Safety, tolerability, and pharmacokinetics of a single orally inhaled dose of PUR3100, a dry powder formulation of dihydroergotamine versus intravenous dihydroergotamine: A Phase 1 randomized, double‐blind study in healthy adults

Background Intravenous dihydroergotamine (DHE) has well‐established efficacy for the acute treatment of migraine, but its use is limited by the need for in‐hospital administration and the nausea/vomiting associated with a high maximum plasma concentration (Cmax). Inhalation is an alternative to intravenous dosing. The surface area of the lung allows for rapid absorption of a self‐administered dose. Objective This study evaluated the safety, tolerability, and systemic pharmacokinetics (PK) of a dry powder formulation (PUR3100) DHE when delivered via inhalation compared to intravenous delivery. Methods In this double‐blind, double‐dummy Phase 1 study, healthy volunteers (N = 26) were randomized (1:1:1:1) to one of four groups: orally inhaled placebo plus intravenous DHE 1.0 mg or orally inhaled PUR3100 (0.5, 1.0, or 1.5 mg) plus intravenous placebo. Blood samples were drawn pre‐dose and at time points post‐dose over 48 h. Standard PK and safety parameters were assessed and values for Cmax and area under plasma concentration time curve (AUC) were used to assess comparative exposures of PUR3100 versus intravenous DHE. Results All doses of PUR3100 were associated with a lower incidence of nausea (21% vs. 86%), vomiting (0% vs. 29%), and headache (16% vs. 57%) compared to intravenous DHE. The PK profile of PUR3100 versus intravenous DHE was characterized by a similar mean time to Cmax (5 vs. 5.5 min), with reduced AUC0–2h (1120–4320 vs. 6340), and a lower Cmax (3620–14,400 vs. 45,000). Compared to intravenous DHE 1.0 mg, the highest nominal PUR3100 dose (1.5 mg), which delivers a fine‐particle dose of approximately 0.9 mg to the lungs, had a geometric mean ratio percentage (90% confidence interval [CI]) for Cmax of 32% [17.2, 59.6] and AUC0–inf of 93% (62.9, 138.5), the latter of which was not significantly different. Conclusions Inhaled PUR3100 is associated with rapid systemic PK within the therapeutic window and an improved safety profile relative to intravenous DHE. Plain Language Summary Intravenous dihydroergotamine (DHE) works for the acute treatment of migraine; however, it must be given in a hospital or clinic and has side‐effects including nausea and vomiting. A dry powder formulation of DHE (PUR3100) delivered by oral inhalation had fewer side‐effects than intravenous DHE in healthy volunteers. The pharmacokinetics (the amount of the study drug in blood) showed that inhaled PUR3100 was associated with rapid absorption of DHE into the blood within the