ABSTRACT
BACKGROUND: Two randomized, double-blind, sham-controlled trials (ACT1, ACT2) evaluated non-invasive vagus nerve stimulation (nVNS) as acute treatment for cluster headache. We analyzed pooled ACT1/ACT2 data to increase statistical power and gain insight into the differential efficacy of nVNS in episodic and chronic cluster headache. METHODS: Data extracted from ACT1 and ACT2 were pooled using a fixed-effects model. Main outcome measures were the primary endpoints of each study. This was the proportion of participants whose first treated attack improved from moderate (2), severe (3), or very severe (4) pain intensity to mild (1) or nil (0) for ACT1 and the proportion of treated attacks whose pain intensity improved from 2-4 to 0 for ACT2. RESULTS: The pooled population included 225 participants (episodic: n = 112; chronic: n = 113) from ACT1 (n = 133) and ACT2 (n = 92) in the nVNS (n = 108) and sham (n = 117) groups. Interaction was shown between treatment group and cluster headache subtype (p < 0.05). nVNS was superior to sham in episodic but not chronic cluster headache (both endpoints p < 0.01). Only four patients discontinued the studies due to adverse events. CONCLUSIONS: nVNS is a well-tolerated and effective acute treatment for episodic cluster headache. TRIAL REGISTRATION: The studies were registered at clinicaltrials.gov (ACT1: NCT01792817; ACT2: NCT01958125).
Subject(s)
Cluster Headache/diagnosis , Cluster Headache/therapy , Multicenter Studies as Topic/methods , Randomized Controlled Trials as Topic/methods , Vagus Nerve Stimulation/methods , Chronic Disease , Cluster Headache/epidemiology , Double-Blind Method , Humans , Time Factors , Treatment Outcome , Vagus Nerve Stimulation/trendsABSTRACT
Background Clinical observations and results from recent studies support the use of non-invasive vagus nerve stimulation (nVNS) for treating cluster headache (CH) attacks. This study compared nVNS with a sham device for acute treatment in patients with episodic or chronic CH (eCH, cCH). Methods After completing a 1-week run-in period, subjects were randomly assigned (1:1) to receive nVNS or sham therapy during a 2-week double-blind period. The primary efficacy endpoint was the proportion of all treated attacks that achieved pain-free status within 15 minutes after treatment initiation, without rescue treatment. Results The Full Analysis Set comprised 48 nVNS-treated (14 eCH, 34 cCH) and 44 sham-treated (13 eCH, 31 cCH) subjects. For the primary endpoint, nVNS (14%) and sham (12%) treatments were not significantly different for the total cohort. In the eCH subgroup, nVNS (48%) was superior to sham (6%; p < 0.01). No significant differences between nVNS (5%) and sham (13%) were seen in the cCH subgroup. Conclusions Combing both eCH and cCH patients, nVNS was no different to sham. For the treatment of CH attacks, nVNS was superior to sham therapy in eCH but not in cCH. These results confirm and extend previous findings regarding the efficacy, safety, and tolerability of nVNS for the acute treatment of eCH.
