Stiripentol

Greg L. Plosker

Stiripentol is an anticonvulsant used as adjunctive therapy with valproate and clobazam in the management of patients with severe myoclonic epilepsy of infancy (SMEI; Dravet syndrome), a rare form of epilepsy that develops in the first year of life and is subsequently associated with significant morbidity and mortality. Results of a randomized, double-blind trial, in which patients (≥3 years of age) whose SMEI was inadequately controlled with valproate and clobazam received adjunctive therapy with stiripentol or placebo for 2 months, showed a significantly higher response rate in the stiripentol group compared with the placebo group (71 % vs. 5 %; p < 0.0001; primary endpoint). Responders were defined as those patients who experienced a ≥50 % reduction in clonic or tonic-clonic seizure frequency during the second month of the double-blind period compared with baseline. Almost half of the stiripentol recipients were seizure free during this period compared with none in the placebo group. Stiripentol was also statistically superior to placebo for secondary efficacy outcomes in the randomized controlled trial, which included the median number of seizures during the second month of the double-blind period and the mean percentage change from baseline in seizure frequency. These results are supported by efficacy data from other studies in patients with SMEI treated with stiripentol as adjunctive therapy, including a long-term retrospective analysis, prospectively conducted open-label studies and a meta-analysis. Drowsiness, loss of appetite and weight loss are the most frequently reported adverse events with stiripentol, and the drug inhibits various cytochrome P450 isoenzymes, potentially leading to clinically significant drug interactions. Stiripentol is an important addition to the limited treatment options available for the management of patients with SMEI.