Trial · NCT00311363
Long-Term Study of Gabapentin Enacarbil (GEn, XP13512) vs. Placebo in Patients With Restless Legs Syndrome.
NCT00311363, Phase 3, Completed, XenoPort, Inc.; results first posted 2011-05-25
3 sourcestrials-2026-11-12-0.5.0
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ConductScience Library. Long-Term Study of Gabapentin Enacarbil (GEn, XP13512) vs. Placebo in Patients With Restless Legs Syndrome. Trials, record NCT00311363. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT00311363
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Trial
As registered on ClinicalTrials.gov, in the graph's capture of the registry.
- Title
- Long-Term Study of Gabapentin Enacarbil (GEn, XP13512) vs. Placebo in Patients With Restless Legs Syndrome.
- NCT number
- NCT00311363
- Status
- Completed
- Phases
- Phase 3
- Enrollment
- 327 participants, actual
- Lead sponsor
- XenoPort, Inc.
- Conditions
- Restless Legs Syndrome
- Interventions
- GEn (XP13512), GEn (XP13512), Placebo
- First posted
- 2006-04-05
- Last updated
- 2013-07-22
- Results first posted
- 2011-05-25
Source ClinicalTrials.gov
Registered outcomes33
Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.
| List | Outcome | Time frame | Description |
|---|---|---|---|
| Primary | Percentage of Participants Who Experienced a Relapse During the Double-Blind Treatment Period | DB Treatment Period; Days 169 to 252 (Weeks 24 to 36) | Relapse was defined as worsening of Restless Legs Syndrome (RLS) symptoms or withdrawal due to lack of efficacy during the 12-week double-blind (DB) treatment period (the period from Randomization on Visit 14 \[Week 24\] through the end of treatment). Worsening of symptoms was defined as an increase in the total International RLS (IRLS) Scale score by at least 6 or more points relative to the participant's score at Randomization, achieving an IRLS score of at least 15, and an assessment of "much worse" or "very much worse" on the investigator-rated Clinical Global Impression of Change (CGI-C). |
| Secondary | Time From Randomization to Relapse in RLS Symptoms During the Double-Blind Treatment Period | DB Treatment Period; Days 169 to 252 (Weeks 24 to 36) | Time to relapse was defined as the time until worsening of Restless Legs Syndrome (RLS) symptoms or withdrawal due to lack of efficacy during the 12-week Double-blind (DB) treatment period (same as primary outcome definition). Note: The median is not estimable with Kaplan-Meier methodology when fewer than 50% of participants experience an event. The median is not estimable for this outcome. |
| Secondary | Time From Randomization to Relapse in RLS Symptoms During the Double-Blind Treatment Period (Excluding First Two Weeks of DB Phase) | DB Treatment Period; Days 184 to 252 (Weeks 26 to 36) | Time to relapse was defined as the time until worsening of Restless Legs Syndrome (RLS) symptoms or withdrawal due to lack of efficacy during the 12-week Double-blind (DB) treatment period (same as primary outcome definition). Note: The median is not estimable with Kaplan-Meier methodology when fewer than 50% of participants experience an event. The median is not estimable for this outcome. |
| Secondary | Mean Change From Randomization to Week 36 (or End of Treatment) in the IRLS Rating Scale (IRLS) Total Score Using Last Observation Carried Forward (LOCF) | Randomization (Week 24) and Week 36 (or end of DB treatment) | The IRLS Rating scale is a measure of RLS disease severity and reflects the participant-reported assessment of primary sensory and motor features and associated sleep problems in RLS. Items are included that assess the impact of symptoms on participants' mood, daily life, and activities. The total score ranges from 0-40 points, with 40 being the most severe. The scale assesses symptoms over the week prior to measurement. LOCF: Missing data (MD) values were imputed using the last non-missing observation prior to the visit with MD; randomization visit data could be carried forward. |
| Secondary | Percentage of Participants Who Responded to Treatment Based on Scores on the Investigator-Rated Clinical Global Impression of Change (CGI-C) Scale as a Dichotomous Variable at Week 36 (DB Treatment Phase) Using LOCF | Randomization (Week 24) and Week 36 (or end of DB treatment) | The CGI-C scale 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 baseline. For this endpoint, "response" on the CGI-C was defined as participants with a rating of "no change," (score of 4) "minimally improved," (score of 3) "much improved," (score of 2) or "very much improved" (score of 1) compared to Randomization (Week 24). |
| Secondary | Number of Participants in Each Category of the Investigator-Rated CGI-C at Week 36 (DB Treatment Phase) Using LOCF | Randomization (Week 24) and Week 36 (or end of DB treatment) | The CGI scale 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 baseline. |
| Secondary | Number of Participants in Each Category of the Participant-Rated CGI-I Scale at Week 36 (DB Treatment Phase) Using LOCF | Week 36 (or end of DB treatment) | The participant-rated CGI-I scale is a self-rated assessment designed to allow participants to rate the change of their disease severity over time based on a seven-point scale, with a score of 1 being "very much improved" and a score of 7 being "very much worse" compared to baseline. |
