Study to Evaluate the Safety and Efficacy of USL261 (Intranasal Midazolam) in Patients With Seizure Clusters

The purpose of this study is to examine the safety and effectiveness of USL261 for the outpatient treatment of seizure clusters.

Qualifying participants underwent an in-clinic administration (Test Dose Phase \[TDP\]) of two doses of USL261 (intranasal midazolam 5 mg), separated by 10 minutes, in the absence of seizures. Eligible participants were then randomized to USL261 versus Placebo in an outpatient Comparative Phase (CP). When the participant had a qualifying seizure cluster episode, as described in an individualized patient management plan, the participant's caregiver administered the double-blind dose. An open-label USL261 dose could be administered after 10 minutes and up to 6 hours after the double-blind dose, if the participant had persistent or recurrent seizures. Initial participants could not proceed to CP until an independent data safety monitoring board (DSMB) reviewed safety data from at least the first 25 participants in TDP; the DSMB performed additional safety reviews at pre-set intervals based on enrollment.