An Efficacy and Safety Evaluation of HORIZANT in Adolescents With Moderate-to-Severe Primary RLS

Inclusion Criteria:

1. Male and female adolescent patients, aged 13 to 17 years, diagnosed with RLS based onthe IRLSSG consensus criteria (Allen RP 2014) (Appendix 2).
2. Total RLS severity score of 15 or greater on the IRLS rating scale at Visit 1 (screening) and at Visit 2 (baseline) (Appendix 8).
3. RLS symptoms for at least 4 of 7 consecutive evenings/nights during the screeningperiod.
4. Body weight greater than 33.4 kg and a healthy weight using age-based body mass index (BMI) range 5th-95th percentile at screening and baseline.
5. Negative pregnancy test for all females at screening and baseline. Sexually activepatients must agree to use 2 medically accepted methods of contraception, 1 of whichis a highly effective method (e.g., hormonal or intrauterine device [IUD]) [the secondmay be a barrier method (e.g., male condom, female condom, diaphragm or cervicalcap)], during the course of the study treatment and for 4 weeks after the last dose ofstudy treatment. For patients using hormonal contraceptives as one of the methods, thecontraceptive should be stabilized for at least 3 months prior to screening. Female patients who normally abstain from sexual activity may be recruited, providingthey remain abstinent during the study, or if they become sexually active, they mustagree to use 2 effective methods of birth control as described above.
6. Male patients must agree to use a barrier method (male condom, female condom,diaphragm, or cervical cap) with spermicide for at least 30 days prior to dosing andthroughout the study, if sexually active. Male patients who normally abstain fromsexual activity may be recruited, providing they remain abstinent during the study, orif they become sexually active, they must agree to use a barrier method as describedabove.
7. Estimated creatinine clearance of at least 60 mL/min (using the Cockcroft-Gaultequation) at screening only.
8. Appropriate cognitive and communication skills, as judged by the clinician, needed tocomplete study assessments.
9. Signed patient and parent Institutional Review Board (IRB)-approved informedconsent/assent form (as applicable) before any study-related procedures are performed.
10. Willing and able to follow the study procedures.

Exclusion Criteria:

1. History of a primary sleep disorder other than RLS that may significantly affect thesymptoms of RLS.
2. Serum ferritin level < 20 ng/mL at screening.
3. History of allergy, hypersensitivity, or intolerance to HORIZANT or any othergabapentin products (e.g., Neurontin®, Gralise®).
4. Suffering from an isolated periodic limb movement disorder without RLS.
5. Currently meet Diagnostic and Statistical Manual of Mental Disorders - Fifth Edition (DSM-5) criteria for substance use disorder, or history thereof, within 12 monthsbefore dosing.
6. Current or past history of any significant psychiatric disorder including, but notlimited to, depression (treatment with antidepressants), bipolar disorder, orschizophrenia.
7. Diagnosis of ADHD is allowed, provided the patient is not receiving medication(s)known to affect the assessment of RLS.
8. History of suicidal behavior or suicidal ideation as indicated by the C-SSRS,administered at screening, and as per investigator's judgment.
9. Patients with a history of epilepsy, subjects currently prescribed treatments forepilepsy, or subjects with a history of seizure in the last 5 years.
10. Medical condition or disorder that would interfere with the action, absorption,distribution, metabolism, or excretion of gabapentin enacarbil, or, in the PrincipalInvestigator's judgment is considered to be clinically significant and may pose asafety concern, or, could interfere with the accurate assessment of safety orefficacy, or could potentially affect a patient's safety or study outcome.
11. In the judgement of the Principal Investigator, clinically significant, abnormallaboratory result or physical examination finding not resolved by the time of baselineassessments.
12. Positive test for hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV)antibody, human immunodeficiency virus (HIV) antibody at screening.
13. Uncontrolled hypertension defined as blood pressure (BP) ≥ 95 percentile adjusted forage, height, and sex, according to the tables published by the US Department of Healthand Human Services 2005, at screening and before dosing. Appendix 5 contains thetables that can be consulted.
14. Participated in an investigational drug trial within the 4 weeks before dosing orplans to participate in another study at any time during this study.
15. Received an investigational product within 6 months prior to dosing.