XP13512 (Gabapentin Enacarbil) Extension Study in Patients With Restless Legs Syndrome.

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
XenoPort, Inc.
ClinicalTrials.gov Identifier:
NCT00333359
First received: June 1, 2006
Last updated: July 15, 2013
Last verified: May 2011
  Purpose

The primary objective of this trial is to assess the long-term safety and efficacy of XP13512 (Gabapentin Enacarbil) taken once daily for the treatment of patients suffering from Restless Legs Syndrome (RLS).


Condition Intervention Phase
Restless Legs Syndrome
Drug: XP13512 (GEn)
Phase 3

Study Type: Interventional
Study Design: Endpoint Classification: Safety/Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: An Open-Label, 52-Week Extension Study Assessing XP13512 Safety and Efficacy in Patients With Restless Legs Syndrome.

Resource links provided by NLM:


Further study details as provided by XenoPort, Inc.:

Primary Outcome Measures:
  • Change From Baseline in the International Restless Legs Syndrome Rating Scale (IRLS) at Week 52 Using Observed Case (OC) [ Time Frame: Baseline and Week 52 ] [ Designated as safety issue: No ]
    The IRLS rating scale is a measure of RLS disease severity. The score reflects participant-reported assessment of primary sensory and motor features and associated sleep problems in RLS. Also, items are included that assess the impact of symptoms on participants' mood, daily life, and activities. The total score on the IRLS ranges from 0 to 40, with higher values representing more severe RLS symptoms. Change from baseline was calculated as the Week 52 value minus the baseline value. Change scores with higher value represents greater improvement in RLS symptoms.

  • Number of Participants Classified as Responders to Treatment on the Investigator-rated Clinical Global Impressions of Improvement (CGI-I) at Each Visit Using OC [ Time Frame: Weeks 0, 1, 4, 12, 24, 36, and 52 ] [ Designated as safety issue: No ]
    The CGI-I is a widely used tool designed to allow clinicians to rate the severity of illness and the change over time based on a seven-point rating scale, with a score of 1 being "very much improved" and a score of 7 being "very much worse" compared to the start of the study. Responders on the CGI-I are defined as those with a score of 1 or 2, corresponding to "very much improved" or "improved," respectively.


Secondary Outcome Measures:
  • Change From Baseline in the IRLS Rating Scale Score at Each Visit Using OC [ Time Frame: Weeks 0, 1, 4, 12, 24, and 36 ] [ Designated as safety issue: No ]
    The IRLS rating scale is a measure of RLS disease severity. The score reflects participant-reported assessment of primary sensory and motor features and associated sleep problems in RLS. Also, items are included that assess the impact of symptoms on participants' mood, daily life, and activities. The total score on the IRLS ranges from 0 to 40, with higher values representing more severe RLS symptoms. Change from baseline was calculated as the value at each visit minus the baseline value. Change scores with higher values represent greater improvement in RLS symptoms.

  • Number of Participants in Each Category of the Investigator-rated CGI-I by Visit Using OC [ Time Frame: Weeks 0, 1, and 52 ] [ Designated as safety issue: No ]
    The CGI-I is a widely used tool designed to allow clinicians to rate the severity of illness and the change over time based on a seven-point rating scale, with a score of 1 being "very much improved," 2 being "much improved," 3 being "minimally improved," 4 being "no change," 5 being "minimally worse," 6 being "much worse," and 7 being "very much worse" compared to the start of the study.

  • Number of Participants Classified as Responders to Treatment on the Participant-rated CGI-I at Each Visit Using OC [ Time Frame: Weeks 0, 1, 4, 12, 24, 36, and 52 ] [ Designated as safety issue: No ]
    The Participant-rated CGI-I is a self-reported measure completed by the participant, who rates the change from the start of the study in the severity of their illness using a seven-point rating scale, with a score of 1 being "very much improved" and a score of 7 being "very much worse". Responders on the Participant-rated CGI-I are defined as those with a score of 1 or 2, corresponding to "very much improved" and "improved," respectively.

  • Number of Participants in Each Category of the Participant-rated CGI-I by Visit Using OC [ Time Frame: Weeks 0, 1, and 52 ] [ Designated as safety issue: No ]
    The Participant-rated CGI-I is a self-reported measure completed by the participant who rates the change from the start of the study in the severity of their illness using a seven-point rating scale, with a score of 1 being "very much improved," 2 being "much improved," 3 being "minimally improved," 4 being "no change," 5 being "minimally worse," 6 being "much worse," and 7 being "very much worse" compared to the start of the study.

  • Number of Participants With no Reported RLS Symptoms During Each of the 4-hour Periods From the 24-hour RLS Record at Week 52 Using OC Data [ Time Frame: Week 52 ] [ Designated as safety issue: No ]
    In the 24-Hour RLS Record (diary), participants report the presence and severity of RLS symptoms (none, mild, moderate, or severe) for a 24-hour period, in 30-minute increments. The period was divided into 7 four-hour intervals (8 AM to 12PM, 12 to 4PM, 4 to 8PM, 6 to 10PM, 8 to 12 Midnight, Midnight to 4AM, 4 to 8AM).

