Unveiling the Efficacy and Safety of Erenumab, a Monoclonal Antibody Targeting Calcitonin Gene-related Peptide (CGRP) Receptor, in Patients with Chronic and Episodic Migraine: A GRADE-assessed Systematic Review and Meta-analysis of Randomized Clinical Trials with Subgroup Analysis

Background Migraine is a highly prevalent and disabling disease, affecting nearly 14% of the global population. Preventive medications involve drugs like beta-adrenergic blockers, antidepressants, and anticonvulsants. However, these drugs lacked effectiveness, and patients showed poor tolerance and low adherence to them. Erenumab, a calcitonin gene-related peptide receptor blocker, has recently shown promising results in migraine management. In this meta-analysis, the efficacy of Erenumab is investigated by employing a subgroup analysis approach. Methods A systematic search of six electronic databases was conducted until July 2024. Review Manager 5.4 software was utilized for the analysis, which was based on either weighted mean difference (MD) and standard deviation (SD) for continuous outcomes or risk ratio (RR) for dichotomous outcomes, with a confidence interval (CI) of 95%. A P-value < 0.05 indicated statistical significance. The study was registered on PROSPERO with registration number CRD42024573300. Additionally, we conducted subgroup analyses and assessed the quality of evidence using GRADE. Results A total of 20 randomized controlled trials (n = 5212) were included in our analysis. At three months, Erenumab showed statistically significant improvements in monthly migraine days (MMD), monthly acute migraine-specific medication days (MSMD), Headache Impact Test (HIT-6) score, and ≥ 50% reduction from baseline in MMD (MD: -1.78, 95% CI: [-2.37 to -1.20], P < 0.00001), (MD: -1.36, 95% CI: [-1.92 to -0.81], P < 0.00001), (MD: -2.83, 95% CI: [-3.83 to -1.82], P < 0.00001), and (RR: 1.52, 95% CI: [1.31 to 1.76], P < 0.00001), respectively. Subgroup analysis revealed that Erenumab was significantly more effective in patients with prior preventive treatment failures compared to patients with no prior failure. No significant difference in Erenumab`s response existed between episodic and chronic migraine or between 140 mg and 70 mg, except for MSMD in dose subgrouping. Only constipation and injection-site pain emerged as significant adverse effects in the Erenumab group. Conclusions This meta-analysis found that Erenumab significantly reduced migraine attack frequency, medication days, and physical impairment. It was more effective for patients with prior treatment failures. The 140 mg dose showed better MSMD reduction than 70 mg. Erenumab's safety profile was similar to that of placebo, with only constipation and injection-site pain noted.