Introduction: Lasmiditan (COL-144; LY573144) is a novel, highly selective and potent agonist at 5-HTIF receptors that lacks vasoconstrictor activity. Preclinical and early clinical experiments... Show moreIntroduction: Lasmiditan (COL-144; LY573144) is a novel, highly selective and potent agonist at 5-HTIF receptors that lacks vasoconstrictor activity. Preclinical and early clinical experiments predict acute antimigraine efficacy of COL-144 that is mediated through a non-vascular, primarily neural, mechanism. Subjects and methods: In a randomised, multicentre, placebo-controlled, double-blind, group-sequential, adaptive treatment-assignment, proof-of-concept and dose-finding study, we treated 130 subjects in-hospital during a migraine attack. Subjects were allocated to an intravenous dose level of lasmiditan or placebo in small cohorts. The starting dose was 2.5 mg. Subsequent doses were adjusted, up or down, according to the safety and efficacy seen in the preceding cohort. The primary outcome measure was headache response defined as improvement from moderate or severe headache at baseline to mild or no headache at 2 h post-dose. The study was designed to explore the overall dose response relationship but was not powered to differentiate individual doses from placebo, nor to detect effect differences for other migraine symptoms. Results: Forty-two subjects received placebo and 88 received lasmiditan in doses of 2.5-45 mg. Subjects were observed in the clinic for 4 h after treatment and used a diary card to record symptoms and adverse events for up to 24 h. The study was terminated when the 20 mg dose met predefined efficacy stopping rules. Of subjects treated in the 10, 20, 30 and 45 mg lasmiditan dose groups, 54-75% showed a 2 h headache response, compared to 45% in the placebo group (P = 0.0126 for the linear association between response rates and dose levels). Patient global impression at 2 h and lack of need for rescue medication also showed statistically significant linear correlations with dose. Lasmiditan was generally well tolerated. Adverse events were reported by 65% of subjects on lasmiditan and by 43% on placebo and were generally mild. Dizziness, paresthesia and sensations of heaviness (usually limb) were more common on lasmiditan. Conclusions: At intravenous doses of 20 mg and higher, lasmiditan proved effective in the acute treatment of migraine. Further studies to assess the optimal oral dose and full efficacy and tolerability profile are under way. The non-vascular, neural mechanism of action of lasmiditan may offer an alternative means to treat migraine especially in patients who have contra-indications for agents with vasoconstrictor activity. The clinicaltrials.gov identifier for this study is NCT00384774. Show less
