Clinical Trials

Inclusion Criteria: 

• Be properly informed of the nature and risks of the study and give informed consent in writing, prior to entering the study .
• Male or female, 18 to 75 years of age (inclusive).
• BMI < 37 kg/m^2.
• Diagnosis (≥ 2 years) of focal epilepsy according to the International League Against Epilepsy [ILAE] Classification of Epilepsy (2017).
• Prior neuroimaging within the last 10 years and documentation is available.
• Treatment with a stable dose of 1 to 3 allowable current AEDs for at least one month prior to screening, during baseline, and throughout the duration of the study.
• Must be willing to comply with the contraception requirements.
• Males must agree not to donate sperm from the time of the first administration of IMP until 6 months after the last dose of IMP. Females must agree not to donate ova from the time of the first administration of IMP until 6 months after the last dose of IMP.
• Able to keep accurate seizure diaries.
• Able to participate for the full term of the study.

Exclusion Criteria:

• Previously documented EEG which shows any pattern not consistent with focal etiology of seizures.
• History of focal aware non-motor seizures only.
• History of pseudoseizures or psychogenic seizures.
• History of a primary generalized seizure.
• Presence or previous history of Lennox-Gastaut syndrome.
• Seizures secondary to illicit drug or alcohol use, ongoing infection, neoplasia, demyelinating disease, degenerative neurological disease, or central nervous system disease deemed progressive, metabolic illness, or progressive degenerative disease, progressive structural lesion or encephalopathy.
• History of repetitive seizures within the 12-month period preceding study entry where the individual seizures cannot be counted.
• Status epilepticus within the last 12 months prior to enrollment.
• History of neurosurgery for seizures < 1 year prior to enrollment, or radiosurgery < 2 years prior to enrollment.
• Schizophrenia and other psychotic disorders (e.g., schizophreniform disorder, schizoaffective disorder, psychosis not otherwise specified [NOS]), bipolar disorder, and/or obsessive-compulsive disorder, or other serious mental health disorders. Uncontrolled unipolar major depression where changes in pharmacotherapy are needed or anticipated during the study.
• Active suicidal plan/intent in the past 6 months, or a history of suicide attempt in the last 2 years, or more than 1 lifetime suicide attempt.
• History or presence of any significant medical or surgical condition or uncontrolled medical illness at screening including, but not limited to, hematologic, cardiovascular, pulmonary, renal, gastrointestinal, endocrine, hepatic or urogenital systems, or other conditions that would place the patient at increased risk as determined by the Investigator.
• History of cancer within the past 2 years, with the exception of appropriately treated basal cell or squamous cell carcinoma.
• Alanine transferase (ALT; SGPT) or aspartate transferase (AST; SGOT) levels >3 times the upper limit of normal (ULN) at screening or baseline.
• Any clinically significant laboratory abnormalities or clinically significant abnormalities on pre-study physical examination, vital signs or ECG that in the judgment of the Investigator indicates a medical problem that would preclude study participation including but not limited to:
  • History of presence of long QT syndrome; QTcF > 450 msec at baseline; family history of sudden death of unknown cause;
  • History of skin or retinal pigment epithelium abnormalities caused by ezogabine.
• Females who are pregnant, breastfeeding or planning to become pregnant during the first administration of IMP until 6 months after the last dose of IMP.
• History of illicit drug or alcohol abuse within 1 year prior to screening judged by the Investigator to be excessive or compulsive, or currently using drugs of abuse or any prescribed or over-the-counter medication in a manner that the Investigator considers indicative of abuse, dependence or habitual use .
• Exposure to any other investigational drug or device within five half-lives or 30 days prior to screening, whichever is longer.
• Use of vigabatrin in the last 5 years without stable visual fields tested twice over the 12 months after the last dose of vigabatrin (patients stopping vigabatrin more than 5 years prior to screening, must have no vigabatrin-related visual field abnormalities confirmed by examination within the past 6 months - concomitant use of vigabatrin is not allowed).
• If felbamate is used as a concomitant AED, patients must be on felbamate for at least 2 years, with a stable dose for 2 months (or no less than 49 days) prior to Screening. They must not have a history of white blood cell (WBC) count below 2500/μL (2.50 x 10^9/L), platelets below 100,000/mm^3 (100 x 10^9/L), liver function tests (LFTs) above 3 times the upper limit of normal (ULN), or other indication of hepatic or bone marrow dysfunction while receiving felbamate. If patients received felbamate in the past, it must have been discontinued 2 months (or no less than 49 days) prior to Screening.
• Have had multiple drug allergies or a severe drug reaction to an AED(s), including dermatological (e.g., Stevens-Johnson syndrome), hematological, or organ toxicity reactions.
• Current use of a ketogenic diet.
• Any medical condition or personal circumstance that in the opinion of the Investigator exposes the patient to unacceptable risk by participating in the study or prevents adherence to the protocol.
• Employees of Xenon Pharmaceuticals Inc., the contract research organization (CRO), or study site personnel directly affiliated with this study and their immediate family members. Immediate family is defined as a spouse, parent, child or sibling, whether biological or legally adopted.