Trial Outcomes & Findings for A Clinical Study in Subjects With Neuropathic Pain From PHN Who Have Had an Inadequate Response to Gabapentin Treatment (NCT NCT00617461)

NCT ID: NCT00617461

Last Updated: 2013-07-22

Results Overview

Baseline and end of treatment values are the calculated means of the daily 24-hour API scores for each participant during the last 7 days prior to randomization (baseline) and the last 7 days on treatment within each period (end of treatment). Participants rated their API over the preceding 24 hours, using an 11-point PI-Numerical Rating Scale (0=no pain, 10=pain as bad as you can imagine). LOCF was used if less than 4 days of diary data were provided. Change from baseline was calculated as end of treatment minus baseline. Data are summarized by dose, independent of treatment period.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

96 participants

Primary outcome timeframe

Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Results posted on

2013-07-22

Participant Flow

Participants (par.) were enrolled in a two-week Baseline Period, which included treatment with 1800 milligrams (mg)/day gabapentin. Participants who met entry criteria were then randomized. Inv., investigator.

Participant milestones

Participant milestones
Measure
GEn 1200 mg/Day Followed by GEn 3600 mg/Day
Gabapentin enacarbil (XP13512/GSK1838262), hereafter referred to as GEn, 1200 mg/day administered for 28 days, followed by a 4-day crossover period during which participants received GEn 2400 mg/day. After the crossover period, participants switched to a dose of 3600 mg/day for 28 days. After completion of the second treatment period, participants entered a down-titration period in which they received 1200 mg/day for 3 days, followed by 600 mg/ day for 3 days.
GEn 3600 mg/Day Followed by GEn 1200 mg/Day
GEn 3600 mg/day administered for 28 days, followed by a 4-day crossover period during which participants received GEn 2400 mg/day. After the crossover period, participants switched to a dose of 1200 mg/day for 28 days. After completion of the second treatment period, participants entered a down-titration period in which they received 2400 mg/day for 2 days, followed by 1200 mg/day for 2 days, followed by 600 mg/day for 2 days.
First Treatment Intervention Period
STARTED
52
44
First Treatment Intervention Period
COMPLETED
42
41
First Treatment Intervention Period
NOT COMPLETED
10
3
4-Day Crossover Period
STARTED
42
40
4-Day Crossover Period
COMPLETED
41
40
4-Day Crossover Period
NOT COMPLETED
1
0
Second Treatment Intervention Period
STARTED
41
41
Second Treatment Intervention Period
COMPLETED
41
37
Second Treatment Intervention Period
NOT COMPLETED
0
4
6-Day Down-Titration Period
STARTED
41
37
6-Day Down-Titration Period
COMPLETED
39
35
6-Day Down-Titration Period
NOT COMPLETED
2
2

Reasons for withdrawal

Reasons for withdrawal
Measure
GEn 1200 mg/Day Followed by GEn 3600 mg/Day
Gabapentin enacarbil (XP13512/GSK1838262), hereafter referred to as GEn, 1200 mg/day administered for 28 days, followed by a 4-day crossover period during which participants received GEn 2400 mg/day. After the crossover period, participants switched to a dose of 3600 mg/day for 28 days. After completion of the second treatment period, participants entered a down-titration period in which they received 1200 mg/day for 3 days, followed by 600 mg/ day for 3 days.
GEn 3600 mg/Day Followed by GEn 1200 mg/Day
GEn 3600 mg/day administered for 28 days, followed by a 4-day crossover period during which participants received GEn 2400 mg/day. After the crossover period, participants switched to a dose of 1200 mg/day for 28 days. After completion of the second treatment period, participants entered a down-titration period in which they received 2400 mg/day for 2 days, followed by 1200 mg/day for 2 days, followed by 600 mg/day for 2 days.
First Treatment Intervention Period
Adverse Event
2
0
First Treatment Intervention Period
Lack of Efficacy
1
0
First Treatment Intervention Period
Protocol Violation
2
1
First Treatment Intervention Period
Lost to Follow-up
0
1
First Treatment Intervention Period
Investigator Discretion
1
1
First Treatment Intervention Period
Withdrawal by Subject
4
0
4-Day Crossover Period
Withdrawal by Subject
1
0
Second Treatment Intervention Period
Adverse Event
0
1
Second Treatment Intervention Period
Lack of Efficacy
0
3
6-Day Down-Titration Period
Withdrawal by Subject
1
0
6-Day Down-Titration Period
Did Not Attend Down-titration Visit
1
2

Baseline Characteristics

A Clinical Study in Subjects With Neuropathic Pain From PHN Who Have Had an Inadequate Response to Gabapentin Treatment

