Background and Importance Monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP-mAbs) are used in the prophylaxis of migraine. The therapeutic target is not exactly the same as Erenumab targets the CGRP receptor, whereas Galcanezumab and Fremanezumab target circulating CGRP. However, their relative effects in patients with prior migraine treatment failure remains uncertain.

Aim and Objectives To describe the use, effectiveness and safety of CGRP-mAbs switching in patients with migraine.

Material and Methods Retrospective observational study between 1-September-2019 and 30-September-2022 in a third-level hospital. Data collected: sex, age, comorbidities, CGRP-mAbs prescribed, treatment duration, causes of suspension, adverse reactions (AR), Headache Impact Test (HIT) and Migraine Disability Assessment (MIDAS) scores, average number of migraine days per month (NMDM) and days with triptans at baseline, prior and concomitant preventive drugs. Data were obtained from electronic medical records and patients interviews. The study had been approved by the Ethics Committee. Informed consent was obtained from all participants.

Results Of 167 patients on treatment with CGRP-mAbs, 17.4% (89.7% women, median age: 45.1(37.4–53.8) years) switched to another mAb: Erenumab (38%), Galcanezumab (31%), Fremanezumab (31%). While 75.9% of patients discontinued due to ineffectiveness, 24.1% had AR. Most of them (77.4%) had chronic migraine, 22.6% high-frequency episodic migraine. The main comorbidities were anxious-depressive syndrome (19.3%) and fibromyalgia (12.9%). The average NMDM was 15 ± 7.7 days and 31.0% patients used triptans ≥7 days/month. All patients had >3 prior treatments: beta blockers (87.1%), calcium antagonists (100%), antidepressants (93.5%), antiepileptics (100%) and botulinum toxin (79.3%). Concomitant preventive drugs was used 75.8% of patients, concomitant botulinum toxin in 13.8%. Median treatment duration of the second line: 5(3.3–7) months.

Fifteen patients (51.7%) switched to a third line: Erenumab (6.6%), Galcanezumab (60.0%), Fremanezumab (33.4%). Median treatment duration: 4 (1.7–4) months. The retention rate after the second switch was 93.3%. No AR were observed.

Conclusion and Relevance Some migraine patients who did not respond to a first drug responded initially to the switch, however half of them need to switch to a third mAb. Although non-responders to treatment may profit from a switch of antibody class, more studies are needed to describe which patients will respond to CGRP-mAb switching. Considering the low number of AR, treatment with CGRP-mAbs can be considered safe.

Conflict of Interest No conflict of interest