  • Median Time to Onset of the First RLS Symptom Using the RLS Symptom Record at Weeks 24 and 52 [ Time Frame: Weeks 24 and 52 ] [ Designated as safety issue: No ]
    The 24-Hour RLS Record is a diary in which participants report the presence and severity of RLS symptoms for a 24-hour period, in 30-min increments, beginning at 8AM on the day prior to the visit.

  • Overall Quality of Life (QoL) Impact Score of the RLS Quality of Life Questionnaire at Weeks 24 and 52 [ Time Frame: Weeks 24 and 52 ] [ Designated as safety issue: No ]
    The RLS QoL is an 18-item scale assessing the impact of RLS on daily life, emotional well-being, social and work life. Responses range from 1 (not at all/never) to 5 (a lot/all of the time). Ten items contribute to a single summary score, the Overall Life Impact, which is standardized to range from 0-100, with lower scores representing better QoL.

  • Mean Change From Baseline at Week 24 and Week 52 in Work Productivity and Activity Impairment Questionnaire (WPAI:SHP) Summary Scores [ Time Frame: Baseline and Weeks 24 and 52 ] [ Designated as safety issue: No ]
    The WPAI:SHP estimates work productivity and social activities lost over the past week due to RLS symptoms. Each summary score is expressed as a percentage and ranges from 0 to 100, with higher scores indicating more work missed; a negative change from baseline indicates less work missed. Change = the observed value at the current visit minus the observed value at Week 0. Change is calculated only for participants who had a value at both the current visit and at Week 0.

  • Mean Change From Baseline at Week 24 and Week 52 in Work Productivity and Activity Impairment Questionnaire (WPAI:SHP) Individual Items: Hours of Work Missed Due to RLS, Hours of Work Missed Due to Other Reason, and Hours Actually Worked [ Time Frame: Baseline and Weeks 24 and 52 ] [ Designated as safety issue: No ]
    The WPAI:SHP estimates work productivity and social activities lost over the past week due to RLS symptoms. Change is calculated as the observed value at Week 24/52 minus the observed value at baseline. Absenteeism is recorded as the number of hours missed from work. W, Week; hr, hour.

  • Mean Change From Baseline at Weeks 24 and 52 in Work Productivity and Activity Impairment Questionnaire (WPAI:SHP) Individual Item: RLS Affected Productivity [ Time Frame: Baseline and Weeks 24 and 52 ] [ Designated as safety issue: No ]
    The WPAI:SHP estimates work productivity and social activities lost over the past week due to RLS symptoms. Change is calculated as the observed value at Week 52 minus the observed value at baseline. Productivity affected while working is estimated on a 0 (no effect) to 10 scale (completely preventing productivity).


Enrollment: 581
Study Start Date: June 2006
Study Completion Date: December 2008
Primary Completion Date: December 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: XP13512 (GEn)
1200 mg XP13512, orally, once daily for 52 weeks
Drug: XP13512 (GEn)
1200 mg XP13512, orally, once daily for 52 weeks
Other Names:
  • GSK1838262
  • Gabapentin Enacarbil

Detailed Description:

Study XP055 is a multicenter, open-label, 52-week extension study of XP13512 (Gabapentin Enacarbil [GEn]) given once daily to eligible subjects with Restless Legs Syndrome (RLS) who had previously completed 1 of the following studies and met eligibility criteria: XP052 (110963 [NCT00298623]), XP053 (111460 [NCT00365352]), XP081 (111462 [NCT01332305]), and XP083 (111463 [NCT01332318]).

  Eligibility

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Patients who have successfully completed one of the following studies: XP052 (110963 [NCT00298623]), XP053 (111460 [NCT00365352]), XP081 (111462 [NCT01332305]), and XP083 (111463 [NCT01332318]).

Exclusion Criteria:

  • Subjects who, in the opinion of the Investigator, would be non-compliant with the study visit schedule, procedures, or medication administration.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00333359

Sponsors and Collaborators
XenoPort, Inc.
Investigators
Study Director: GSK Clinical Trials GlaxoSmithKline
  More Information

Publications:
Responsible Party: XenoPort, Inc.
ClinicalTrials.gov Identifier: NCT00333359     History of Changes
Other Study ID Numbers: 111490
Study First Received: June 1, 2006
Results First Received: April 28, 2011
Last Updated: July 15, 2013
Health Authority: United States: Food and Drug Administration

Additional relevant MeSH terms:
Psychomotor Agitation
Restless Legs Syndrome
Syndrome
Dyskinesias
Neurologic Manifestations
Nervous System Diseases
Psychomotor Disorders
Neurobehavioral Manifestations
Signs and Symptoms
Sleep Disorders, Intrinsic
Dyssomnias
Sleep Disorders
Parasomnias
Mental Disorders
Disease
Pathologic Processes
Gabapentin
Gamma-Aminobutyric Acid
Analgesics
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Pharmacologic Actions
Central Nervous System Agents
Therapeutic Uses
Anticonvulsants
Antiparkinson Agents
Anti-Dyskinesia Agents
Calcium Channel Blockers
Membrane Transport Modulators

ClinicalTrials.gov processed this record on September 22, 2014