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
All Participants in the Intent-to-Treat Population
n=93 Participants
All randomized participants who took at least one dose of study drug and had at least one post-baseline efficacy assessment, summarized independent of treatment sequence.
Age Continuous
63 Years
STANDARD_DEVIATION 12.15 • n=5 Participants
Sex: Female, Male
Female
36 Participants
n=5 Participants
Sex: Female, Male
Male
57 Participants
n=5 Participants
Race/Ethnicity, Customized
African American/African Heritage
18 participants
n=5 Participants
Race/Ethnicity, Customized
White
74 participants
n=5 Participants
Race/Ethnicity, Customized
American Indian or Alaska Native & White
1 participants
n=5 Participants

PRIMARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: Of the 93 participants in the ITT Population, there were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. In addition, 1 participant did not provide post-baseline data for 24-hour API assessments during the GEn 3600mg treatment period, and was therefore not included in this analysis.

Baseline and end of treatment values are the calculated means of the daily 24-hour API scores for each participant during the last 7 days prior to randomization (baseline) and the last 7 days on treatment within each period (end of treatment). Participants rated their API over the preceding 24 hours, using an 11-point PI-Numerical Rating Scale (0=no pain, 10=pain as bad as you can imagine). LOCF was used if less than 4 days of diary data were provided. Change from baseline was calculated as end of treatment minus baseline. Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=90 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=84 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Change From Baseline in the Mean 24-hour Average Pain Intensity (API) Score at the Last Week of Each Treatment Period Using Last Observation Carried Forward (LOCF) Data
-1.18 points on a scale
Standard Error 0.171
-1.47 points on a scale
Standard Error 0.173

PRIMARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: Of the 93 participants in the ITT Population, there were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. In addition, 1 participant did not provide post-baseline data for 24 hour API while taking GEn 3600 mg in the first period, and was therefore not included in this analysis.

Baseline and end of treatment values are the calculated means of the daily 24-hour API scores for each participant during the last 7 days prior to randomization (baseline) and the last 7 days on treatment within each period (end of treatment). Participants used a hand-held diary to rate their average pain intensity over the preceding 24 hours, using an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). LOCF was used if less than 4 days of diary data were provided. The by period summary is provided as a sensitivity analysis for the primary analysis.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=49 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=43 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
n=41 Participants
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
n=41 Participants
GEn 3600 mg daily in second intervention period only
Change From Baseline in the Mean 24-hour Average Pain Intensity (API) Score at the Last Week of Each Treatment Period Using LOCF Data for Each Treatment Period
-1.11 points on a scale
Standard Deviation 1.477
-1.09 points on a scale
Standard Deviation 1.366
-1.29 points on a scale
Standard Deviation 1.742
-1.92 points on a scale
Standard Deviation 2.000

SECONDARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: Of the 93 participants in the ITT Population, there were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. In addition, 1 participant did not provide post-baseline data for day-time pain assessments during the GEn 3600 mg treatment period, and was therefore not included in this analysis.

Day-time is defined as the time between rising in the morning and going to bed at night. Participants recorded day-time API on a daily basis in the evening before bedtime using an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). Baseline and end of treatment scores are as defined for the primary endpoint. Change from baseline is calculated as the end of treatment score minus the baseline score. An ANCOVA with baseline value, BMI, grouped center as covariates was used. Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=90 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=84 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Change From Baseline in the Mean Day-time Average Pain Intensity (API) Score at the Last Week of Each Treatment Period Using LOCF Data
-1.17 points on a scale
Standard Error 0.172
-1.48 points on a scale
Standard Error 0.174

SECONDARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: Of the 93 participants in the ITT Population, there were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. In addition, 1 participant did not provide post-baseline data for day-time pain assessments during the GEn 3600 mg treatment period, and was therefore not included in this analysis.

Day-time worst pain is defined as the participant's assessment of their worst pain intensity between rising in the morning and going to bed at night. Day-time worst pain was recorded in the evening before bedtime using an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). Baseline and end of treatment scores are as defined for the primary endpoint. Change from baseline is calculated as the end of treatment score minus the baseline score. An ANCOVA with baseline value, BMI, grouped center as covariates was used. Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=90 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=84 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Change From Baseline in the Mean Day-time Worst Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
-1.17 points on a scale
Standard Error 0.178
-1.50 points on a scale
Standard Error 0.181

SECONDARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: Of the 93 participants in the ITT Population, there were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. In addition, 1 participant did not provide post-baseline data for current evening pain during the GEn 3600 mg treatment period, and was therefore not included in this analysis.

