Galcanezumab Add-on in Refractory Cluster Headache

Abstract Background: Cluster headache (CH), currently one of the most painful conditions, lacks a well-established, disease specific, and mechanism-based prophylactic treatment. Galganezumab, a monoclonal antibody targeting the calcitonin gene-related peptide, reduced the weekly attacks of CH in one randomized, placebo-controlled trial for the prevention of episodic CH (eCH), but this effect was not detected in people with chronic CH (cCH). Objective: To explore the efficacy and safety of galcanezumab for the prevention of CH in people with refractory CH in a real-world setting. Methods: In this observational study, we systematically monitored the efficacy and safety outcomes of adjunctive therapy in patients with refractory CH (failure of ≥3 prophylactic treatments) who received galcanezumab (120–360 mg monthly) for 3 consecutive months. A detailed headache diary with monthly in-person follow-ups was used. All participants received intermediate treatment with oral steroids or a great occipital nerve block ≥2 months before starting galcanezumab treatment. Results: Data from 11 people with CH (eCH n=5, cCH, n=6) were collected. After galcanezumab treatment, the average number of weekly CH attacks and weekly days with any symptomatic treatment for CH decreased significantly from 16.0±9.4 and 6.50±3.59 before treatment to 1.8±1.32 (p=0.002) and 1.8±3.36 (p=0.001) at month 3 of treatment, respectively.Two participants with cCH showed no change in the number of attacks with galcanezumab. No serious adverse events were recorded. Conclusion: These data, along with those of previous real-world reports, suggest that galcanezumab may help people with refractory CH as an add-on treatment.