Double-blind, Randomized Trial of PRAX-628 in Adults With Focal Seizures to Evaluate Efficacy and Safety (POWER1)

Inclusion Criteria:

1. A diagnosis of focal onset epilepsy according to the International League AgainstEpilepsy (ILAE) Classification of Epilepsy.

2. Past evidence by computed tomography (CT) or magnetic resonance imaging (MRI) thathas ruled out a progressive cause of epilepsy in the judgement of the investigatorand/or in consultation with the medical monitor.

Exclusion Criteria:

1. Subject has had any of the of the following within the 12-month period precedingtrial entry: History of pseudo or psychogenic seizures, cluster seizures where theindividual seizures cannot be counted, an episode of convulsive status epilepticusrequiring hospitalization and intubation, or subject only has focal seizures withawareness that do not have motor activity.

2. Planned epilepsy surgery during the course of the clinical trial.

3. History of neurosurgery for seizures <1 year prior to enrollment, or radiosurgery <2years prior to enrollment or vagus nerve stimulation (VNS) implantation.

4. History of schizophrenia, obsessive-compulsive disorder, or other serious mentalhealth disorders.

5. History of malignancy, myeloproliferative or lymphoproliferative disorders withinthe past 5 years are excluded.

6. History of cardiac disease(s)/cardiac conduction disorders/or cardiac structuralabnormality(ies).

7. Has a positive test result or a known history of a positive test result for humanimmunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), or anti-hepatitisC virus (HCV) antibody at Screening.

8. Is pregnant or is breastfeeding at the time of Screening or has a positive serumpregnancy test at Screening or is planning to become pregnant during the clinicaltrial or within 14 days of the last study drug dose.

9. Has received any other experimental or investigational drug, device or other therapywithin 30 days or 5 half-lives (whichever is longer) prior to Screening, or anyprior use of gene therapy.