Current pain is defined as the participant's assessment of pain intensity "right now." Participants recorded their current evening pain intensity in the evening before bedtime using an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). Baseline and end of treatment scores are as defined for the primary endpoint. Change from baseline is calculated as the end of treatment score minus the baseline score. An ANCOVA with baseline value, BMI, grouped center as covariates was used. Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=90 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=84 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Change From Baseline in the Mean Current (Evening) Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
-1.10 points on a scale
Standard Error 0.180
-1.39 points on a scale
Standard Error 0.183

SECONDARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: Of the 93 participants in the ITT Population, there were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. In addition, 1 participant did not provide post-baseline data for night-time pain assessments during the GEn 1200 mg treatment period, and was therefore not included in this analysis.

Night-time is defined as the time between going to bed in the evening and rising in the morning. Participants recorded night-time API on a daily basis in the morning upon wakening using an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). Baseline and end of treatment scores are as defined for the primary endpoint. Change from baseline is calculated as the end of treatment score minus the baseline score. An ANCOVA with baseline value, BMI, grouped center as covariates was used. Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=89 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=85 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Change From Baseline in the Mean Night-time Average Pain Intensity (API) Score at the Last Week of Each Treatment Period Using LOCF
-0.92 points on a scale
Standard Error 0.188
-1.21 points on a scale
Standard Error 0.190

SECONDARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: Of the 93 participants in the ITT Population, there were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. In addition, 1 participant did not provide post-baseline data for night-time pain assessments during the GEn 1200 mg treatment period, and was therefore not included in this analysis.

Night-time worst pain is defined as the participant's assessment of their worst pain intensity between going to bed and rising in the morning. Participants recorded night-time worst pain in the morning upon wakening using an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). Baseline and end of treatment scores are as defined for primary endpoint. Change from baseline = the end of treatment score minus the baseline score. An ANCOVA with baseline value, BMI, grouped center as covariates was used. Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=89 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=85 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Change From Baseline in the Mean Night-time Worst Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF
-0.97 points on a scale
Standard Error 0.192
-1.33 points on a scale
Standard Error 0.194

SECONDARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: Of the 93 participants in the ITT Population, there were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. In addition, 1 participant did not provide post-baseline data for current morning pain during the GEn 1200 mg treatment period, and was therefore not included in this analysis.

Current pain is defined as the participant's assessment of pain intensity "right now." Participants recorded their current morning pain intensity in the morning upon wakening using an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). Baseline and end of treatment scores are as defined for the primary endpoint. Change from baseline is calculated as the end of treatment score minus the baseline score. An ANCOVA with baseline value, BMI, grouped center as covariates was used. Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=89 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=85 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Change From Baseline in the Mean Current Morning Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF
-1.11 points on a scale
Standard Error 0.187
-1.46 points on a scale
Standard Error 0.189

SECONDARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: Of the 93 participants in the ITT Population, there were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. In addition, there was one participant who did not provide post-baseline data for 24-hour API assessments during the GEn 3600 mg treatment period, and was therefore not included in this analysis.

Baseline and end of treatment (EOT) scores are the calculated means of the 24-hour average pain scores for each participant during the last 7 days prior to randomization (Baseline) and the 7 days prior to the last on-treatment completed diary (EOT). Percent reduction from baseline was calculated as the \[(EOT score minus baseline score) divided by the baseline score\], multiplied by 100. The PI-NRS is an 11-point scale (0=no pain, 10=pain as bad as you can imagine) by which a participant assesses their 24-hour average pain intensity. Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=90 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=84 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
0% or more
68 participants
71 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
10% or more
51 participants
49 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
20% or more
39 participants
42 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
30% or more
28 participants
32 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
40% or more
17 participants
26 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
50% or more
15 participants
16 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
60% or more
6 participants
11 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
70% or more
4 participants
5 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
80% or more
1 participants
2 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
90% or more
1 participants
2 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data
100%
0 participants
2 participants

SECONDARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: Of the 93 participants in the ITT Population, there were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. In addition, there was one participant who did not provide post-baseline data for 24-hour API while taking GEn 3600 mg in the first period, and was therefore not included in this analysis.