| Secondary | Percentage of Participants Who Responded to Treatment Based on Scores on the Participant-Rated CGI-I at Week 36 (DB Treatment Phase) Using LOCF | Week 36 (or end of DB treatment) | The participant-rated CGI-I scale is a self-rated assessment designed to allow participants to rate the change of their disease severity over time based on a seven-point scale, with a score of 1 being "very much improved," and a score of 7 being "very much worse." Response on the participant-rated CGI-I was defined as a rating of "very much improved" (score of 1) or "much improved" (score of 2) compared to Baseline of the SB phase. |
| Secondary | Mean Change From Randomization to Week 36 (DB Treatment Phase) in the Mean Daytime Somnolence Domain Score of the Medical Outcomes Study (MOS) Sleep Scale Using LOCF | Randomization (Week 24) and Week 36 (or end of DB treatment) | The MOS Sleep Scale is a participant-rated non-disease-specific measure with questions relating to four areas related to sleep: quantity (hours slept), sleep disturbance, sleep adequacy, and daytime somnolence. Responses are recoded so that a higher score reflects more of the attribute, and then converted to a 0 to 100 scale. The daytime somnolence score is based on questions pertaining to feeling drowsy or sleepy, trouble staying awake, and taking naps \> 5 minutes. For daytime somnolence, a negative value indicates an improvement. |
| Secondary | Mean Change From Randomization to Week 36 (DB Treatment Phase) in the Mean Sleep Disturbance Domain Score of the MOS Sleep Scale Using LOCF | Randomization (Week 24) and Week 36 (or end of DB treatment) | The MOS Sleep Scale is a participant-rated non-disease-specific measure with questions relating to four areas related to sleep: quantity (number of hours slept), sleep disturbance, sleep adequacy, and daytime somnolence. The MOS Sleep Scale sleep disturbance domain is a participant-rated measure of sleep disturbance over the month prior to the measurement. Questions are scored, and responses are converted to a 0 to 100 scale, with lower scores representing less sleep disturbance. |
1 to 10 of 33Source ClinicalTrials.gov
See all 33 registered outcomesOutcomes33
Each outcome the trial posted results for, in ClinicalTrials.gov's words.
| Type | Outcome | Time frame | Population | Units | Measured as |
|---|---|---|---|---|---|
| PRIMARY | Percentage of Participants Who Experienced a Relapse During the Double-Blind Treatment Period | DB Treatment Period; Days 169 to 252 (Weeks 24 to 36) | Double-blind Intent-to-Treat (DB ITT) Population: all participants who were randomized into the study, received at least one dose (or any portion of dose) of DB study drug, and for whom at least one post-Randomization visit (Week 24) IRLS Scale total score and investigator-rated CGI-C was available. One participant did not satisfy this description. | percentage of participants | NUMBER |
| SECONDARY | Time From Randomization to Relapse in RLS Symptoms During the Double-Blind Treatment Period | DB Treatment Period; Days 169 to 252 (Weeks 24 to 36) | DB ITT Population | ||
| SECONDARY | Time From Randomization to Relapse in RLS Symptoms During the Double-Blind Treatment Period (Excluding First Two Weeks of DB Phase) | DB Treatment Period; Days 184 to 252 (Weeks 26 to 36) | DB ITT Population | ||
| SECONDARY | Mean Change From Randomization to Week 36 (or End of Treatment) in the IRLS Rating Scale (IRLS) Total Score Using Last Observation Carried Forward (LOCF) | Randomization (Week 24) and Week 36 (or end of DB treatment) | Double-blind Intent-to-Treat (DB ITT) Population: all participants who were randomized into the study, received at least one dose (or any portion of dose) of DB study drug, and for whom at least one post-Randomization visit (Week 24) IRLS Scale total score and investigator-rated CGI-C was available. One participant did not satisfy this description. | points on a scale | MEAN |
| SECONDARY | Percentage of Participants Who Responded to Treatment Based on Scores on the Investigator-Rated Clinical Global Impression of Change (CGI-C) Scale as a Dichotomous Variable at Week 36 (DB Treatment Phase) Using LOCF | Randomization (Week 24) and Week 36 (or end of DB treatment) | Double-blind Intent-to-Treat (DB ITT) Population: all participants who were randomized into the study, received at least one dose (or any portion of dose) of DB study drug, and for whom at least one post-Randomization visit (Week 24) IRLS Scale total score and investigator-rated CGI-C was available. One participant did not satisfy this description. | percentage of participants | NUMBER |
| SECONDARY | Number of Participants in Each Category of the Investigator-Rated CGI-C at Week 36 (DB Treatment Phase) Using LOCF | Randomization (Week 24) and Week 36 (or end of DB treatment) | Double-blind Intent-to-Treat (DB ITT) Population: all participants who were randomized into the study, received at least one dose (or any portion of dose) of DB study drug, and for whom at least one post-Randomization visit (Week 24) IRLS Scale total score and investigator-rated CGI-C was available. One participant did not satisfy this description. | participants | NUMBER |
