Trial · NCT01668667

Gabapentin Enacarbil (GSK1838262) Adult Restless Leg Syndrome (RLS) Post Marketing Commitment Study

NCT01668667, Phase 4, Completed, XenoPort, Inc.; results first posted 2014-11-17

3 sourcestrials-2026-11-12-0.5.0

Cite this record

ConductScience Library. Gabapentin Enacarbil (GSK1838262) Adult Restless Leg Syndrome (RLS) Post Marketing Commitment Study. Trials, record NCT01668667. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT01668667

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Trial

As registered on ClinicalTrials.gov, in the graph's capture of the registry.

Title: Gabapentin Enacarbil (GSK1838262) Adult Restless Leg Syndrome (RLS) Post Marketing Commitment Study
NCT number: NCT01668667
Status: Completed
Phases: Phase 4
Enrollment: 501 participants, actual
Lead sponsor: XenoPort, Inc.
Conditions: Restless Legs Syndrome
Interventions: GSK1838262 600 mg, GSK1838262 450 mg, GSK1838262 300 mg, GSK1838262 Placebo match
First posted: 2012-08-20
Last updated: 2021-05-24
Results first posted: 2014-11-17

Source ClinicalTrials.gov

Registered outcomes4

Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.

List	Outcome	Time frame	Description
Primary	The Change From Baseline to the End of Treatment in the International Restless Legs Syndrome (IRLS) Rating Scale Score	Baseline, 12 weeks	International Restless Legs Syndrome Rating Scale: Very severe=31-40, Severe=21-30, Moderate=11-20, Mild=1-10, None=0. Change from Baseline = LOCF value at current visit - value at Baseline (the last nonmissing assessment before the first dose of study medication). A negative treatment difference indicates a benefit relative to placebo. The change from baseline data is analyzed using an ANCOVA model with treatment and pooled site as the main effects and the baseline IRLS Rating Scale total score as a covariate.
Primary	The Proportion of Subjects at the End of Treatment Who Are Responders With Either "Much Improved" or "Very Much Improved" on the Investigator-rated Clinical Global Impression of Improvement (CGI-I)	12 weeks	Clinical Global Impression - Improvement Scale (CGI-I): 7-point clinician rated scale ranging from 1 (very much improved) to 7 (very much worse). Improvement is defined as a score of 1 (very much improved), 2 (much improved), on the scale. Higher score = more affected. Number of subjects responding to treatment at Week 12 with respect to dose level. CGI-I Responders = subjects who reported CGI-I scores of very much improved or much improved.
Secondary	The Dose-response Relationship of Change From Baseline in IRLS Rating Scale Total Score at End of Treatment	Baseline, 12 Weeks	International Restless Legs Syndrome Rating Scale: Very severe=31-40, Severe=21-30, Moderate=11-20, Mild=1-10, None=0. This model only includes treatment in the model. Least squares mean is used for analysis.
Secondary	The Dose-response Relationship for Investigator-rated CGI-I Scale at End of Treatment	12 Weeks

Source ClinicalTrials.gov

Outcomes4

Each outcome the trial posted results for, in ClinicalTrials.gov's words.

Type	Outcome	Time frame	Population	Units	Measured as
PRIMARY	The Change From Baseline to the End of Treatment in the International Restless Legs Syndrome (IRLS) Rating Scale Score	Baseline, 12 weeks	mITT (modified intent to treat) Population: The mITT population will include all randomly assigned subjects who received at least 1 dose (or any portion of a dose) of study medication as defined above for the Safety population, have a baseline IRLS Rating Scale total score, and have at least 1 on-treatment IRLS Rating Scale total score.	units on a scale	MEAN
PRIMARY	The Proportion of Subjects at the End of Treatment Who Are Responders With Either Much Improved or Very Much Improved on the Investigator-rated Clinical Global Impression of Improvement (CGI-I)	12 weeks	mITT (modified intent to treat) population: The mITT population will include all randomly assigned subjects who received at least 1 dose (or any portion of a dose) of study medication as defined above for the Safety population, have a baseline IRLS Rating Scale total score, and have at least 1 on-treatment IRLS Rating Scale total score.	percentage of participants	NUMBER
SECONDARY	The Dose-response Relationship of Change From Baseline in IRLS Rating Scale Total Score at End of Treatment	Baseline, 12 Weeks	mITT (modified intent to treat) Population: The mITT population will include all randomly assigned subjects who received at least 1 dose (or any portion of a dose) of study medication as defined above for the Safety population, have a baseline IRLS Rating Scale total score, and have at least 1 on-treatment IRLS Rating Scale total score.	units on a scale	LEAST_SQUARES_MEAN
SECONDARY	The Dose-response Relationship for Investigator-rated CGI-I Scale at End of Treatment	12 Weeks	mITT (modified intent to treat) Population: The mITT population will include all randomly assigned subjects who received at least 1 dose (or any portion of a dose) of study medication as defined above for the Safety population, have a baseline IRLS Rating Scale total score, and have at least 1 on-treatment IRLS Rating Scale total score.	percentage of participants	NUMBER

Source ClinicalTrials.gov

Results by group20

Each measurement the trial posted, group by group, in the words and numbers it posted.

