An Open-Label Extension Trial to Assess the Long-Term Safety of ZX008 (Fenfluramine Hydrochloride) Oral Solution as an Adjunctive Therapy for Seizures in Patients with Rare Seizure Disorders Such as Epileptic Encephalopathies Including Dravet Syndrome and Lennox- Gastaut Syndrome

Objectives: The primary objective of the study is: • To assess the long-term safety and tolerability of ZX008 The secondary objectives of the study are: • To assess the effect of ZX008 on the following effectiveness measures: - Investigator assessment of convulsive seizure response (<25%, ≥25%, ≥50%, ≥75%, or 100% [ie, seizure-free] improvement) - Clinical Global Impression – Improvement (CGI-I) rating, as assessed by the investigator - CGI-I rating, as assessed by the parent/caregiver - Symptomatic CGI-I for cognition, behavior, motor abilities, as assessed by the investigator - Symptomatic CGI-I for cognition, behavior, motor abilities, as assessed by the parent/caregiver