Galcanezumab add-on in refractory cluster headache. A case series

Cluster headache (CH), a highly disabling condition, lacks disease-specific, 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). In this case series, we systematically monitored the efficacy and safety outcomes of adjunctive therapy in 11 people with refractory CH (failure of ≥ 3 prophylactic treatments; eCH n = 5, cCH, n = 6) who received galcanezumab (120-360 mg monthly) for 3 consecutive months. All participants received intermediate treatment with oral steroids or a great occipital nerve block ≥ 2 months before starting galcanezumab treatment. 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. These data, along with those of previous real-world reports, suggest that galcanezumab may help people with refractory CH as an add-on treatment.