Outcome	Group	Value	Spread	Units
The Change From Baseline to the End of Treatment in the International Restless Legs Syndrome (IRLS) Rating Scale Score	GSK1838262 600 mg	-12.50	Standard Error 0.745	units on a scale
The Change From Baseline to the End of Treatment in the International Restless Legs Syndrome (IRLS) Rating Scale Score	GSK1838262 450 mg	-12.54	Standard Error 0.764	units on a scale
The Change From Baseline to the End of Treatment in the International Restless Legs Syndrome (IRLS) Rating Scale Score	GSK1838262 300 mg	-11.48	Standard Error 0.767	units on a scale
The Change From Baseline to the End of Treatment in the International Restless Legs Syndrome (IRLS) Rating Scale Score	GSK1838262 Placebo Match	-9.93	Standard Error 0.753	units on a scale
The Proportion of Subjects at the End of Treatment Who Are Responders With Either Much Improved or Very Much Improved on the Investigator-rated Clinical Global Impression of Improvement (CGI-I)	GSK1838262 600 mg	67		percentage of participants
The Proportion of Subjects at the End of Treatment Who Are Responders With Either Much Improved or Very Much Improved on the Investigator-rated Clinical Global Impression of Improvement (CGI-I)	GSK1838262 450 mg	67		percentage of participants
The Proportion of Subjects at the End of Treatment Who Are Responders With Either Much Improved or Very Much Improved on the Investigator-rated Clinical Global Impression of Improvement (CGI-I)	GSK1838262 300 mg	68		percentage of participants
The Proportion of Subjects at the End of Treatment Who Are Responders With Either Much Improved or Very Much Improved on the Investigator-rated Clinical Global Impression of Improvement (CGI-I)	GSK1838262 Placebo Match	50		percentage of participants
The Dose-response Relationship of Change From Baseline in IRLS Rating Scale Total Score at End of Treatment	GSK1838262 600 mg	-12.1	Standard Error 0.80	units on a scale
The Dose-response Relationship of Change From Baseline in IRLS Rating Scale Total Score at End of Treatment	GSK1838262 450 mg	-12.7	Standard Error 0.82	units on a scale

1 to 10 of 20Source ClinicalTrials.gov

See all 20 results by group

Participant flow12

How many started, completed or left each group, period by period.

Period	Milestone	Group	Participants
Overall Study	STARTED	GSK1838262 600 mg	126
Overall Study	STARTED	GSK1838262 450 mg	125
Overall Study	STARTED	GSK1838262 300 mg	125
Overall Study	STARTED	GSK1838262 Placebo Match	125
Overall Study	COMPLETED	GSK1838262 600 mg	95
Overall Study	COMPLETED	GSK1838262 450 mg	99
Overall Study	COMPLETED	GSK1838262 300 mg	94
Overall Study	COMPLETED	GSK1838262 Placebo Match	102
Overall Study	NOT COMPLETED	GSK1838262 600 mg	31
Overall Study	NOT COMPLETED	GSK1838262 450 mg	26

1 to 10 of 12Source ClinicalTrials.gov

See all 12 participant flow

Adverse events40

Each adverse event the trial posted, group by group: the participants affected out of those at risk.

Type	Event	Organ system	Group	Affected	At risk
other	Somnolence	Nervous system disorders	GSK1838262 600 mg	13	122
other	Somnolence	Nervous system disorders	GSK1838262 450 mg	20	123
other	Somnolence	Nervous system disorders	GSK1838262 300 mg	12	121
other	Somnolence	Nervous system disorders	GSK1838262 Placebo Match	8	121
other	Headache	Nervous system disorders	GSK1838262 600 mg	11	122
other	Headache	Nervous system disorders	GSK1838262 450 mg	9	123
other	Headache	Nervous system disorders	GSK1838262 300 mg	10	121
other	Headache	Nervous system disorders	GSK1838262 Placebo Match	12	121
other	Dizziness	Nervous system disorders	GSK1838262 600 mg	15	122
other	Dizziness	Nervous system disorders	GSK1838262 450 mg	8	123

1 to 10 of 40Source ClinicalTrials.gov

See all 40 adverse events

Adverse event totals12

The totals the trial posted for each group.

Total	Group	Affected	At risk
Total, all-cause mortality	GSK1838262 600 mg
Total, all-cause mortality	GSK1838262 450 mg
Total, all-cause mortality	GSK1838262 300 mg
Total, all-cause mortality	GSK1838262 Placebo Match
Total, other adverse events	GSK1838262 600 mg	55	122
Total, other adverse events	GSK1838262 450 mg	56	123
Total, other adverse events	GSK1838262 300 mg	33	121
Total, other adverse events	GSK1838262 Placebo Match	46	121
Total, serious adverse events	GSK1838262 600 mg	1	122
Total, serious adverse events	GSK1838262 450 mg	0	123

1 to 10 of 12Source ClinicalTrials.gov

See all 12 adverse event totals

Papers0

The papers the trial lists on ClinicalTrials.gov.

None in this release.

Grants0

The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.

None in this release.

Trial comparisons0

Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.

None in this release.

Tests0

The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.

None in this release.

Data dates

The day each source was copied for this release.

ClinicalTrials.gov: 2026-11-12; ClinicalTrials.gov
Results, from AACT: 2026-03-23; AACT
NIH grant links: 2026-11-13; NIH RePORTER

Sources 3

ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
ClinicalTrials.govNo license stated
NIH RePORTER's clinical studies and project filesPublic domain

Each source's terms

ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
ClinicalTrials.govnone stated
NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)

ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.

For software

Read this trial from software.

The record and each of its lists are JSON, twenty rows a page. No key.

GET https://conductscience.org/api/trials/v1/NCT01668667

GET https://conductscience.org/api/trials/v1/NCT01668667/events?page=2

API reference For AI assistants