Efficacy of Erenumab for Migraine Prevention in Japanese Patients with Episodic and Chronic Migraine: Results of a Post-Hoc Pooled Analysis

INTRODUCTION: Erenumab, a fully human monoclonal antibody against the calcitonin gene-related peptide receptor, is approved in Japan for the prevention of adult migraine. This post-hoc analysis evaluated the efficacy of erenumab in Japanese patients with low-frequency episodic migraine (LFEM) versus those with high-frequency episodic migraine (HFEM) and chronic migraine (CM). METHODS: A pooled analysis of data from the 24-week double-blind treatment phases (DBTPs) of phase 2 and 3 studies evaluated the efficacy of once-monthly erenumab 70 mg in Japanese patients. Patients were categorized into subgroups by monthly migraine days (MMD): LFEM and HFEM/CM. The main efficacy outcomes were change from baseline in MMD, acute migraine-specific medication treatment days (MSMD), and six-item Headache Impact Test (HIT-6™) scores. RESULTS: Patients with migraine (n = 532) were included in the analysis (LFEM, n = 215; HFEM, n = 215; CM, n = 102). Overall, mean age was 44 years, 86.5% were female, and 63.3–88.2% had used or were taking migraine preventive treatment at baseline. Throughout the DBTP, the placebo-adjusted mean change from baseline in MMD, MSMD, and HIT-6 scores with erenumab was similar across LFEM and HFEM/CM subgroups. The proportion of patients achieving at least 50% or 75% reduction from baseline in MMD and MSMD was similar across migraine frequency groups. Reduction in MMD moderately correlated with improvement in HIT-6 scores in the LFEM and HFEM/CM groups. Furthermore, the proportion of patients converting from HFEM/CM to LFEM during the DBTP was higher in the erenumab group than in the placebo. CONCLUSION: In Japanese patients with different migraine frequencies, erenumab treatment resulted in significant improvements in MMD, MSMD, and headache impact. This pooled analysis of data from phase 2 and 3 studies increases confidence that erenumab is efficacious in patients with high MMD, which is associated with increased disability. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40120-023-00538-w.