Predictors of response to anti-CGRP monoclonal antibodies: a 24-week, multicenter, prospective study on 864 migraine patients

BACKGROUND AND OBJECTIVES: The identification of predictors of response to antiCGRP mAbs could favor tailored therapies and personalized treatment plans. This study is aimed at investigating predictors of ≥ 50%, ≥ 75% and 100% response at 24 weeks in patients with high-frequency episodic (HFEM: 8-14 days/month) or chronic migraine (CM). METHODS: This is a large, multicenter, cohort, real-life study. We considered all consecutive adult patients affected by HFEM or CM who were prescribed antiCGRP mAbs for ≥ 24 weeks in 20 headache centers. Patients were interviewed face-to-face using a shared semi-structured questionnaire carefully exploring socio-demographic and clinical characteristics. Patients received subcutaneous erenumab (70 mg or140 mg, monthly), galcanezumab (120 mg monthly, following a 240 mg loading dose), or fremanezumab (225 mg, monthly or 675 mg, quarterly) according to drug market availability, physician's choice, or patient's preference. The primary endpoint of the study was the assessment of ≥ 50% response predictors at 24 weeks. Secondary endpoints included ≥ 75% and 100% response predictors at 24 weeks. RESULTS: Eight hundred sixty-four migraine patients had been treated with antiCGRP mAbs for ≥ 24 weeks (erenumab: 639 pts; galcanezumab: 173 pts; fremanezumab: 55 pts). The ≥50% response (primary endpoint) in HFEM was positively associated with unilateral pain (UP) + unilateral cranial autonomic symptoms (UAs) (OR:4.23, 95%CI:1.57-11.4; p = 0.004), while in CM was positively associated with UAs (OR:1.49, 95%CI:1.05-2.11; p = 0.026), UP + UAs (OR:1.90, 95%CI:1.15-3.16; p = 0.012), UP + allodynia (OR:1.71, 95%CI:1.04-2.83; p = 0.034), and negatively associated with obesity (OR:0.21, 95%CI:0.07-0.64; p = 0.006). The 75% response (secondary endpoint) was positively associated with UP + UAs in HFEM (OR:3.44, 95%CI:1.42-8.31; p = 0.006) and with UP + UAs (OR:1.78, 95%CI:1.14-2.80; p = 0.012) and UP + allodynia (OR:1.92, 95%CI:1.22-3.06; p = 0.005) in CM. No predictor of 100% response emerged in patients with HFEM or CM. CONCLUSIONS: A critical evaluation of headache characteristics indicating peripheral or central sensitization may help in predicting responsiveness to antiCGRP mAbs in HFEM and CM. A more precise pain profiling may represent a steppingstone for a mechanism-based approach and personalized treatment of migraine with compounds targeting specific molecular mechanisms.