Adjunctive treatment of persons with Dravet syndrom with the investigational compound, low-dose fenfluramine hydrochloride (ZX008; Zogenix, Emeryville, CA), has been shown to have a statistically significant effect on convulsive seizure reduction versus placebo in a phase 3 pivotal trial. Results are consistent with what was seen and reported in the first pivotal phase 3 study that demonstrated that low-dose fenfluramine hydrochloride (0.5 mg/kg/day up to a maximum 20 mg/day) is superior to placebo when added to a stiripentol regimen.
Patients taking fenfluramine achieved a 54.7% greater reduction in mean monthly convulsive seizures compared to those treated with placebo (P <0.001) and the median reduction in monthly convulsive seizure frequency was 62.7% in those treated with fenfluramine versus 1.2% in patients treated with placebo. Treatment with fenfluramine also provided statistically significant improvement versus placebo longest seizure-free interval.
Low-dose fenfluramine was generally well-tolerated within the known safety profile of fenfluramine. No patient exhibited cardiac valvulopathy or pulmonary hypertension.
“These impressive study results show the significant impact the addition of ZX008 made in reducing the burden of convulsive seizures for patients who are not adequately controlled using stiripentol, the standard of care for the treatment of Dravet syndrome in Europe,” said Professor Rima Nabbout, MD, PhD, Department of Pediatric Neurology, Reference Center for Rare Epilepsies, Necker Enfants Malades Hospital, and Principal Investigator of Study 1504. “If approved, ZX008 has the potential to be a transformative treatment for Dravet syndrome, a rare and serious form of epilepsy with few available treatment options.”