This clinical trial is focused on studying Lennox-Gastaut syndrome (LGS), a type of epilepsy that causes multiple types of seizures and developmental delays in children and adults. The study is testing a treatment called Carisbamate, also known by its code name YKP509, which is taken as an oral suspension. The purpose of the study is to evaluate how effective and safe Carisbamate is when used alongside other treatments to reduce the number of specific seizures, such as tonic, atonic, and tonic-clonic seizures, in people with LGS.
Participants in the study will be randomly assigned to receive either Carisbamate or a placebo, which looks like the treatment but does not contain the active medicine. The study will be conducted in a double-blind manner, meaning neither the participants nor the researchers will know who is receiving the actual treatment or the placebo. This helps ensure that the results are unbiased. The study will include both children and adults aged 4 to 55 years who have been diagnosed with LGS. Participants will continue their current anti-seizure medications while taking part in the study.
The trial will last for a period of time during which participants will be monitored for changes in the frequency of their seizures. There is also an optional open-label extension, where all participants can receive Carisbamate after the initial study period. The main goal is to see if Carisbamate can significantly reduce the number of drop seizures, which are seizures that can lead to falls or injuries. Participants and their caregivers will be asked to keep a diary of seizures to help track any changes during the study.



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