OBJECTIVE: To evaluate safety- and seizure-related outcomes with repeated intermittent use of a novel formulation of midazolam administered as a single-dose nasal spray (MDZ-NS) in the outpatient treatment of patients experiencing seizure clusters (SCs).
METHODS: In this open-label extension trial (ClinicalTrials.gov NCT01529034), patients aged 12 years or older and on a stable regimen of antiepileptic drugs who completed the original phase III, randomized controlled trial were enrolled. Caregivers administered MDZ-NS 5 mg when patients experienced SCs; a second dose could be given if seizures did not terminate within 10 minutes or recurred within 10 minutes-6 hours. Patients were monitored for treatment-emergent adverse events (TEAEs) throughout, and the main seizure-related outcome was treatment success, defined as seizure termination within 10 minutes and no recurrence 10 minutes-6 hours after drug administration.
RESULTS: Of 175 patients enrolled, 161 (92.0%) received one or more MDZ-NS dose, for a total of 1998 SC episodes. Median time spent by patients in the trial was 16.8 months (range = 1-55.7 months). TEAEs were experienced by 40.4% of patients within 2 days of drug administration and 57.1% overall. TEAEs reported by most patients (within 2 days and overall) were nasal discomfort (12.4%) and somnolence (9.3%). One patient each discontinued due to treatment-related nasal discomfort and somnolence. There were no patients with treatment-related respiratory depression, and none with TEAEs indicative of drug abuse or dependence. Treatment success criteria were met in 55% (1108/1998) of SC episodes after administration of a single 5-mg dose and in 80.2% (617/769) with the second dose. Treatment success was consistent over treated episode number.
SIGNIFICANCE: Repeated, intermittent, acute treatment of patients experiencing seizure clusters with midazolam nasal spray in the outpatient setting was well tolerated over an extended period, with maintenance of efficacy suggesting lack of development of tolerance.