LAUSR

OBJECTIVES To assess frequency and characteristics of late responders (>12 weeks) to monoclonal antibodies (mAbs) targeting the calcitonin gene-related peptide (CGRP). METHODS This is a multicenter (n=16), prospective, real-life study, considering all consecutive adults with high frequency or chronic migraine treated with anti-CGRP mAbs for >24 weeks. We defined responders patients with a >50% reduction from baseline in monthly migraine/headache days at weeks 9-12, and late responders those achieving a >50% reduction only afterwards. RESULTS 771 people with migraine completed >24 weeks of anti-CGRP mAbs treatment. Responders at 12 weeks were 65.6% (506/771) of the patients, while non-responders were 34.4% (265/771). 146 out of the 265 non-responders (55.1%) at 12 weeks responded afterward (late responders): they differed from responders for higher BMI (+0.78, 95%CI [0.10;1.45]; p=0.024), more frequent treatment failures (+0.52, 95%CI [0.09;0.95]; p=0.017) and psychiatric comorbidities (+10.1%, 95%CI [0.1;0.20]; p=0.041), and less common unilateral pain, alone (-10,9%, 95%CI [-20.5;-1.2]; p=0.025) or in combination with unilateral cranial autonomic symptoms (-12.3%, 95%CI [-20.2;-3.9]; p=0.006) or allodynia (-10.7, 95%CI [-18.2;-3.2]; p=0.01) . DISCUSSION Half of non-responders to anti-CGRP mAbs at 12 weeks are indeed late responders. Efficacy of anti-CGRP mAbs should be assessed at 24 weeks while treatment duration should be extended beyond 12 months.