Objective: This is the first clinical study in Japanese healthy subjects to assess the safety, tolerability, and pharmacokinetics of lasmiditan, a selective serotonin 5-HT_1F receptor agonist being developed for the acute treatment of migraine.

Methods: This was a Phase 1, randomized, 3-period, subject- and investigator-blind, single-center crossover study. On Day 1 of each period of their assigned treatment sequence, Japanese subjects received single oral doses of lasmiditan 50, 100, 200, and 400 mg or placebo or repeated oral doses (2 single doses administered 2 hours apart) of lasmiditan 200 mg or placebo, and Caucasian subjects received single oral doses of lasmiditan 50, 100, and 200 mg or placebo.

Results: A total of 16 Japanese and 11 Caucasian subjects participated in this study. No deaths, serious adverse events (AEs) , or discontinuations due to AEs occurred. Frequently reported treatment-emergent AEs (TEAEs) were somnolence, dizziness, and hypoesthesia. The frequency of TEAEs in Japanese subjects was higher and dose-dependent compared with Caucasian subjects, in whom no such trend was observed. However, the Japanese AE data was comparable to an integrated summary of TEAEs in 556 non-Japanese healthy subjects with similar doses of lasmiditan administration. Increases in exposure to lasmiditan were observed with increasing dose. The pharmacokinetics of lasmiditan were similar between Japanese and Caucasian subjects, with a mean half-life of approximately 4 hours.

Conclusions: The similar safety and pharmacokinetic profiles of lasmiditan between Japanese and Caucasian subjects support further development of lasmiditan in Japanese populations at the same dose levels studied in Caucasian populations.