Paracelsus Medizinische Privatuniversität (PMU)

Research & Innovation
Publications

Long-term safety and effectiveness of fenfluramine in children and adults with Dravet syndrome

#2025
#EPILEPSIA

PMU Author
Milka Pringsheim

All Authors
Ingrid E. Scheffer, Rima Nabbout, Lieven Lagae, Orrin Devinsky, Stephane Auvin, Elizabeth A. Thiele, Elaine C. Wirrell, Tilman Polster, Nicola Specchio, Milka Pringsheim, Katsumi Imai, Michael D. Lock, Melanie Langlois, Rebecca Zhang Roper, Amelie Lothe, Joseph Sullivan

Journal association
EPILEPSIA

Abstract

Objective We analyzed the long-term safety and effectiveness of fenfluramine (FFA) in patients with Dravet syndrome (DS) in an open-label extension (OLE) study after participating in randomized controlled trials (RCTs) or commencing FFA de novo as adults. Methods Patients with DS who participated in one of three RCTs or were 19 to 35 years of age and started FFA de novo were included. Key endpoints were: incidence of treatment-emergent adverse events (TEAEs) in the safety population, and median percentage change in monthly convulsive seizure frequency (MCSF) from the RCT baseline to end of study (EOS) in the modified intent-to-treat (mITT) population. Post hoc analyses compared effectiveness in patients on concomitant stiripentol (STP) vs those not taking STP, and assessed safety (TEAEs) and effectiveness (Clinical Global Impression-Improvement [CGI-I] scale ratings) in patients enrolled as adults. Results A total of 374 patients, including 45 adults, received >= 1 FFA dose. Median FFA exposure was 824 days (range, 7-1280). TEAEs occurring in >= 10% of patients were pyrexia, nasopharyngitis, decreased appetite, seizure, decreased blood glucose, diarrhea, abnormal echocardiography (only physiologic regurgitation), upper respiratory tract infection, influenza, vomiting, and ear infection; no valvular heart disease or pulmonary arterial hypertension was observed over the OLE. In the mITT population (n = 324), median percentage change in MCSF from baseline to EOS was -66.8% (p < .001). The post hoc analyses of MCSF change from baseline to EOS in patients on concomitant STP (n = 75) was -36.2% vs -71.6% in those not on concomitant STP (n = 234) (p < .0001). In adult patients, 29 of 41 (70.7%) and 29 of 42 patients (69.1%) demonstrated clinically meaningful improvement on CGI-I at last visit as rated by caregivers and investigators, respectively. Significance Our OLE study of FFA in patients with DS confirmed previous positive findings and extended the exposure up to 3.5 years. No new or unexpected safety signals were observed and FFA demonstrated sustained and clinically meaningful reduction in MCSF.

Keywords

EPILEPSY, seizure, Anti-seizure medication