Phase III STOP 301 trial of INP 104 meets primary endpoint in acute migraine.- Impel NeuroPharma

Impel NeuroPharma announced positive results from “STOP 301” (Safety and Tolerability of POD-DHE), the Company’s pivotal Phase III, open-label study of the safety and tolerability of INP 104 (dihydroergotamine mesylate) or DHE, administered to the vascular rich upper nasal space via Impel’s proprietary POD technology, for the treatment of acute migraine. The study, which treated over 5,650 migraine attacks, evaluated self-administered, intermittent use of INP 104 for up to 52-weeks, and also collected in a diary exploratory efficacy data of INP 104 as assessed by patient reported change from baseline in migraine measures during the course of the study.

Results showed the STOP-301 study met its primary objectives, with no new safety signals or concerning trends in nasal safety findings observed for INP104 following delivery of DHE to the upper nasal space. DHE is a molecule long relied upon for its high response rate and sustained efficacy. Its use has been limited in part by its availability only as an invasive injectable or in other delivery forms with high dosing variability. In the study, the majority of treatment-related adverse events for the 24-week Full Safety Set (FSS) (n=354) were mild and transient in nature. The most frequently reported adverse events (at least 5%) during the entire 24-week period were nasal congestion (15.0%), nausea (6.8%), nasal discomfort (5.1%) and unpleasant taste (5.1%). The majority of patients (74% and 90%) completed the 24- and 52-week phases of the study, respectively. No drug-related serious adverse events (SAEs) were observed over the entire 52-week study.

In the study, INP 104 delivered 1.45 mg of DHE, less than 72.5% of the currently approved dose (2.0 mg). Optimal dosing is critical so that patients may stand to benefit from the established efficacy profile of DHE, without the potentially triggering undesired side effects that can be experienced with delivering higher doses of drug to the lower nasal space. Per the approved product label for Migranal, the FDA currently limits the maximum dose of DHE to 4.0 mg a week. Exploratory efficacy data in the FSS (n=354) observed that 66.3% of patients achieved pain relief and 38% of patients achieved pain freedom at two hours following their first dose of INP 104. In the Primary Safety Set (PSS) (n=185), 33.1% of patients who took an average of two or more treatments with INP 104 per the 28-day period during the 24-week treatment phase, achieved pain freedom at two hours.