A randomized, open-label, 5-period crossover study evaluating the pharmacokinetics and safety of a single dose of intranasal dihydroergotamine (DHE) powder (STS101), intramuscular DHE mesylate, and liquid nasal spray DHE in healthy adults

Objective: To compare the safety and pharmacokinetics (PK) of dihydroergotamine (DHE) after administration of intranasal DHE powder (STS101), liquid nasal spray (LNS) DHE mesylate, and intramuscular (IM) DHE mesylate injection in healthy participants.

Background: DHE is an effective acute migraine treatment; however, self-administration difficulties have prevented its broader role in the management of migraine.

Methods: This randomized, active-controlled, five-period crossover study was conducted over 5 weeks separated by 1-week washout periods. Three STS101 dosage strengths (5.2, 7.0, 8.6 mg), and one dose each of LNS DHE 2.0 mg, and IM DHE 1.0 mg, were administered to 36 healthy participants. Liquid chromatography, tandem mass spectrometry was used to determine DHE (including its 8'OH-DHE metabolite) plasma levels and to calculate PK parameters (C_max , T_max , AUC_0-2h , AUC_0-last , AUC_0-inf , and t_1/2 ). Safety was evaluated by monitoring adverse events (AEs), vital signs, electrocardiograms, nasal examinations, and laboratory parameters.

Results: Thirty-six participants (mean age 36 years; 19% Hispanic Black and 81% Hispanic White) were enrolled. DHE plasma concentrations rose rapidly after STS101 5.2, 7.0, and 8.6 mg and IM DHE injection, with mean concentrations greater than 2000 pg/mL for all STS101 dose strengths at 20 min. All STS101 dose strengths showed approximately 3-fold higher C_max , AUC_0-2h , and AUC_0-inf , than the LNS DHE. The mean AUC_0-inf of STS101 7.0 and 8.6 mg were comparable to IM DHE (12,600 and 13,200 vs. 13,400 h × pg/mL). All STS101 dose strengths showed substantially lower variability (CV%) compared to LNS DHE for C_max (35%-41% vs. 87%), and AUC_0-inf (37%-46% vs. 65%). STS101 was well tolerated, and all treatment-emergent AEs were mild and transient.

Conclusion: STS101 showed rapid absorption and was well tolerated with mild and transient treatment-emergent AEs. Achieving effective DHE plasma concentrations within 10 min, STS101 displayed a favorable PK profile relative to the LNS with higher C_max , AUC_0-2h , and AUC_0inf , and with greater response consistency. The AUC_0-inf was comparable to IM DHE.