The Effect of Horizant (Gabapentin Enacarbil) on Augmentation (XP-IIT-0034)

To Examine the Effect of Horizant (Gabapentin Enacarbil) in Primary Restless Legs Syndrome (RLS) Patients Who Are on Dopaminergic Agents and Exhibiting Augmentation

Restless Legs Syndrome (RLS) is a common neurological disorder. Augmentation is the main complication during long-term DA treatment of RLS. This study aims to examine effect of Horizant (Gabapentin Enacarbil) on Augmentation in RLS patients.

Study Overview

• Status: Completed
• Conditions: Restless Legs Syndrome
• Intervention / Treatment: Drug: Horizant

Detailed Description

This is an Open label single arm study. The purpose of the study is to demonstrate the efficacy of Horizant in patients with RLS who exhibit augmentation while on Dopaminergic therapy. Adult patients (age 18-85 years) with diagnosis of primary RLS (diagnosed by study investigators) with augmentation on dopaminergic therapy will be screened for participation in the study. RLS diagnosis will be made by the study investigators using International RLS study group criteria. Patients with augmentation on dopaminergic therapy as defined by NIH 2007 with ASRS of 5 to 15 will be offered to participate in the study. Inclusion and exclusion criteria are listed below. The study will be performed after approval of the Institutional Review Board of the University of Missouri.

A total of 50 subjects will be entered into the study over a period of 1 year. Written consent will be obtained from all patients. After pre-participation evaluation for eligibility, subjects will be selected and enrolled in the study and followed for a total of 6 follow up visits (Days 0, 30, 90, 120, 180, 360). Subjects Enrollment period will last up to 12 months. The total duration of study will be 24 months.

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Missouri
    • Columbia, Missouri, United States, 65212
      • University of Missouri Health Care

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years to 83 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Adult patients with diagnosis of RLS for more than one year.
2. Patients who are on DA therapy for 6 months or longer.
3. Patients who developed Augmentation (on stable dose of DA) lasting for 3 months or longer.
4. Augmentation severity rating scale of 5 to 15.
5. Both males and females
6. Age range = 18-85 year

Exclusion Criteria:

• Known Hypersensitivity to Horizant or Gabapentin products
• Peripheral neuropathy
• Radiculopathy
• Peripheral vascular disease
• Uremia [abnormal blood urea nitrogen (BUN) or Creatinine on Comprehensive Metabolic Panel (CMP)]
• Anemia
• Patients who are currently pregnant
• Patients who currently take opioids, lithium, anti-nausea medications (e.g. metoclopramide), dopaminergic antagonists (e.g. Haloperidol), 1st generation antihistamines (e.g. diphenhydramine, pseudoephedrine), anti-psychotic medications and iron therapy.
• Subjects with impaired decision making capability.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Other: open-label; open-label single arm study Horizant, 600 mg oral once daily at 5 pm for 360 days.

Drug: Horizant; Phase1: During phase 1 therapy, Horizant will be added on as an adjunct to all subjects taking part in the study along with stable dose of their current dopaminergic (DA) agent and both medication will be continued for a total period of 90 days from day 0 to day 90. Subjects will be evaluated for three visits (days 0, 30 and 90) during Phase I. Phase 2: At the 90th day follow-up visit, with initiation of phase 2 therapy, all subjects will be tapered off (by 50% reduction in dose each week) of their current dopaminergic agents while maintaining the same dose of Horizant and will be on Horizant monotherapy. All subjects will be evaluated for additional three clinic visits (days 120, 180, 360).; Other Names: Gabapentin enacarbil

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Augmentation Severity From Day 0 to Day 90	Augmentation severity rating scale; 0-24, 0 is better, 24 is worst	From Day 0 (Baseline) to Day 90

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Augmentation Severity Rating Scale Form Day 0 to Day 360 (270 Days After Discontinuation pf Dopaminergic Medication)	Numeric Scale to assess degree of augmentation; Range 0-24; 0 is better, 24 is worst. We compared the Augmentation severity scale on day 0 to day 360 (which is 270 days after this decrease of dopaminergic medication)	Day 0 to day 360 (270 days after discontinuing dopaminergic medication)

Collaborators and Investigators

• Sponsor: University of Missouri-Columbia
• Investigators: Principal Investigator: Pradeep Sahota, MD, University of Missouri Health Care

Study record dates

Study Major Dates

• Study Start: January 1, 2016
• Primary Completion (Actual): May 6, 2019
• Study Completion (Actual): May 6, 2019

Study Registration Dates

• First Submitted: November 13, 2015
• First Submitted That Met QC Criteria: December 23, 2015
• First Posted (Estimate): December 30, 2015

Study Record Updates

• Last Update Posted (Actual): February 24, 2022
• Last Update Submitted That Met QC Criteria: February 1, 2022
• Last Verified: February 1, 2022

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mental Disorders; Pathologic Processes; Nervous System Diseases; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Neurologic Manifestations; Neurobehavioral Manifestations; Disease; Dyskinesias; Psychomotor Disorders; Parasomnias; Syndrome; Psychomotor Agitation; Restless Legs Syndrome; Physiological Effects of Drugs; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Central Nervous System Depressants; Peripheral Nervous System Agents; Analgesics; Sensory System Agents; Excitatory Amino Acid Antagonists; Excitatory Amino Acid Agents; Tranquilizing Agents; Psychotropic Drugs; Anti-Anxiety Agents; Anticonvulsants; Antimanic Agents; Gabapentin
• Other Study ID Numbers: 2002392

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No