Part II was a 1-year open-label extension for patients who had completed Part I. Starting at 800 mg/day, the dosage could be titrated at 400 mg intervals down to a minimum of 400 mg/day or up to a maximum of 1200 mg/day. Patients who completed Part II could participate in a study extension and continue treatment with ESL until marketing authorization is obtained or clinical development is discontinued, with visits scheduled at the discretion of the investigator but at least every 6 months.