Reversion From Chronic Migraine to Episodic Migraine in Patients Treated With Fremanezumab: Post Hoc Analysis From HALO CM Study

Background: Migraine preventive medications are used to reduce headache frequency, severity, and duration. In patients with chronic migraine (CM), reversion to episodic migraine (EM) is an important treatment goal. Objective: To evaluate the effect of fremanezumab on the rate of reversion from CM to EM. Methods: This phase 3, randomized, double-blind, placebo-controlled, parallel-group trial included a 28-day pretreatment period and a 3-month treatment period. Patients with CM received subcutaneous fremanezumab quarterly (675 mg at baseline) or monthly (675 mg at baseline; 225 mg at Weeks 4 and 8), or placebo. Post hoc analyses evaluated the proportion of patients who reverted from CM to EM, defined as either a reduction to an average of <15 headache days per month during the 3-month treatment period or a reduction to <15 headache days per month in all 3 months of the treatment period. Results: This analysis included data from 1088 CM patients (quarterly, n = 366; monthly, n = 365; placebo, n = 357). More fremanezumab-treated patients with CM reverted to EM using either the monthly average number of headache days criteria for reversion (quarterly: 50.5% [185/366], P =.108; monthly: 53.7% [196/365], P =.012; vs placebo: 44.5% [159/357]) or the monthly headache day count at Months 1, 2, and 3 criteria for reversion (quarterly: 31.2% [114/366], P =.008; monthly: 33.7% [123/365], P =.001; vs placebo: 22.4% [80/357]). Patients with CM who reported previous topiramate or onabotulinumtoxinA use, concomitant preventive medication use, or medication overuse were less likely to revert to EM. Conclusions: Fremanezumab may offer the benefit of reversion from CM to EM, based on a reduction in the number of headache days over 3 months of treatment.