Brivaracetam as add-on Treatment of Unverricht-Lundborg Disease in Adolescents and Adults

Inclusion Criteria: * Subjects with diagnosed Unverricht-Lundborg disease (ULD) ascertained by appropriate genetic testing for a homozygous or compound heterozygous mutation in the Cystatin B (CSTB) gene * Subjects with moderate to severe myoclonus documented by an Action Myoclonus sum score of ≥ 30 (evaluation by investigator) * Subjects currently being or having been treated with clonazepam up to the maximum recommended daily dose of 20 mg or up to their individual optimal dose as assessed by the investigator * Subjects currently being or having been treated with valproate up to the maximum recommended daily dose 60 mg/kg or serum levels of 100 mcg/ml or up to their individual optimal dose as specified by the investigator Exclusion Criteria: * Subjects currently on felbamate or having been on felbamate within less than 18 months prior to Visit 1 * Subjects currently treated with phenytoin or having been on phenytoin in the last month prior to Visit 1 * Subjects currently on vigabatrine. Subjects having been on vigabatrine if no visual fields examination report available including standard static (Humphrey or Octopus) or cinetic perimetry (Goldman) * Subject taking any drug with possible central nervous system (CNS) effects * Subjects taking any drug that may significantly influence the metabolism of BRV (CYP2C or CYP3A potent inducers/inhibitors) * Known clinically significant acute or chronic illness or illness which may impair reliable participation in the trial, necessitate the use of medication not allowed by protocol or represent a safety risk in the Investigator's opinion * Subjects with history of severe adverse hematological reaction to any drug * Impaired hepatic function: ALAT/SGPT, ASAT/SGOT, alkaline phosphatase, GGT value of more than three times the upper limit of the reference range * History of suicide attempt during the last 5 years * Subject with suicidal ideations within the last year or at risk of suicide attempt unless cleared by written confirmation from a psychiatrist and approved by the UCB physician * Ongoing psychiatric disorder other than mild controlled disorder