Long-Term (12-Month) Safety and Tolerability of STS101 (Dihydroergotamine Nasal Powder) in the Acute Treatment of Migraine: Data from the Phase 3 Open-Label ASCEND Study.

Background and objective: STS101 is an investigational drug-device combination comprising 5.2 mg dihydroergotamine (DHE) powder (6.0 mg DHE mesylate) in a single-use nasal delivery device for the acute treatment of migraine. The primary objective of the ASCEND trial was to assess long-term safety and tolerability of STS101 in the acute treatment of migraine attacks across 12-18 months, with secondary objectives describing efficacy.

Methods: ASCEND was an open-label study of STS101 in adults aged 18-65 years with a ≥ 1 year history of migraine with or without aura, with onset before the age of 50 years and 4-12 migraine attacks/month and < 15 headache days/month in each of the 3 months prior to screening. Exclusion criteria included diagnosis of non-migraine headache, history of cerebrovascular disease, and ≥ 2 cardiovascular risk factors. After establishing eligibility, participants could self-administer STS101 5.2 mg as needed for up to 2 doses within 24 h to treat a single migraine attack and up to 12 doses/month. Safety and tolerability evaluations included physical and nasal examinations, vital signs, laboratory tests, and treatment-emergent adverse event (TEAE) assessments. Participants used an electronic diary to record exploratory efficacy parameters, including intensity of headache pain and associated migraine symptoms (photophobia, phonophobia, and nausea). Participant impression questions were asked at months 3, 6, and 12.

Results: Of the 6610 migraine attacks treated with a total of 8234 STS101 doses in 344 participants, 945/6610 (14.3%) were associated with a TEAE. Events were predominantly mild or moderate in nature and rarely led to premature study discontinuation (15/344 [4.4%] participants). Treatment was associated with rapid onset of freedom from pain (36.6%, 67.1%, and 85.5% of treated attacks 2, 4, and 24 h post-dose, respectively), freedom from most bothersome symptoms (54.3%, 79.6%, and 91.3%), and headache relief (66.5%, 89.1%, and 94.3%). Most participants rated treatment results as good or very good and ease of use as easy or very easy at all time points (months 3, 6, and 12) and indicated they were likely or very likely to use STS101 again.

Conclusions: The repeated long-term, as-needed use of STS101 was well tolerated, demonstrating a favorable safety profile in the acute treatment of migraine attacks in appropriately indicated adults. Exploratory efficacy evaluations indicated beneficial effects, which warrant further evaluation.

Trial registration: ClinicalTrials.gov identification NCT04406649.