A Study to Test the Safety and Tolerability of Brivaracetam in Children and Adolescents With Seizures

Inclusion Criteria: Inclusion criteria for long-term follow-up (LTFU) study participants only * Study participants ≥ 1 month of age with a confirmed diagnosis of epilepsy who participated in core study N01266 \[NCT01364597\] and/or N01349 \[NCT03325439\] Inclusion criteria for directly enrolled (DE) study participants in Japan only * Study participant is ≥ 4 years to \< 16 years of age * Study participant has presence of an electroencephalogram (EEG) reading compatible with the diagnosis of focal epilepsy within the last 10 years * Study participant has uncontrolled partial-onset seizure (POS) after an adequate course of treatment with at least 1 antiepileptic drug (AED) * Study participant had at least 1 POS during the 4-week Screening Period Exclusion Criteria: Exclusion criteria for all study participants * Severe medical, neurological, or psychiatric disorders or laboratory values, which may have an impact on the safety of the study participant * Study participant is currently participating in another study of an investigational medication (or a medical device) other than brivaracetam (BRV). Exclusion criteria for long-term follow-up (LTFU) study participants only \- Study participant ≥ 6 years of age has a lifetime history of suicide attempt or has suicidal ideation in the past 6 months as indicated on the Columbia Suicide Severity Rating Scale (C-SSRS) Exclusion criteria for directly enrolled (DE) study participants in Japan only * Study participant has a history of primary generalized epilepsy, psychogenic non-epileptic seizures, or febrile seizures * Study participant has a history of status epilepticus in the 30 days prior to the Screening Visit (ScrV) or during the Screening Period * Study participant has any clinically significant illness * Study participant has clinically significant laboratory abnormality that may increase the risk associated with study participation or may interfere with the interpretation of study results * Study participant has a clinically significant ECG abnormality * Study participant had major surgery within 6 months prior to the ScrV