A Double-Blind, Placebo-Controlled, Randomized, Single-Center, Cross-Over Study to Investigate the Pharmacodynamic, Pharmacokinetic, Safety, and Tolerability Profiles of Padsevonil in Healthy Study Participants Receiving Either Ethanol or Cannabidiol.

- Participant must be 18 to 55 years of age inclusive, at the time of signing
the informed consent.
- Participants who are overtly healthy as determined by medical evaluation
including medical history, physical examination, laboratory tests, and cardiac
monitoring.
- Participant must have previous experience with alcohol consumption and,
therefore, must be familiar with the effects and able to tolerate social
amounts of alcohol.
- Participant has a body weight of at least 50 kg (males) or 45 kg (females)
and body mass index (BMI) within the range 18 to 30 kg/m2 (inclusive)
- Participants are male or female:
A male participant must agree to use contraception as detailed in the
protocol during the treatment period and for at least 7 days after the last
dose of study treatment and refrain from donating sperm during this period
A female participant is eligible to participate if she is not pregnant,
not breastfeeding, and at least 1 of the following conditions applies:
+Not a woman of childbearing potential (WOCBP) as defined n
the protocol
OR
+A WOCBP who agrees to follow the contraceptive guidance in
the protocol during the Treatment Period and for at least 90 days after the
last dose of study treatment.
-Participant must be capable of giving signed informed consent as described in
Appendix 1 (Section 10.1), which includes compliance with the requirements and
restrictions listed in the informed consent form (ICF).
- Participant must be considered reliable and capable of adhering to the
protocol, according to the judgment of the Investigator, and is capable of
communicating satisfactorily with the Investigator.

-Participant has any medical or psychiatric condition that, in the opinion of
the Investigator, could jeopardize or would compromise the study participant*s
ability to participate in this study, such as 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 the Screening Visit.
- 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
- Participant has a history of chronic alcohol or drug abuse within the
previous 6 months or the presence of drug or alcohol dependency at Screening or
Day -1 or tests positive for alcohol and/or drugs at Screening or Day -1
-Participant has a positive prestudy drug screen (to include at minimum:
amphetamines, barbiturates, cocaine, opiates, cannabinoids and benzodiazepines).
- Participant has a known hypersensitivity to any components of the study
medication or comparative drugs (and/or an investigational device) as stated in
this protocol
-Participant has abnormal blood pressure.
-Participant has a lifetime history of suicide attempt (including an actual
attempt, interrupted attempt, or aborted 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 C-SSRS at
Screening.
- Participant has a history of unexplained syncope or a family history of
sudden death due to long QT syndrome
- Participant has 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
- 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. Specific mediactions listed in section 6.5.1. may be allowed.
- Participant has used hepatic enzyme-inducing drugs (eg, glucocorticoids,
phenobarbital, isoniazid, phenytoin, rifampicin etc.) within 2 months prior to
dosing. In case of uncertainty, the Medical Monitor should be consulted.
- Participant has previously received PSL in this or any other study.
- Participant has participated in another study of an IMP (and/or an
investigational device) within the previous 30 days of Screening or 5
half-lives whichever is longer or is currently participating in another study
of an IMP (and/or an investigational device).
- Participant has alanine transaminase (ALT), aspartate aminotransferase (AST),
or alkaline phosphatase (ALP) >1.0x upper limit of normal (ULN)
- Participant has bilirubin >1.0xULN (isolated bilirubin >1.0xULN is acceptable
if bilirubin is fractionated and direct bilirubin <35%).
- Participant has current or chronic history of liver disease or known hepatic
or biliary abnormalities (with the exception of Gilbert's syndrome or
asymptomatic gallstones)
- Participant has any clinically relevant ECG finding at the Screening Visit or
at Baseline. Study participant has an abnormality in the 12-lead ECG that, in
the opinion of the Investigator, increases the risks associated with
participating in the study. In addition, any study participant with any of the
following findings will be excluded: (a) QT interval corrected for heart rate
using Bazett*s formula (QTcB) or Fridericia*s formula (QTcF) >450ms in
participants in 2 of 3 ECG recordings; (b) other conduction abnormalities
(defined as PR interval *220ms); (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.
- Participant has other clinical laboratory test results outside the local
reference ranges that are considered as clinically significant by the
Investigator. In the case of uncertainty, lab parameters outside the reference
ranges can be retested once. If lab parameters outside the reference range are
considered as clinically insignificant, the study participant may be allowed in
the study, but such inclusions should be agreed with the UCB Study Physician.
- Participant has the presence of hepatitis B surface antigen (HBsAg) at
Screening or within 3 months prior to dosing
- Participant has a positive hepatitis C antibody test result at Screening.
- Participant has a positive human immunodeficiency virus (HIV) antibody test
at screening.
-Participant has made a blood or plasma donation or has had a comparable blood
loss (>450mL) within the last 90 days prior to the Screening Visit. Blood
donation during the study is not permitted.
-Participant has a consumption of more than 600mg of caffeine/day (200mL of
coffee contains approximately 100mg of caffeine, 200mL of black tea
approximately 30mg, and 200mL of cola approximately 20mg).
-Participant smokes more than 5 cigarettes per day (or equivalent) or has done
so within 6 months prior to the Screening Visit. Smoking within 48 hours prior
to CNS assessments is prohibited.
-Participant ingests grapefruit, passion fruit, or pawpaw (as beverage, fruit,
or supplements) within 72 hours before each administration of IMP. If this is
the case at the start of the study, study participants may be rescreened.
-Female participants tests positive for pregnancy, plans to get pregnant during
the participation in the study, or who is breastfeeding.
-Study participant has a diet that deviates notably from the *normal* amounts
of protein, carbohydrate, and fat, as judged by the Investigator.
-Study participant has undergone sudden and/or extreme changes in exercise
levels for 2 weeks prior to Screening Visit.