Clinical trial NCT00311363: Long-Term Study of Gabapentin Enacarbil (GEn, XP13512) vs. Placebo in Patients With Restless Legs Syndrome.
Official title: A Long-Term Study of XP13512 Versus Placebo Treatment Assessing Maintenance of Efficacy and Safety in Patients With Restless Legs Syndrome.
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE3
Conditions: Restless Legs Syndrome
Lead sponsor: XenoPort, Inc.
Sponsor class: INDUSTRY
First posted: 2006-04-05
Enrollment: 327
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: The primary objective of this trial is to assess the maintenance of efficacy of gabapentin enacarbil (GEn, XP13512) taken once daily in the long-term treatment of patients suffering from Restless Legs Syndrome (RLS).

Detailed description: This study was a multicenter, blinded, randomized withdrawal study in subjects with primary Restless Legs Syndrome (RLS). Eligible subjects were initially enrolled in a 24-week single blind (SB) treatment period during which they received XP13512. Subjects who completed the initial treatment period and met the responder criteria were then randomized 1:1 to receive either XP13512 or placebo during the 12-week double-blind (DB) treatment period. The primary study objective was to assess the maintenance of efficacy of XP13512 1200 mg taken once daily in the long-term treatment of subjects with primary RLS. The secondary study objectives were to assess maintenance of improvements in sleep outcomes and quality of life, and to assess the safety and tolerability of XP13512 in the treatment of primary RLS subjects.

Eligibility criteria: Inclusion Criteria:

* Patients with primary RLS, based on the International RLS Study Group Diagnostic Criteria.

Exclusion Criteria:

* A sleep disorder (e.g., sleep apnea) that may significantly affect the assessment of RLS;
* Neurologic disease or movement disorder (e.g., diabetic neuropathy, Parkinson's disease, Multiple Sclerosis, dyskinesias, and dystonias);
* Abnormal laboratory results, electrocardiogram (ECG) or physical findings;
* Pregnant or lactating women;
* Women of childbearing potential who are not practicing an acceptable method of birth control.

