Alopecia signals associated with calcitonin gene‐related peptide inhibitors in the treatment or prophylaxis of migraine: A pharmacovigilance study

STUDY OBJECTIVE: Although rarely observed in clinical trials, alopecia has been reported in migraine patients treated with calcitonin gene-related peptide (CGRP) inhibitors during the postmarketing period. This study sought to assess whether CGRP inhibitors are associated with disproportionate alopecia reporting relative to other drugs including those indicated for migraine treatment or prophylaxis in a real-world setting. DESIGN: Retrospective disproportionality analysis. DATA SOURCE: Spontaneous adverse events reported to the United States Food and Drug Administration Adverse Event Reporting System (FAERS) through the fourth quarter of 2021. MEASUREMENTS AND MAIN RESULTS: Thirteen Medical Dictionary for Regulatory Activities preferred terms were used to define alopecia cases in FAERS. Disproportionality was measured by calculating proportional reporting ratios (PRR) and 95% confidence intervals (CI). A PRR >2.0 with a lower 95% CI >1.0 and ≥3 cases was considered a positive signal. During the study period, CGRP inhibitors were reported as suspect products in 55,994 adverse events including 1827 (3.26%) alopecia cases. Compared with all other drugs across FAERS, alopecia signals were detected for the collective CGRP inhibitor class (PRR 4.06; 95% CI 3.88-4.25) and fremanezumab (PRR 5.42; 95% CI 4.66-6.29), erenumab (PRR 4.29; 95% CI 4.05-4.54), galcanezumab (PRR 4.11; 95% CI 3.78-4.48), and eptinezumab (PRR 2.06; 95% CI 1.25-3.40) individually. CGRP inhibitors were consistently associated with alopecia signals relative to triptans (PRR 12.46; 95% CI 10.22-15.18) and celecoxib (PRR 3.50; 95% CI 3.19-3.83), but not in comparison with anticonvulsants, onabotulinumtoxinA, or beta-blockers across analyses. Within the CGRP inhibitor class, an alopecia signal was observed for biologics relative to drugs (PRR 6.11; 95% CI 3.79-9.87). CONCLUSION: Significant alopecia signals were identified for CGRP inhibitors relative to all other drugs and certain comparator migraine therapies based on adverse events reported to FAERS, with CGRP-targeting biologics primarily driving disproportionate reporting. Future observational data will be necessary to better characterize the potential association between real-world use of CGRP inhibitors and incident alopecia in patients with migraine.