. Further, the effects of VNS on epilepsy and depression seem to improve with time on treatment.
Much easier than an implanted device would be a patient-controlled, handheld, non-invasive device, which is now in clinical trials. In this recent study, patients self-administered two 2-minute stimulations 5 to 10 minutes apart to the right side of the neck, 3 times a day. There were no safety issues, but the reduction in headache days a month during the 2-month randomized phase compared to placebo controls was not significant. At 6 months, there seemed to be a significant reduction. The patients who completed the 6-month open-label phase may have been “self-selected,” limiting the validity of this finding. Further, maintaining blinding was a challenge, and there was a high discontinuation rate.
Findings in migraine contrast with those in chronic cluster headache, where prophylactic non-invasive vagal nerve stimulation seems to be helpful and cost-effective.
Despite these somewhat disappointing results, a new study, which contains a 9-month open-label period, is in the planning stages.
See Neurology, August 2, 2016, page 529-538. Lead author is Silberstein.