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

Efficacy and safety of galcanezumab as a treatment of refractory episodic and chronic cluster headache: Case series and narrative review

BACKGROUND

Galcanezumab, a monoclonal antibody targeting calcitonin gene-related peptide (CGRP), has demonstrated clinical benefit as a preventive treatment of episodic cluster headache (ECH) but not in chronic cluster headache (CCH) to this date. Our objective was to analyze our clinical experience of the compassionate use of galcanezumab in cluster headache and to conduct a narrative review of the published literature.

METHODS

We present a case series of patients with refractory ECH and CCH treated with 240 mg galcanezumab monthly in an outpatient headache clinic. We recorded epidemiologic and clinical data and analyzed the disease evolution after 3 and 6 months. The review was performed following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

We included three patients with ECH who were treated during a refractory cluster bout (mean duration of 83.7 days since the first attack, range 46.0-105.0 days) and six patients with CCH who had a high frequency of attacks (mean 35.8 attacks/week, range 7-56) and refractory to a mean of 5.2 preventive treatments (range, 3-9). In the CCH group, >50% frequency reduction was seen in 83% (5/6 patients) and the number of attacks per week showed a mean reduction of -24.2 at month 3 (range, -6 to -49) and -27.6 at month 6 (range, -7 to -49). In the ECH group, the bout ended a mean 17.3 days (range, 10-28) after galcanezumab administration. One third of patients reported mild adverse events, none of them leading to discontinuation.

CONCLUSION

In conclusion, our clinical experience supports the use of galcanezumab in patients with refractory cluster headache. These results might encourage the possibility of continuing clinical development with randomized controlled trials of anti-CGRP treatments in patients with cluster headache.

Long-term open-label safety study of galcanezumab in patients with episodic or chronic cluster headache

BACKGROUND

CGAR, a Phase 3b open-label study, evaluated the long-term safety of galcanezumab in patients with cluster headache who completed one of two Phase 3 double-blind studies in chronic or episodic cluster headache.

METHODS

Patients (N = 164) received galcanezumab 300 mg subcutaneously up to once a month. Primary endpoint was safety, as assessed by treatment-emergent adverse events, serious adverse events, and suicidality. Other endpoints included discontinuation rates, immunogenicity, efficacy as assessed by the Patient Global Impression of Improvement, and health values.

RESULTS

At baseline, mean (standard deviation) age was 48.3 (9.8) years, 75.0% were men, and 85.4% were white. Treatment-emergent adverse events (n = 119 [72.6%]) were mostly mild-to-moderate, with nasopharyngitis the most commonly reported (22.0%). One of 18 serious adverse events was judged as treatment related (constipation). Two patients (1.2%) reported suicidal ideation. Five patients (3.1%) discontinued due to an adverse event. Eight patients were treatment-emergent anti-drug antibody positive, two of whom were not treatment-emergent anti-drug antibody positive in the parent studies. On the Patient Global Impression of Improvement, ≥81% reported their cluster headache status as very much, much, or a little better at Months 1, 6, and 12. Health value scores generally improved from baseline.

CONCLUSIONS

In this open-label study, galcanezumab was generally well tolerated and improved patient-reported cluster headache status.Trial registration number: NCT02797951; https://clinicaltrials.gov/ct2/show/NCT02797951.