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Investigators found that participants struggled to adhere to the treatment protocol, which required them to administer 3 treatments per day.
Results of a randomized, double-blind, sham-controlled trial of preventive noninvasive vagus nerve stimulation (nVNS) in episodic migraine suggest that adherence to treatment may be a major factor in determining efficacy.
Findings from the 40-week PREMIUM trial were presented at the 2019 American Headache Society Annual Meeting, July 11-14, in Philadelphia, Pennsylvania.
The trial evaluated the efficacy, tolerability, and safety of preventive nVNS therapy with gammaCore in patients with episodic migraine. Patients first entered a 4-week observation run-in period with no study treatment, then a 12-week double-blind period where they were randomly assigned to either nVNS or sham treatment, followed by a 24-week open-label period where all patients were treated with nVNS.
Patients were instructed to administer 2 120-second stimulations to both sides of the neck 3 times per day, 6-8 hours apart. Patients were allowed to use abortive medication if needed, but other prophylactics were not permitted until week 24. Ultimately, the trial evaluated an intent-to-treat population of 332 patients who received ≥1 treatment in the double-blind period.
Ultimately, mean reductions in the number of migraine days from the run-in period to the last 4 weeks of the double-blind period were -2.26 days in the nVNS group (n=165) and -1.80 days in the sham group (n=167; P =.146). The percent of patients who experienced at least a 50% reduction in migraine days was 31.9% in the nVNS group and 25% in the sham group (P =.186). Overall, similar numbers were observed across groups for headache days and acute medication use.
Prompted by suboptimal rates of adherence to the treatment protocol, the investigators conducted an analysis of a modified intent-to-treat population of patients with at least 67% adherence per month. In that population, significant reductions in number of migraine days (-2.27 vs -1.53 days; P =.043), headache days (—2.85 vs –1.99 days; P =.045), and acute medication days (—1.94 vs –1.14 days; P =.039) were observed in the nVNS group (n=138) compared to the sham treatment group (n=140). Adverse events in the treatment group were mostly mild, with application site pain most commonly reported.
Overall, the results did not support a superior effect for nVNS compared to sham treatment for migraine prevention, though those patients who had good adherence did experience statistically significant benefits. Ultimately, the role of adherence and sham response require further investigation to better understand the role of nVNS therapy in migraine prevention.
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Liebler E, Diener H, Goadsby PJ, et al. Non-invasive vagus nerve stimulation for the preventive treatment of episodic migraine: The multicenter, doubleblind, randomized, sham-controlled PREMIUM trial. Presented at: 2019 American Headache Society Annual Meeting. July 11-14, 2019; Philadelphia, PA. Abstract IOR04.