Safety and effectiveness of diazepam nasal spray in patients with Rett syndrome and seizure clusters: post hoc analyses from a long-term safety study and survey of severity and burden.

INTRODUCTION

Rett syndrome is a neurodevelopmental disorder associated with epilepsy that influences motor/communication skills, behavior, and other systems. Clinical experiences for these patients are not well described.

METHODS

This post hoc analysis consists of a patient subgroup with Rett syndrome enrolled in an open-label, single-arm, safety study. Age- and weight-based doses of diazepam nasal spray (5-20 mg) were administered to patients (aged 6-65 years) for seizure clusters. Treatment-emergent adverse events (TEAEs) were recorded, and days between seizure clusters (SEIzure interVAL [SEIVAL]) from Period 1 (P1; days 1-90) to Period 4 (P4; days 271-360) were calculated. Caregivers completed surveys describing experiences with diazepam nasal spray and Rett syndrome.

RESULTS

Rates of TEAEs (87.5%), serious TEAEs (12.5%), and treatment-related TEAEs (18.8%) in patients with Rett syndrome (n = 16) who received diazepam nasal spray were comparable to the overall pediatric safety population (87.2, 35.9, and 14.1%, respectively; n = 78), as was use of second doses (proxy for effectiveness) (18.4 and 11.4%). Increase in SEIVAL was also similar (P1 = 7.6, P4 = 25.0 days and P1 = 13.0, P4 = 25.9 days). Most (n = 12; 75.0%) remained in the study ≥12 months. All caregivers felt diazepam nasal spray was very/extremely easy to use; 63.6% were able to return to normal activities within an hour of administration. Caregiver perceptions of clinical severity and caregiver affect were stable from baseline to final visits; scores for individuals using diazepam nasal spray were numerically higher.

CONCLUSION

Diazepam nasal spray has safety and effectiveness profiles consistent with the full study population and was easy to use.

CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02721069.