Effect of Galcanezumab on Weekly Total Pain Burden in Patients With Episodic Cluster Headache

Compared with placebo, galcanezumab may significantly decrease the mean weekly total pain burden in patients with episodic cluster headache, according to findings published in the Journal of Pain Research.

Researchers conducted a post-hoc analysis of a phase 3 randomized, doubleblind, placebo-controlled study on the safety and efficacy of galacanezumab for the prevention of episodic cluster headache (ClinicalTrials.gov identifier NCT02397473).The researchers sought to assess the effect of galcanezumab on the total pain burden in patients with episodic cluster headache. Between 2015 and 2018, patients from 35 sites in Europe and North America were enrolled and randomly assigned in a 1:1 fashion to receive either galacanezumab or placebo once monthly for 8 weeks. The researchers obtained data from an electronic patient-reported outcomes diary to calculate the mean weekly total pain burden for each treatment group. Initial study results showed that the frequency of cluster headache episodes was significantly decreased among patients treated with galacanezumab vs those treated with placebo.

Among a total of 106 patients included in the final analysis, 49 received galcanezumab and 57 received placebo. Patients were aged between 18 and 65 years, and baseline demographics were not significantly different between the two treatment groups. Eligible patients included those who had 4 or more cluster headache episodes at a minimum frequency of once every other day during 7 consecutive days of the prospective baseline period; patients who had more than 8 episodes daily were excluded.

Between weeks 1 and 3, the researchers found that the overall least squares (LS) mean decrease in the mean weekly frequency of cluster headache episodes was significantly greater among patients in the galcanezumab group compared with those in the placebo group. Patients in the galcanezumab group also had a greater overall LS mean decrease in the mean duration per cluster headache episode, though the decrease was not statistically significant (95% CI, 0.07-0.32; P = .20). In addition, the overall LS mean decrease in the total weekly mean severity of cluster headache episodes was numerically, but not statistically significantly, greater among patients in the galcanezumab vs those in the placebo group.

Of note, the researchers found that the LS mean decrease in total weekly pain burden between baseline and weeks 1 to 3 was 11.18 severity-weight hours greater in the galcanezumab group vs the placebo group (95% CI, 0.83-21.53; P =.035). In addition, the mean percent change from baseline in weekly total pain burden was significantly greater with galcanezumab treatment vs placebo (64% vs 31%; mean difference, 33.5%; 95% CI, 10.75-56.21).

After performing 2 sensitivity analyses with adjustment for weighted episode severity scores, the researchers noted that patients in the galcanezumab group had a significantly greater mean decrease in total pain burden compared with those in the placebo group. The researchers calculated the square root of episode severity to weight cluster headache duration and found that the LS mean change from baseline in weekly total pain burden between weeks 1 and 3 decreased by 14.74 and 8.77 severity-weighted hours in the galcanezumab and placebo groups, respectively (mean difference, 5.96; 95% CI, 0.03-11.90).

Weekly total pain burden data showed a moderate to high correlation with each of 3 individual pain components of patients’ episodic cluster headache at baseline, including frequency, duration, and severity. Mean change from baseline in mean weekly total pain burden was numerically greater in the galcanezumab group vs the placebo group in the weekly mean frequency of cluster headache episodes after adjustment for changes from baseline.

Study limitations included those inherent to post-hoc analyses, its small sample size, the arbitrary scoring of pain severity on a 5-point scale, and the potential effect of acute treatments on the duration and severity of cluster headache episodes.

“Galcanezumab significantly [decreased the] mean weekly total pain burden compared with placebo in patients with episodic cluster headache,” the researchers noted. In addition, “total pain burden may provide a holistic measure of pain [in patients with] episodic cluster headache,” the researchers concluded.

Disclosure: Some author(s) declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of disclosures.

Reference

Andrews JS, Kudrow D, Rettiganti M, et al. Impact of galcanezumab on total pain burden: A post hoc analysis of a phase 3, randomized, double-blind, placebo-controlled study in patients with episodic cluster headache. J Pain Res. 2021;8;14.2059-2070. doi: 10.2147/JPR.S305066