Primary outcomes:
measure: Percentage of Participants Who Experienced a Relapse During the Double-Blind Treatment Period
timeFrame: DB Treatment Period; Days 169 to 252 (Weeks 24 to 36)
Secondary outcomes:
measure: Time From Randomization to Relapse in RLS Symptoms During the Double-Blind Treatment Period
timeFrame: DB Treatment Period; Days 169 to 252 (Weeks 24 to 36)
measure: Time From Randomization to Relapse in RLS Symptoms During the Double-Blind Treatment Period (Excluding First Two Weeks of DB Phase)
timeFrame: DB Treatment Period; Days 184 to 252 (Weeks 26 to 36)
measure: 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)
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: 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
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: Number of Participants in Each Category of the Investigator-Rated CGI-C at Week 36 (DB Treatment Phase) Using LOCF
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: Number of Participants in Each Category of the Participant-Rated CGI-I Scale at Week 36 (DB Treatment Phase) Using LOCF
timeFrame: Week 36 (or end of DB treatment)
measure: Percentage of Participants Who Responded to Treatment Based on Scores on the Participant-Rated CGI-I at Week 36 (DB Treatment Phase) Using LOCF
timeFrame: Week 36 (or end of DB treatment)
measure: 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
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: Mean Change From Randomization to Week 36 (DB Treatment Phase) in the Mean Sleep Disturbance Domain Score of the MOS Sleep Scale Using LOCF
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: Change From Randomization to Week 36 (DB Treatment Phase) in the Mean Sleep Adequacy Domain Score of the MOS Sleep Scale Using LOCF
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: Change From Randomization to Week 36 (DB Treatment Phase) in the Mean Sleep Quantity Domain Score of the MOS Sleep Scale Using LOCF
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: Change From Randomization to Week 36 (DB Treatment Phase) in the RLS Quality of Life (QoL) Overall Life-Impact Score
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: Number of Participants With no Reported RLS Symptoms (Sx) During Each of the 4-hour Periods From the 24-hour RLS Record at Week 36 (DB Treatment Phase)
timeFrame: Week 36 (or end of DB treatment)
measure: Median Time to Onset of First RLS Symptoms Using the 24-hour RLS Symptom Record at Week 36 (DB Treatment Phase)
timeFrame: Week 36 (or end of DB treatment)
measure: Number of Participants With the Indicated Post-Sleep Questionnaire (PSQ) Responses to the Question Regarding Their Overall Quality of Sleep in the Week Prior to Measurement at Randomization and Week 36 (DB Treatment Phase) Using LOCF
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: Number of Participants With the Indicated Post-Sleep Questionnaire (PSQ) Responses to the Question Regarding Their Ability to Function in the Week Prior to Measurement at Randomization and Week 36 (DB Treatment Phase) Using LOCF
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: Number of Participants With the Indicated Post-Sleep Questionnaire Responses to the Question Regarding the Number of Nights With RLS Symptoms in the Week Prior to Measurement at Randomization and Week 36 (DB Treatment Phase) Using LOCF
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: Number of Participants With the Indicated Post-Sleep Questionnaire Responses to the Question Regarding the Number of Awakenings During Night Due to RLS Symptoms in the Week Prior to Measurement at Randomization and Week 36 (DB Treatment Phase) Using LOCF
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: Number of Participants With the Indicated Post-Sleep Questionnaire Responses to the Question Regarding the Number of Hours Awake Per Night Due to RLS Symptoms in the Week Prior to Measurement at Randomization and Week 36 (DB Treatment Phase) Using LOCF
timeFrame: Randomization (Week 24) and Week 36 (or end of DB treatment)
measure: Mean Change From Baseline in the IRLS Scale Total Score at Week 24 (SB Treatment Phase) Using LOCF
timeFrame: Days 1 to 168 (Baseline to Week 24 of SB Phase)
measure: Number of Participants in Each Category of the Investigator-Rated CGI-I at Week 24/End of Treatment (SB Treatment Phase) Using LOCF
timeFrame: Baseline and Day 168 or Week 24/End of Treatment of SB Treatment Phase
measure: Number of Participants in Each Category of the Participant-Rated CGI-I at Week 24/End of Treatment (SB Treatment Phase) Using LOCF
timeFrame: Baseline and Day 168 or Week 24/End of Treatment of SB Treatment Phase
measure: Mean Change From Baseline to Week 24 (SB Treatment Period) in the Mean Daytime Somnolence Domain Score of the Medical Outcomes Study (MOS) Sleep Scale Using LOCF
timeFrame: Baseline and Day 168 or Week 24/End of Treatment of SB Treatment Phase
measure: Mean Change From Baseline to Week 24 (SB Treatment Period) in the Mean Sleep Disturbance Domain Score of the MOS Sleep Scale Using LOCF
timeFrame: Baseline and Day 168 or Week 24/End of Treatment of SB Treatment Phase
measure: Mean Change From Baseline to Week 24 (SB Treatment Period) in the Mean Sleep Adequacy Domain Score of the MOS Sleep Scale Using LOCF
timeFrame: Baseline and Day 168 or Week 24/End of Treatment of SB Treatment Phase
measure: Mean Change From Baseline in the MOS Sleep Scale Domain, Sleep Quantity, Score at Week 24 (SB Treatment Period) Using LOCF
timeFrame: Baseline and Day 168 or Week 24/End of Treatment of SB Treatment Phase
measure: Mean Change From Baseline in the Overall Quality of Life Impact Score of the RLS Quality of Life (QoL) Questionnaire at Week 24 (SB Treatment Phase)
timeFrame: Baseline and Day 168 or Week 24/End of Treatment of SB Treatment Phase
measure: Number of Participants With the Indicated Post-Sleep Questionnaire Responses to the Question Regarding the Overall Quality of Sleep in the Week Prior to Measurement at Baseline and Week 24 (SB Treatment Period) Using LOCF
timeFrame: Baseline and Day 168 or Week 24/End of Treatment of SB Treatment Phase
measure: Number of Participants With the Indicated Post-Sleep Questionnaire Responses to the Question Regarding the Ability to Function in the Week Prior to Measurement at Baseline and Week 24 (SB Treatment Period) Using LOCF
timeFrame: Baseline and Day 168 or Week 24/End of Treatment of SB Treatment Phase
measure: Number of Participants With the Indicated Post-Sleep Questionnaire Responses to the Question Regarding the Number of Nights With RLS Symptoms in the Week Prior to Measurement at Baseline and Week 24 (SB Treatment Period) Using LOCF
timeFrame: Baseline and Day 168 or Week 24/End of Treatment of SB Treatment Phase
measure: Number of Participants With the Indicated Post-Sleep Questionnaire Responses to the Question Regarding the Number of Awakenings During the Night Due to RLS Symptoms in the Week Prior to Measurement at Baseline and Week 24 (SB Treatment Period) Using LOCF
timeFrame: Baseline and Day 168 or Week 24/End of Treatment of SB Treatment Phase
measure: Number of Participants With the Indicated Post-Sleep Questionnaire Responses to the Question Regarding the Number of Hours Awake Per Night Due to RLS Symptoms in the Week Prior to Measurement at Baseline and Week 24 (SB Treatment Period) Using LOCF
timeFrame: Baseline and Day 168 or Week 24/End of Treatment of SB Treatment Phase
Other outcomes:
Locations:
Study officials:
affiliation: GlaxoSmithKline
name: GSK Clinical Trials
role: STUDY_DIRECTOR
References:
citation: Bogan RK, Bornemann MA, Kushida CA, Tran PV, Barrett RW; XP060 Study Group. Long-term maintenance treatment of restless legs syndrome with gabapentin enacarbil: a randomized controlled study. Mayo Clin Proc. 2010 Jun;85(6):512-21. doi: 10.4065/mcp.2009.0700.