A Multicenter, Randomized, Double-blind, Parallel Group, Placebo-controlled Trial of Two Fixed Doses of ZX008 (Fenfluramine Hydrochloride) Oral Solution as an Adjunctive Therapy in Children and Young Adults With Dravet Syndrome

Study 1 and Study 3 are the prospective, merged analyses of 2 identical double-blind,
placebo-controlled studies, ZX008-1501 and ZX008-1502, to assess the efficacy, safety, and
pharmacokinetics of ZX008 when used as adjunctive therapy in pediatric and young adult
subjects with Dravet syndrome. Study 1501 and Study 1502 were conducted in parallel; Study
1501 was conducted at approximately 30 study sites in North America; Study 1502 was conducted
at approximately 30 study sites in Europe, Asia and Australia. Upon completion of the
Baseline Period after initial Screening and Baseline charting of seizure frequency, subjects
who qualified for the studies were randomized (1:1:1) in a double-blind manner to receive
either 1 of 2 doses of ZX008 (0.2 mg/kg/day or 0.8 mg/kg/day; maximum dose: 30 mg/day) or
placebo. Randomization was stratified by age group (< 6 years, ≥6 to 18 years) to achieve
balance across treatment arms, with the target of 25% of subjects in each age group. All
subjects were titrated to their randomized dose over a 14-day Titration Period. Following
titration, subjects continued treatment at their randomly assigned dose over a 12-week
Maintenance Period. Subjects exiting the study underwent a 2-week taper, unless they enrolled
in a follow-on study. Subjects were followed for post-study safety monitoring.