The traditional antiepileptic drug market is highly genericized, and there are limited branded AEDs left without generic equivalents. Additionally, though these newer branded AEDs differentiate themselves from older ones, there are still unmet needs in this market to be addressed, including refractory epilepsy and rare specific epilepsies. 

The partial-onset seizure market represents the largest market in the epilepsy disease space; however, it is highly saturated with an extensive repertoire of anticonvulsants available for prescription. Primary drugs in this patient segment are the broad-label leaders Keppra/Keppra XR, Lamictal/Lamictal XR and Vimpat, as they are simple to use and safe. GSK has managed to slow the ensuing generic erosion of Lamictal/Lamictal XR, but UCB has not been so successful with Keppra/Keppra XR, and now only sees significant sales in Japan.