Anti‑CGRP monoclonal antibodies in resistant migraine: preliminary real-world effectiveness and clinical predictors of response at two years.

Background: Monoclonal antibodies targeting calcitonin gene-related peptide (anti-CGRP mAbs) have shown clinical effectiveness and safety in randomized clinical studies. However, long-term studies in clinical practice remain limited.

Aim: To assess the long-term effectiveness, clinical predictors and safety of three anti-CGRP mAbs (erenumab, galcanezumab, fremanezumab) in resistant migraine patients.

Method: A single-center retrospective study was conducted from December 2019 to June 2023 involving 120 resistant migraine patients who received at least a month of anti-CGRP mAbs treatment. Patients completed a headache diary that included monthly acute medication intake (MAM), monthly migraine days (MMD), adverse events as well as completed Patient-Reported Outcome questionnaires (MIDAS [Migraine Disability Assessment] and Headache Impact Test 6 [HIT-6]). The number of patients achieving a ≥ 50% reduction in monthly migraine days was determined and classified as ≥ 50% responders, and baseline parameters and logistic regression between responders and non-responders were analyzed to identify potential predictors of response. Adverse events were registered in every follow-up.

Results: Treatment with anti-CGRP mAbs led to reductions in MIDAS, HIT-6, MMD and MAM from baseline to 6-24 months. At 6-12 months, responders (61% and 57%, respectively) exhibited lower baseline MMD and MAM. Medication overuse  was associated with non-responders from 6 to 24 months and it was identified as a negative predictor of treatment effectiveness (OR 0.23, 95% CI 0.07-0.74; p = 0.014).

Conclusion: Anti-CGRP mAbs prove effectiveness and safety over a 24-month period in a RM population. Patients with no medication overuse and lower basal MMDs and MAM may respond better to anti-CGRP mAbs.