| SECONDARY | Number of Participants in Each Category of the Participant-Rated CGI-I Scale at Week 36 (DB Treatment Phase) Using LOCF | Week 36 (or end of DB treatment) | Double-blind Intent-to-Treat (DB ITT) Population: all participants who were randomized into the study, received at least one dose (or any portion of dose) of DB study drug, and for whom at least one post-Randomization visit (Week 24) IRLS Scale total score and investigator-rated CGI-C was available. One participant did not satisfy this description. | participants | NUMBER |
| SECONDARY | Percentage of Participants Who Responded to Treatment Based on Scores on the Participant-Rated CGI-I at Week 36 (DB Treatment Phase) Using LOCF | Week 36 (or end of DB treatment) | Double-blind Intent-to-Treat (DB ITT) Population: all participants who were randomized into the study, received at least one dose (or any portion of dose) of DB study drug, and for whom at least one post-Randomization visit (Week 24) IRLS Scale total score and investigator-rated CGI-C was available. One participant did not satisfy this description. | percentage of participants | NUMBER |
| SECONDARY | Mean Change From Randomization to Week 36 (DB Treatment Phase) in the Mean Daytime Somnolence Domain Score of the Medical Outcomes Study (MOS) Sleep Scale Using LOCF | Randomization (Week 24) and Week 36 (or end of DB treatment) | Double-blind Intent-to-Treat (DB ITT) Population: all participants who were randomized into the study, received at least one dose (or any portion of dose) of DB study drug, and for whom at least one post-Randomization visit (Week 24) IRLS Scale total score and investigator-rated CGI-C was available. One participant did not satisfy this description. | points on a scale | MEAN |
| SECONDARY | Mean Change From Randomization to Week 36 (DB Treatment Phase) in the Mean Sleep Disturbance Domain Score of the MOS Sleep Scale Using LOCF | Randomization (Week 24) and Week 36 (or end of DB treatment) | Double-blind Intent-to-Treat (DB ITT) Population: all participants who were randomized into the study, received at least one dose (or any portion of dose) of DB study drug, and for whom at least one post-Randomization visit (Week 24) IRLS Scale total score and investigator-rated CGI-C was available. One participant did not satisfy this description. | points on a scale | MEAN |
1 to 10 of 33Source ClinicalTrials.gov
See all 33 outcomesResults by group247
Each measurement the trial posted, group by group, in the words and numbers it posted.
| Outcome | Group | Category | Value | Spread | Units |
|---|---|---|---|---|---|
| Percentage of Participants Who Experienced a Relapse During the Double-Blind Treatment Period | DB Placebo | 22.7 | percentage of participants | ||
| Percentage of Participants Who Experienced a Relapse During the Double-Blind Treatment Period | DB GEn 1200 mg | 9.4 | percentage of participants | ||
| Mean Change From Randomization to Week 36 (or End of Treatment) in the IRLS Rating Scale (IRLS) Total Score Using Last Observation Carried Forward (LOCF) | DB Placebo | Randomization | 5.3 | Standard Deviation 4.63 | points on a scale |
| Mean Change From Randomization to Week 36 (or End of Treatment) in the IRLS Rating Scale (IRLS) Total Score Using Last Observation Carried Forward (LOCF) | DB GEn 1200 mg | Randomization | 5.1 | Standard Deviation 4.20 | points on a scale |
| Mean Change From Randomization to Week 36 (or End of Treatment) in the IRLS Rating Scale (IRLS) Total Score Using Last Observation Carried Forward (LOCF) | DB Placebo | Week 36 | 9.2 | Standard Deviation 6.76 | points on a scale |
| Mean Change From Randomization to Week 36 (or End of Treatment) in the IRLS Rating Scale (IRLS) Total Score Using Last Observation Carried Forward (LOCF) | DB GEn 1200 mg | Week 36 | 7.0 | Standard Deviation 7.47 | points on a scale |
| Mean Change From Randomization to Week 36 (or End of Treatment) in the IRLS Rating Scale (IRLS) Total Score Using Last Observation Carried Forward (LOCF) | DB Placebo | Mean change from Randomization to Week 36 | 3.9 | Standard Deviation 6.49 | points on a scale |
| Mean Change From Randomization to Week 36 (or End of Treatment) in the IRLS Rating Scale (IRLS) Total Score Using Last Observation Carried Forward (LOCF) | DB GEn 1200 mg | Mean change from Randomization to Week 36 | 1.9 | Standard Deviation 7.01 | points on a scale |
Percentage of Participants Who Responded to Treatment Based on Scores on the Investigator-Rated Clinical Global Impression of Change (CGI-C) Scale as a Dichotomous Variable at Week 36 (DB Treatment Phase) Using LOCF | DB Placebo | 67 | percentage of participants | ||
Percentage of Participants Who Responded to Treatment Based on Scores on the Investigator-Rated Clinical Global Impression of Change (CGI-C) Scale as a Dichotomous Variable at Week 36 (DB Treatment Phase) Using LOCF | DB GEn 1200 mg | 75 | percentage of participants |
1 to 10 of 247Source ClinicalTrials.gov
See all 247 results by groupParticipant flow18
How many started, completed or left each group, period by period.
