Severe acute allergic reaction after switching anti-calcitonin gene-related peptide monoclonal antibodies: A case report

Abstract

Background: Anti-calcitonin gene-related peptide monoclonal antibodies (CGRP-mAbs) are widely used for migraine prevention and are generally considered safe, with rare severe allergic reactions. Switching between CGRP-mAbs is a common strategy for non-responders, although allergic cross-reactivity remains a theoretical concern. We report a rare case of a severe allergic reaction following switching from fremanezumab to galcanezumab. Case presentation: A 68-year-old woman received fremanezumab for migraine prophylaxis. Due to the deterioration of migraine days, the CGRP-mAb was switched from fremanezumab to galcanezumab. Following the galcanezumab injection, the patient experienced skin rash and dyspnea. Discussion: The present case describes a severe allergic reaction after switching CGRP-mAbs. Given the potential for allergic reactions, further research on similar cases and rigorous investigations are required to assess the safety and risks associated with switching CGRP-mAbs.