Significant improvements in SEIzure interVAL (time between seizure clusters) across time in patients treated with diazepam nasal spray as intermittent rescue therapy for seizure clusters

OBJECTIVE: Intermittent rescue therapy may be used for seizure clusters, which are clinical emergencies that may persist ≥24 h and increase risk of status epilepticus, emergency room visits, and reduced quality of life for patients with epilepsy. Beyond effectiveness for aborting seizure clusters, no data exist on how intermittent rescue therapy may impact the long‐term natural course of seizure clusters. This novel analysis explores SEIzure interVAL (SEIVAL; time between seizure clusters) in patients from a long‐term safety study of diazepam nasal spray (Valtoco) to assess SEIVAL changes with intermittent rescue therapy across time. METHODS: Patients were aged 6–65 years. Age‐ and weight‐based doses of diazepam nasal spray were administered during a 12‐month treatment period with an optional follow‐up period. SEIVAL was evaluated in patients receiving two or more doses of diazepam nasal spray using 90‐day periods. RESULTS: Of 163 treated patients, 151 had one or more SEIVALs. One hundred twenty had SEIVALs in Period 1 and one or more other periods. An increase in SEIVAL was noted from Period 1 compared with all subsequent periods (p ≤ .001). A consistent cohort (n = 76) had one or more SEIVALs in each of Periods 1–4 (360 days); mean SEIVALs increased significantly (p < .01) from 12.2 days (Period 1) to 25.7 days (Period 4). Similar SEIVAL patterns occurred when repeat doses within a seizure cluster were eliminated and irrespective of age group, treatment duration, and change to concomitant medications. In adults, Quality of Life in Epilepsy scores were maintained with increased SEIVALs. SIGNIFICANCE: Across 12 months, increases in SEIVAL were demonstrated in patients using diazepam nasal spray for seizure cluster treatment in a phase 3 safety study. Increased time between seizure clusters may reflect a previously unrecognized beneficial effect of intermittent rescue therapy. These results generate a range of biological and behavioral hypotheses and warrant exploration of the impact of intermittent rescue therapy.