Safety Study of Rufinamide Given as an add-on Therapy to Treat Patients With Seizures

Inclusion Criteria: * Male and Female patients between 12 and 80 years of age * Dx of epilepsy with partial onset seizures woth or woth out secondarily generalized seizures * Non controlled partial seizures despite treatment with 2 different AEDs for at least 2 years * must have 6 seizures during baseline * current treatment with maximum of 3 AEDs * stable dose of AED(s)for at least 1 month * if patient has VNS, must have been implanted 6 months prior to randomization Exclusion Criteria: * Participation in any investigational product for at least 1 month prior to visit 1 * Presence of non-motor simple partial seizures only * presence of generalized epilepsies * Evidence of clinically significant disease * Clinically significant ECG * Psychogenic seizure in previous year * History of drug/alcohol abuse * History of suicide attempt * Multiple drug allergies * Concomitant felbamate use * Need for frequent rescue benzodiazepines * Concomitant use of vigabatrin * All patients diagnosed with congenital short QT syndrome