Timing of Effect Onset After Restarting Anti CGRP-(Receptor)-Monoclonal Antibodies Following a Mandatory Cessation After One year of Use–A Single Center Retrospective Cohort Study

Background: Calcitonin gene-related peptide (CGRP)-targeted monoclonal antibodies (CGRP-mAbs) effectively prevent migraine, but treatment interruption often leads to symptom recurrence. We evaluated the onset and magnitude of response after restarting CGRP-mAbs following an insurer-mandated cessation after one year of use. Methods: In this single-center retrospective cohort study, we analyzed 42 patients who restarted the same CGRP-mAb after a median pause of 140 days. The main outcomes were change in monthly migraine days (MMD) versus baseline (pre-treatment) and time to achieve a 50% reduction in MMD. Results: Across months 1– 12, reductions in MMD during the second treatment year were comparable to those during the first year (no statistically significant year-by-month differences). Mean time to achieve a 50% reduction in MMD was also comparable in both years (1.84 months in year 2 vs 2.20 months in year 1; P=0.41). Conclusion: In this exploratory cohort, restarting the same CGRP-mAb after an insurer-mandated pause was associated with a comparable reduction in MMD and comparable time to response as during the first treatment year. Keywords: migraine, calcitonin gene-related peptide, monoclonal antibodies, monthly migraine days, treatment interruption, retreatment