Study Evaluating the Efficacy and Safety of RAP-219 in Adult Participants With Focal Seizures FOCUS-1

Approximately 333 subjects will be randomized into one of two active treatment groups or placebo in a 1:1:1 randomization ratio (High Dosage, Medium Dosage and Placebo). After completing the Double-blind Treatment Period, participants will either transition into the RAP-219-FOS-901 long-term safety (open-label extension) study or enter the 8-week post-treatment Follow-up Period of this study.

Inclusion criteria

• Age 18 - 75
• BMI 18-45 kg/m2
• Diagnosis of focal epilepsy for ≥24 months prior to Visit 1
• Report from at least 1 brain MRI or CT scan and 1 EEG study, each completed within 10 years prior to Visit 1, consistent with focal epilepsy diagnosis
• Concomitant use of between 1 and 3, inclusive, antiseizure medication(s) ASM(s) as maintenance, not including rescue or pro re nata (PRN) ASMs
• Ability to keep accurate daily focal seizure records using an e-diary

Exclusion criteria

• Known hypersensitivity or prior exposure to RAP-219.
• Unstable or uncontrolled serious medical, neurologic (other than focal epilepsy), or psychiatric condition that is ongoing or considered likely to recur
• Anticipated need for surgery during the study period
• Medical history of any of the following:

• generalized epilepsy
• focal preserved consciousness without observable manifestations (also known as focal aware nonmotor) as the participant's only seizure type
• psychogenic nonepileptic seizure (PNES)
• status epilepticus or seizure clusters (when individual seizures cannot be counted) within 12 months prior to Visit 1 (Day -56).
• epilepsy surgery within 12 months prior to Visit 1 (Day -56).
• Participation in another clinical study of an investigational product within 12 weeks or 5 half-lives of this other investigational product