The secondary objectives are:~To evaluate the efficacy of carisbamate (YKP509) as adjunctive treatment in reducing the total number of seizures compared with placebo in pediatric and adult subjects diagnosed with Lennox Gastaut Syndrome (LGS)~Assess subject's Quality of Life (QOL)~Evaluate the safety, tolerability of carisbamate in the LGS population~Evaluate steady-state pharmacokinetics of carisbamate in subjects with Lennox Gastaut.
The primary objective is to evaluate the efficacy of carisbamate (YKP509) as adjunctive treatment in reducing the number of drop seizures (tonic, atonic, and tonic-clonic) compared with placebo in pediatric and adult subjects (age 4-55 years) diagnosed with Lennox Gastaut Syndrome (LGS).