Outpatients ≥ 50 kg (110 lb) of weight

A diagnosis of epilepsy (≥ 2 years prior to screening) with partial seizures with or without secondarily generalized seizures

Uncontrolled partial seizures despite having been treated with at least two different AEDs within the last 2 years prior to screening.

Treated with a stable dose of 1-2 AEDs

At least 4 partial seizures during the 4-week baseline period and at least 4 partial seizures during the 4 weeks prior to the baseline period.

No 28-day seizure-free period during the 8 weeks preceding randomization

Positive biomarker screening

Evaluate the Efficacy of BGG492 as Adjunctive Treatment in Patients With Refractory Partial Onset Seizures