Open-label Study of Cenobamate Monotherapy in Adult Subjects With Newly Diagnosed or Recurrent Partial-Onset Epilepsy

Inclusion Criteria:

1. Be considered reliable and willing to be available for the study period and are ableto record seizures and report adverse events (AEs) himself/herself or have acaregiver who can record seizures and report AEs for them.

2. Male or female subjects 18-74 years of age with a diagnosis of partial-onsetseizures (POS) according to the 2017 ILAE Classification of Epileptic Seizures.Diagnosis will be established by clinical history and an electroencephalogram (EEG)consistent with POS. Subjects with a normal EEG could be included provided they metthe other diagnostic criteria according to clinical history.

3. Subjects who are newly diagnosed or have recurrent epilepsy and have experienced:

4. At least 2 unprovoked seizures (at least >24 hours apart) within the 1 yearprior to Day 1 of the Treatment Period, of which, at least 1 unprovoked seizure (but below 20 seizures) occurred in the 12 weeks prior to Day 1 of theTreatment Period.OR

5. 1 unprovoked seizure within the 12 weeks prior to Day 1 of the Treatment Periodwith concomitant information to support an increased risk (>60%) of a secondseizure. In the absence of clear information about recurrence risk, or evenknowledge of such information, the default definition of epilepsy originates atthe second unprovoked seizure. Subjects who are newly diagnosed and have been prescribed a low dose of 1 ASM for ≤12 weeks can be included if the other ASM can be safely down-titrated/discontinuedper Investigator discretion within 6 weeks after the 1st dose of cenobamate. Forsubjects with recurrent epilepsy, they must have relapsed at least 6 months afterthe end of the last ASM treatment but can have been prescribed a low dose of 1 ASMfor ≤12 weeks if the other ASM can be safely down-titrated/discontinued perInvestigator discretion within 6 weeks after the 1st dose of cenobamate.

6. Female subjects are either not of childbearing potential, defined as premenarchal,postmenopausal for at least 1 year or surgically sterile (bilateral tubal ligation,bilateral oophorectomy, or hysterectomy), if of childbearing potential, must complywith an acceptable method of birth control during the study, for at least 4 weeksprior to study entry and for 2 weeks after last dose of study drug.

7. Subject and/or caregiver(s)/legal representative must be willing and able to giveinformed assent/consent for participation in the study.

8. Subject and their caregiver must be willing and able (in the investigator's opinion)to comply with all study requirements.

Exclusion Criteria:

1. Subjects who have only simple partial-onset seizures (focal aware seizures) withoutmotor signs.

2. Subjects who have seizure clusters where individual seizures cannot be counted.

3. Subjects who present with or have a history of Lennox-Gastaut syndrome.

4. Subjects who have a history of status epilepticus that required hospitalizationwithin 1 year prior to Day 1 of the Treatment Period.

5. Subjects who have a history of psychogenic non-epileptic seizures within 2 yearsprior to Day 1 of the Treatment Period.

6. Subjects who have a history of active suicidal ideation within the last 6 months orsuicide attempt within 2 years prior to Day 1 of Treatment Period.

7. Evidence of clinically significant disease (eg, cardiac, respiratory,gastrointestinal, psychiatric, other neurological) that in the opinion of theinvestigator(s) could affect the subject's safety or interfere with the studyassessments.

8. History of Familial Short QT syndrome or prior subject diagnosis of Short QTsyndrome.

9. Evidence of clinically significant active renal or hepatic disease.

10. Subjects taking a strong CYP3A inducer such as phenytoin, phenobarbital,carbamazepine, or rifampin within 12 weeks prior to the Pretreatment Period unlessemergency care was needed due to the subject experiencing status epilepticus,uncontrolled seizures, or clusters of seizures.

11. Subjects who are taking more than one of the following centrally acting drugs:antipsychotic, antidepressant, or anxiolytic. The dose should be stable for the 12weeks prior to the Pretreatment Period.

12. Subjects who have a history of any type of surgery for brain or central nervoussystem within 1 year prior to the Pretreatment Period.

13. Subjects who have a history of receiving any ASM (including ASM used as rescuetreatment and ASMs used for indications other than epilepsy) for more than 12 weeksin total within 6 months prior to Day 1 of the Treatment Period.

14. Subjects who have used intermittent rescue medicine on 2 or more occasions within 12weeks before the Pretreatment Period (1 to 2 doses over a 24-hour period consideredone-time rescue).

15. Subjects who have a history of receiving any ASM polytherapy (> 2 ASMs takenconcurrently) during a previous episode of epilepsy.

16. Previous exposure to cenobamate or sensitivity/allergy to components of the oraltablets.

17. Subjects who have a history of drug or alcohol dependency or abuse within the last 2years before the Pretreatment Period.

18. Subjects who have had multiple drug allergies or a severe drug reaction, includingdermatological (eg, DRESS syndrome, Stevens-Johnson syndrome), hematological, ororgan toxicity reactions.

19. Females who are breastfeeding or pregnant or planning to get pregnant in thePretreatment Period or during the conduct of the study.

20. Subjects who have participated in a study involving administration of aninvestigational drug or device within 4 weeks before Visit 1, or withinapproximately 5 half-lives of the previous investigational compound, whichever islonger.

21. Subjects with dementia.

22. Subjects who have seizures due to a progressive CNS condition.