Discontinuing monoclonal antibodies targeting CGRP pathway after one-year treatment: an observational longitudinal cohort study

BACKGROUND: Monoclonal antibodies anti-calcitonin gene-related peptide (mAbs anti-CGRP) pathway are effective and safe on migraine prevention. However, some drug agencies limited these treatments to one year due to their high costs. This study aimed at evaluating the effect of discontinuing mAbs anti-CGRP on monthly migraine days (MMDs) and disability in high-frequency episodic (HFEM) and chronic migraine (CM) patients. METHODS: This observational longitudinal cohort study was conducted at 10 Italian headache centres. Consecutive adult patients were followed-up for three months (F-UP1–3) after discontinuation of a one-year erenumab/galcanezumab treatment. The primary endpoint was the change in F-UP MMDs. Secondary endpoints included variation in pain intensity (Numerical Rating Scale, NRS), monthly acute medication intake (MAMI), and HIT-6 scores. We also assessed from F-UP1 to 3 the ≥50% response rate, relapse rate to CM, and recurrence of Medication Overuse (MO). RESULTS: We enrolled 154 patients (72.1% female, 48.2 ± 11.1 years, 107 CM, 47 HFEM); 91 were treated with erenumab, 63 with galcanezumab. From F-UP1 to F-UP3, MMDs, MAMI, NRS, and HIT-6 progressively increased but were still lower at F-UP3 than baseline (Friedman’s analysis of rank, p < .001). In the F-UP1–3 visits, ≥50% response rate frequency did not differ significantly between CM and HFEM patients. However, the median reduction in response rate at F-UP3 was higher in HFEM (− 47.7% [25th, − 79.5; 75th,-17.0]) than in CM patients (− 25.5% [25th, − 47.1; 75th, − 3.3]; Mann-Whitney U test; p = .032). Of the 84 baseline CM patients who had reverted to episodic migraine, 28 (33.3%) relapsed to CM at F-UP1, 35 (41.7%) at F-UP2, 39 (46.4%) at F-UP3. Of the 64 baseline patients suffering of medication overuse headache ceasing MO, 15 (18.3%) relapsed to MO at F-UP1, 26 (31.6%) at F-UP2, and 30 (42.3%, 11 missing data) at F-UP3. Lower MMDs, MAMI, NRS, and HIT-6 and higher response rate in the last month of therapy characterized patients with ≥50% response rate at F-UP1 and F-UP3 (Mann-Whitney U test; consistently p < .01). CONCLUSION: Migraine frequency and disability gradually increased after mAbs anti-CGRP interruption. Most patients did not relapse to MO or CM despite the increase in MMDs. Our data suggest to reconsider mAbs anti-CGRP discontinuation.