Celia Romero del Rincón

Background and purpose According to the latest European guidelines, discontinuation of monoclonal antibodies against calcitonin gene‐related peptide (anti‐CGRP MAb) may be considered after 12–18 months of treatment. However, some patients may worsen after discontinuation. In this study, we assessed the response following treatment resumption. Methods This was a prospective study conducted in 14 Headache Units in Spain. We included patients with response to anti‐CGRP MAb with clinical worsening after withdrawal and resumption of treatment. Numbers of monthly migraine days (MMD) and monthly headache days (MHD) were obtained at four time points: before starting anti‐CGRP MAb (T‐baseline); last month of first treatment period (T‐suspension); month of restart due to worsening (T‐worsening); and 3 months after resumption (T‐reintroduction). The response rate to resumption was calculated. Possible differences among periods were analysed according to MMD and MHD. Results A total of 360 patients, 82% women, with a median (interquartile range [IQR]) age at migraine onset of 18 (12) years. The median (IQR) MHD at T‐baseline was 20 (13) and MMD was 5 (6); at T‐suspension, the median (IQR) MHD was 5 (6) and MMD was 4 (5); at T‐worsening, the median (IQR) MHD was 16 (13) and MMD was 12 (6); and at T‐reintroduction, the median (IQR) MHD was 8 (8) and MHD was 5 (5). In the second period of treatment, a 50% response rate was achieved by 57.4% of patients in MHD and 65.8% in MMD. Multivariate models showed significant differences in MHD between the third month after reintroduction and last month before suspension of first treatment period ( p < 0.001). Conclusion The results suggest that anti‐CGRP MAb therapy is effective after reintroduction. However, 3 months after resumption, one third of the sample reached the same improvement as after the first treatment period.