The study was terminated due to recruitment challenges

The purpose of this study is to investigate the effect on the frequency of tonic-clonic and clonic seizures of clobazam as adjunctive therapy compared to placebo after 16 weeks of treatment in paediatric patients aged ≥1 to ≤16 years with Dravet Syndrome.

Inclusion Criteria:

• Onset of seizures in the first year of life

• History of fever-induced prolonged seizures as determined by the Investigator

• These may include prolonged (approximately 15 minutes or longer) hemi-clonic seizures

• Multiple seizure types which may include:

  • generalised tonic-clonic (required for inclusion)
  • clonic (required for inclusion)
  • myoclonic jerks/seizures
  • history of normal development prior to seizure onset followed by development delay or regression after seizure onset
  • abnormal EEG consistent with Dravet Syndrome 2. The patient has a history of approximately 2 tonic-clonic or clonic seizures in 2 weeks 3. The patient is treated with at least 1 but no more than 3 antiepileptic drugs (AEDs) [Vagal Nerve Stimulator (VNS) and ketogenic diet will not be considered an AED] 4. Patient has at least 2 seizures during the Baseline Period of either 2 or 4 weeks

Exclusion Criteria:

1. The patient is taking stiripentol, verapamil, or felbatol. If patients have taken these drugs in the past, they need to have been off drug for 5 half-lives
2. The patient is taking a sodium channel blocker including, but not limited to, phenytoin, fosphenytoin, carbamazepine, oxcarbamazepine, lamotrigine, lacosamide, and rufinamide. If patients have taken these drugs in the past, they need to have been off drug for 5 half-lives
3. The patient is on cannabidiol, medical marijuana, or any drug that contains cannabinoids
4. The patient has received chronic treatment (≥2 weeks for any indication) with a benzodiazepine within at least 5 half-lives prior to screening. Rescue therapy for prolonged seizures is allowed
5. The patient has received clobazam within 3 months prior to the Screening Visit. If the patient has received clobazam in the past, discontinuation must not have been for adverse events or lack of efficacy

Other protocol-defined inclusion and exclusion criteria may apply.