| Period | Milestone | Group | Participants | Units counted |
|---|---|---|---|---|
| 24-Week Single-Blind Treatment Period | STARTED | Single-blind (SB) GEn 1200 mg | 327 | |
| 24-Week Single-Blind Treatment Period | STARTED | DB Placebo | 0 | |
| 24-Week Single-Blind Treatment Period | STARTED | DB GEn 1200 mg | 0 | |
| 24-Week Single-Blind Treatment Period | COMPLETED | Single-blind (SB) GEn 1200 mg | 221 | |
| 24-Week Single-Blind Treatment Period | COMPLETED | DB Placebo | 0 | |
| 24-Week Single-Blind Treatment Period | COMPLETED | DB GEn 1200 mg | 0 | |
| 24-Week Single-Blind Treatment Period | NOT COMPLETED | Single-blind (SB) GEn 1200 mg | 106 | |
| 24-Week Single-Blind Treatment Period | NOT COMPLETED | DB Placebo | 0 | |
| 24-Week Single-Blind Treatment Period | NOT COMPLETED | DB GEn 1200 mg | 0 | |
| 12-Week Double-Blind Treatment Period | STARTED | Single-blind (SB) GEn 1200 mg | 0 |
1 to 10 of 18Source ClinicalTrials.gov
See all 18 participant flowAdverse events36
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 | Events |
|---|---|---|---|---|---|---|
| other | Somnolence | Nervous system disorders | SB GEn 1200 mg | 97 | 326 | 97 |
| other | Somnolence | Nervous system disorders | DB Placebo | 1 | 98 | 1 |
| other | Somnolence | Nervous system disorders | DB GEn 1200 mg | 3 | 96 | 3 |
| other | Dizziness | Nervous system disorders | SB GEn 1200 mg | 72 | 326 | 72 |
| other | Dizziness | Nervous system disorders | DB Placebo | 1 | 98 | 1 |
| other | Dizziness | Nervous system disorders | DB GEn 1200 mg | 2 | 96 | 2 |
| other | Headache | Nervous system disorders | SB GEn 1200 mg | 41 | 326 | 41 |
| other | Headache | Nervous system disorders | DB Placebo | 2 | 98 | 2 |
| other | Headache | Nervous system disorders | DB GEn 1200 mg | 4 | 96 | 4 |
| other | Nasopharyngitis | Infections and infestations | SB GEn 1200 mg | 29 | 326 | 29 |
1 to 10 of 36Source ClinicalTrials.gov
See all 36 adverse eventsAdverse event totals9
The totals the trial posted for each group.
| Total | Group | Affected | At risk |
|---|---|---|---|
| Total, all-cause mortality | SB GEn 1200 mg | ||
| Total, all-cause mortality | DB Placebo | ||
| Total, all-cause mortality | DB GEn 1200 mg | ||
| Total, other adverse events | SB GEn 1200 mg | 179 | 326 |
| Total, other adverse events | DB Placebo | 15 | 98 |
| Total, other adverse events | DB GEn 1200 mg | 13 | 96 |
| Total, serious adverse events | SB GEn 1200 mg | 3 | 326 |
| Total, serious adverse events | DB Placebo | 2 | 98 |
| Total, serious adverse events | DB GEn 1200 mg | 1 | 96 |
Source ClinicalTrials.gov
Papers1
The papers the trial lists on ClinicalTrials.gov.
| PMID | Listed as |
|---|---|
| 20511481 | BACKGROUND |
Source PubMed
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.
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.
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