LOS ANGELES -- Patients with Dravet syndrome may find a reduction in seizures with ZX008 (fenfluramine HCl oral solution) after failing treatment with stiripentol, a drug currently only available in the U.S. via a compassionate-use request. Stiripentol is approved for Dravet syndrome in Canada, Europe, Australia, and Japan.
Post-hoc analysis of a phase III trial of ZX008 showed a 60.8% reduction over placebo in mean monthly convulsive seizures with a 0.8 mg/kg/day dose (P=0.002), reported Elaine C. Wirrell, MD, of the Mayo Clinic in Rochester, Minn. At a lower 0.2-mg/kg/day dose there was a nonsignificant 35.1% reduction over placebo.
Among the 22 patients randomized to receive the 0.8 mg/kg/day dose, 86.4% saw a 25% reduction in major motor seizures over 28 days (OR 23, P=0.001), 72.7% patients saw a 50% reduction (OR 24.7, P=0.006), and 50% saw a 75% reduction (OR 15.8, P=0.036).
There were more treatment-emergent adverse events reported in those receiving the higher dose, the most common of which being decreased appetite -- unsurprising since fenfluramine was once used in Fen-Phen, the weight-loss combination drug that was pulled from the market by the FDA in the 1990s.
In a cardiovascular safety analysis, there were no vases of cardiac valvulopathy reported throughout the 2-week titration or 12-week maintenance phases of the study.
Disclosures
The study on ZX008 was funded by Zogenix, Inc.
Primary Source
American Academy of Neurology
Wirrell EC, et al "ZX008 (fenfluramine HCl oral solution) in Dravet syndrome: effect on convulsive seizure frequency in subjects who failed treatment with stiripentol prior to Study 1, a phase 3 trial" AAN 2018; Abstract P4.469.