Introduction: Dravet syndrome (DS), a prototypic developmental and genetic epileptic encephalopathy (DEE), is characterized by an early onset of treatment-refractory seizures, together with impairments in motor control, behavior, and cognition. Even with multiple conventional anti-epileptic drugs, seizures remain poorly controlled, and there has been a considerable unmet need for effective and tolerable treatments.
Areas covered: This targeted literature review aims to highlight recent changes to the therapeutic landscape for DS by summarizing the most up-to-date, evidence-based research, including pivotal data from the clinical development of stiripentol, cannabidiol, and fenfluramine, which are important milestones for DS treatment, together with the latest findings of other pharmacotherapies in development. In phase III, double-blind, placebo-controlled randomized controlled trials stiripentol, cannabidiol, and fenfluramine have shown clinically relevant reductions in convulsive seizure frequency, and are generally well tolerated. Stiripentol was associated with responder rates (greater than 50% reduction in convulsive seizure frequency) of 67%-71%, when added to valproic acid and clobazam; cannabidiol was associated with responder rates of 43%-49% (48%-63% in conjunction with clobazam), and fenfluramine of 54%-68% across studies. Therapies in development include soticlestat, ataluren, verapamil, and clemizole, with strategies to treat the underlying cause of DS, including gene therapy and antisense oligonucleotides beginning to emerge from preclinical studies.
Expert opinion: Despite the challenges of drug development in rare diseases, this is an exciting time for the treatment of DS, with the promise of new efficacious and well-tolerated therapies, which may pave the way for treatment advances in other DEEs.
Keywords: Cannabidiol; Dravet syndrome; epilepsy; epileptic encephalopathy; fenfluramine; rare diseases; stiripentol.