An Extension Study to Evaluate the Efficacy and Safety of HORIZANT in Adolescents With Moderate-to-Severe Primary RLS

Patients who complete the 12-week daily dosing efficacy and safety study (XP109) will be allowed to enroll in the open-label extension (OLE) study (XP110), thereby providing exposure to HORIZANT for up to 48 weeks. Enrolled patients will take open-label HORIZANT 600 mg tablets once a day at approximately 5 PM with food, beginning at Week 0 of the OLE study up to and including Week 36. After the end of the treatment period, a follow-up visit will be included 14 days (± 3 days) after the last dose of HORIZANT. Patients will visit the clinical site on 6 different occasions, including a follow-up visit 14 days (± 3 days) after the last dose of study drug.