A Study to Test the Safety and Tolerability of Single and Multiple Doses of Padsevonil in Adult and Elderly Study Participants

Inclusion Criteria

• Study participants in the adult cohort must be ≥18 to 64 years of age at the time of signing the informed consent form (ICF)
• Study participants in the elderly cohort must be ≥65 years of age at the time of signing the ICF
• Study participants who are overtly healthy as determined by medical evaluation, including medical history, physical examination, laboratory tests, and cardiac monitoring. In addition, elderly study participants must be considered to be in general good physical and mental health
• Study participants must have a body weight of at least 50 kg for males and 45 kg for females, and a body mass index within the range of 18 to 32 kg/m2 (inclusive)

Exclusion Criteria

• Study participant has a current or past psychiatric condition that, in the opinion of the Investigator, could compromise the study participant's safety or ability to participate in this study, or a history of schizophrenia or other psychotic disorder, bipolar disorder, or severe unipolar depression. The presence of potential psychiatric exclusion criteria will be determined based on the psychiatric history collected at Screening
• Study participant has history or presence of cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrinological, hematological, or neurological disorders capable of significantly altering the absorption, metabolism, or elimination of drugs; constituting a risk when taking the study intervention; or interfering with the interpretation of data
• Study participant has a known hypersensitivity to any components of the study medication as stated in this protocol
• Subject has a history of unexplained syncope or a family history of sudden death due to long QT syndrome
• Study participant has abnormal blood pressure
• Study participant has had lymphoma, leukemia, or any malignancy within the past 5 years, except for basal cell or squamous epithelial carcinomas of the skin that have been resected with no evidence of metastatic disease for 3 years
• Study participant has a lifetime history of suicide attempt, or has had suicidal ideation in the past 6 months as indicated by a positive response ("Yes") to either Question 4 or Question 5 of the "Screening/Baseline" version of the Columbia-Suicide Severity Rating Scale (C-SSRS) at Screening
• Study participant has past or intended use of over-the-counter or prescription medication, including herbal medications within 2 weeks or 5 half-lives prior to dosing
• The study participant has used hepatic enzyme-inducing drugs within 2 months prior to dosing
• Study participant has previously received padsevonil (PSL) in this or another study
• Study participant has alanine aminotransferase (ALT), aspartate aminotransferase (AST), or alkaline phosphatase (ALP) >1.0x upper limit of normal (ULN)
• Study participant has bilirubin >1.0xULN (isolated bilirubin >1.0xULN is acceptable if bilirubin is fractionated and direct bilirubin 450 ms in study participants in 2 of 3 ECG recordings; (b) other conduction abnormalities (defined as PR interval ≥220 ms); (c) irregular rhythms other than sinus arrhythmia or occasional, rare supraventricular or rare ventricular ectopic beats. In case of an out of range result, 1 repeat will be allowed. If out of range again, the study participant cannot be included