Fremanezumab for Chronic Migraine Prevention in Japanese Patients: Subgroup Analysis from Two International Trials.

Purpose: Fremanezumab monoclonal antibody therapy has demonstrated efficacy for chronic migraine (CM) with rapid onset and good tolerability. This subgroup analysis of two clinical trials (Japanese and Korean CM Phase 2b/3 [NCT03303079] and HALO CM Phase 3 [NCT02621931]) aimed to evaluate the efficacy and safety of fremanezumab in Japanese patients. Patients and Methods: Both trials randomly assigned eligible patients at baseline (1:1:1 ratio) to subcutaneous monthly fremanezumab, quarterly fremanezumab, or placebo at 4-week intervals. The primary endpoint was the mean change from baseline in the monthly (28-day) average number of headache days of at least moderate severity during the 12-week period after the first dose of study medication (analyzed by ANCOVA over 12 weeks and MMRM over initial 4 weeks). Secondary endpoints examined other aspects of efficacy, including medication use and disability. Results: A total of 479 and 109 patients were Japanese in the Japanese and Korean CM Phase 2b/3 and HALO CM trials, respectively. Baseline and treatment characteristics were generally similar between treatment groups for both trials. Results of subgroup analyses for the primary endpoint according to ANCOVA demonstrated the superiority of fremanezumab over placebo in Japanese patients (quarterly fremanezumab, p=0.0005; monthly fremanezumab, p=0.0002 in both trials). Results using the MMRM analysis confirmed the rapid onset of action in this population. Results of the secondary endpoints further supported the efficacy of fremanezumab in Japanese patients. Fremanezumab was well tolerated with nasopharyngitis and injection-site reactions representing the most common adverse events in all treatment groups. Conclusion: Despite the limitations of subgroup analyses, these consistent results confirm the efficacy and tolerability of fremanezumab in Japanese patients with CM.