Follow-up to low-dose fenfluramine for Sunflower syndrome: A non-randomized controlled trial

This study reports on the long-term results for an initial cohort of patients with Sunflower syndrome who enrolled in an open-label study of low-dose fenfluramine as well as the short-term results of a second cohort.

We conducted a single-center, open-label study at the Massachusetts General Hospital. We analyzed the effect of fenfluramine on handwaving seizure frequency at monthly intervals during a 4-month core study period for the second patient cohort, and we evaluated the long-term (>2 years) effect of fenfluramine for the initial patient cohort.

Eight of the 10 patients from the second cohort provided analyzable seizure data. These patients experienced a 33% median reduction in seizure frequency during the core study, as compared to the previously reported 79% for the initial cohort (n = 9). Of the seven patients from the first cohort who remain on fenfluramine in the extension study, five continue to experience benefit. Fenfluramine was overall well tolerated with minimal side effects, reduced appetite and fatigue being the primary adverse events, and no evidence of cardiac valvulopathy or pulmonary hypertension.

This study suggests fenfluramine can be an effective, durable, and well-tolerated antiseizure medication option for patients with Sunflower syndrome.