Pharmacokinetics, Efficacy and Tolerability of BIA 2-093

Inclusion Criteria: The following inclusion criteria were applied in selecting patients for participation in the trial. Patient was eligible for entry into the baseline phase if he/she fulfilled the following criteria at Visit 1: * Written informed consent given by the parent(s)/guardian(s), and by the patient when appropriate. * Male or female patient aged between 2 and 17 years. * Body weight within the 10th and 90th percentiles, by age and sex. * A documented diagnosis of partial-onset seizures (simple or complex seizures with or without secondary generalisation), classified according to the International Classification of Epileptic Seizures. * Currently treated with 1 to 3 AEDs (any except OXC or CBZ), in a stable dosage regimen during at least 1 month prior to screening. * Good general health (apart from epilepsy) based on medical history and physical examination. * In case of a female patient, she was premenarchal, surgically sterile or presented a urine pregnancy test consistent with a non-gravid state and practiced an effective non-hormonal contraception method. At Visit 2, patient was eligible for entry into the Eslicarbazepine acetate treatment phase if he/she fulfilled the following criteria: * At least 4 partial-onset seizures during the last 4 weeks of the baseline phase. * Brain CT scan or MRI that excluded rapidly progressive neurological diseases. * ECG without clinically significant abnormalities. * Good general health (apart from epilepsy) based on medical history, physical examination and laboratory tests at screening. * Diaries satisfactorily completed by the patient or his/her caregiver during the baseline phase. * Satisfactory compliance with the study requirements during the baseline phase. * In case of a female patient of childbearing potential, she presented a urine pregnancy test consistent with a non-gravid state and practiced an effective non-hormonal contraception method. Exclusion Criteria: Patient was not allowed for entry into the screening phase if he/she fulfilled the following criteria at Visit 1: * Primarily generalised epilepsy. * Clinically relevant medical condition, other than epilepsy. * History of status epilepticus in the last 3 months. * History of suicide attempt. * History of alcohol or drug abuse. * History of hypersensitivity or intolerance to OXC or CBZ. * Use of any investigational drug or participated in any clinical trial within the previous 2 months. * Patient and/or his/her caregiver(s) unlikely to co-operate with the requirements of the study. * If female, she was sexually active and of child-bearing potential and she did not use reliable contraception. * Patients with non-epileptic attacks (syncopes, pseudoseizures). * Previous poor compliance with anti-epileptic therapy. * Need for rescue benzodiazepines more frequently than twice per week on average. * Previous use of Eslicarbazepine acetate or participation in a clinical study with Eslicarbazepine acetate. * Any other condition or circumstance that, in the opinion of the investigator, might compromise the patient's ability to comply with the clinical trial protocol (CTP). At Visit 2, patient was not eligible for entry into the Eslicarbazepine acetate treatment phase if he/she fulfilled the following criteria: * Inadequate compliance to concomitant AEDs during the baseline phase. * Clinically relevant clinical laboratory test abnormalities at screening. * Occurrence of any other condition or circumstance that, in the opinion of the investigator, might compromise the patient's ability to comply with the CTP.