Proof of efficacy trials: seizure types.

For proof of efficacy studies, ideally the seizure types included should also be the most common types of seizures so that an efficacy trial can recruit patients easily and in the shortest possible time frame, provide efficacy data that is valid for a large portion of the epilepsy population, include readily identifiable seizure types that are simple to count, and include seizures that occur frequently enough so that the trial can be short (3 months). Partial seizures are the most common seizure type in an adult population and therefore they represent the first choice for proof of efficacy studies, provided that data in experimental models support efficacy in this seizure type. Because there are already several antiepileptic drugs (AEDs) available which are effective for primary generalized seizure types, and patients with refractory primary generalized seizures are not so plentiful, and including these seizures as primary types to prove efficacy would be time consuming, expensive and therefore not feasible. It is concluded that, whereas proof of concept studies may include other seizure types, the first proof of efficacy studies should be undertaken in patients with frequent (>3/month) partial seizures.