Abstract Background There have been very few real-world studies reported in the literature solely focusing on fremanezumab in Asia. This study aimed to evaluate the efficacy and safety of fremanezumab in a real-world setting in Japan. Method This single-centered, observational, retrospective study examined patients with migraines who received four doses of fremanezumab between December 2021 and August 2022 at Keio University Hospital. We assessed the changes in monthly migraine days, responder rates, and migraine-associated symptoms, as well as injection site reactions and adverse events. Result Twenty-nine patients were enrolled, wherein 79.3% were women. Compared with those at baseline, the monthly migraine days decreased by 5.9 days at 4 months. The 50% responder rate was 55.2% at 4 months. A total of 57.9%, 47.8%, and 65.0% of patients showed improvement in the severity of photophobia, phonophobia, and nausea/vomiting, respectively. Moreover, injection site reactions were the most common adverse events (55.2%). Conclusion Fremanezumab is effective and safe for migraine prevention in Japan. Fremanezumab also improved migraine-associated symptoms in half of the patients.