Baseline and end of treatment scores are the calculated means of the 24-hour average pain scores for each participant during the last 7 days prior to randomization (Baseline) and the 7 days prior to the last on-treatment completed diary (end of treatment). Percent reduction from baseline was calculated as the \[(end of treatment score minus the baseline score) divided by the baseline score\], multiplied by 100. The PI-NRS is an 11-point scale (0=no pain, 10=pain as bad as you can imagine) by which a participant assesses their 24-hour average pain intensity. Data are summarized by period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=49 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=43 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
n=41 Participants
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
n=41 Participants
GEn 3600 mg daily in second intervention period only
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data by Period
100%
0 participants
0 participants
0 participants
2 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data by Period
0% or more
38 participants
34 participants
30 participants
37 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data by Period
10% or more
26 participants
23 participants
25 participants
26 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data by Period
20% or more
19 participants
19 participants
20 participants
23 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data by Period
30% or more
13 participants
13 participants
15 participants
19 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data by Period
40% or more
9 participants
10 participants
8 participants
16 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data by Period
50% or more
7 participants
5 participants
8 participants
11 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data by Period
60% or more
1 participants
3 participants
5 participants
8 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data by Period
70% or more
0 participants
0 participants
4 participants
5 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data by Period
80% or more
0 participants
0 participants
1 participants
2 participants
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at the Last Week of Each Treatment Period Using LOCF Data by Period
90% or more
0 participants
0 participants
1 participants
2 participants

SECONDARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: Of the 93 participants in the ITT Population, there were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. In addition, there was one participant who did not provide post-baseline data for rescue medication usage during the GEn 3600 mg treatment period, and was therefore not included in this analysis.

Mean daily use of rescue medication (milligrams of acetaminophen) was calculated by determining the average number of tablets taken per day of rescue medication (Commercial Tylenol) during treatment and multiplying that by 500 mg. Baseline and end of treatment scores are as defined for the primary endpoint. Change from baseline is calculated as the end of treatment score minus the baseline score. An ANCOVA with baseline value, BMI, grouped center as covariates was used. Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=90 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=84 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Change From Baseline in the Mean Daily Dose in Milligrams of Rescue Medication at the Last Week of Each Treatment Period
-68.18 milligrams
Standard Error 73.404
-71.26 milligrams
Standard Error 74.746

SECONDARY outcome

Timeframe: End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: ITT Population. There were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. There were many participants who did not respond to the questionnaire and thus could not be included in the analysis.

The PGIC is a single-item questionnaire designed to provide an overall assessment of treatment from the participant's perspective since the start of the study. It is measured on a 7-point scale, where 1=very much improved and 7=very much worse. A participant is considered a responder if they have a response of "very much improved" or "much improved" Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=63 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=61 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Number of Participants Who Are Responders on the Patient Global Impression of Change (PGIC) at the Last Week of Each Treatment Period Using LOCF Data
17 participants
28 participants

SECONDARY outcome

Timeframe: End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: ITT Population. There were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. There were many participants who did not respond to the questionnaire and thus could not be included in the analysis.

The PGIC is a single-item questionnaire designed to provide an overall assessment of treatment from the participant's perspective since the start of the study. It is measured on a 7-point scale, where 1=very much improved and 7=very much worse. A participant is considered a responder if they have a response of "very much improved" or "much improved". Data are summarized by dose within each treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=35 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=27 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
n=28 Participants
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
n=34 Participants
GEn 3600 mg daily in second intervention period only
Number of Participants Who Are Responders on the Patient Global Impression of Change (PGIC) Questionnaire at the Last Week of Each Treatment Period Presented by Period Using LOCF Data
6 participants
11 participants
11 participants
17 participants

SECONDARY outcome

Timeframe: End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: ITT Population. There were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. There were many participants without a response to this questionnaire and thus could not be included in the analysis.

The CGIC is a single-item questionnaire designed to provide an overall assessment of treatment from the clinician's perspective since the start of the study. It is measured on a 7-point scale, where 1=very much improved and 7=very much worse. A participant is considered a responder if they have a response of "very much improved" or "much improved." Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=53 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=48 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Number of Participants Who Are Responders on the Clinical Global Impression of Change (CGIC) Questionnaire at the Last Week of Each Treatment Period Using LOCF Data
15 participants
18 participants

SECONDARY outcome

Timeframe: End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: ITT Population. There were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. There were many participants without a response data to this questionnaire and could thus not be included in the analysis.

The CGIC is a single-item questionnaire designed to provide an overall assessment of treatment from the clinician's perspective since the start of the study. It is measured on a 7-point scale, where 1=very much improved and 7=very much worse. A participant is considered a responder if they have a response of "very much improved" or "much improved." Data are summarized by dose within each treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=28 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=22 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
n=25 Participants
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
n=26 Participants
GEn 3600 mg daily in second intervention period only
Number of Participants Who Are Responders on the Clinical Global Impression of Change (CGIC) Questionnaire at the Last Week of Each Treatment Period Presented by Period Using LOCF Data
5 participants
8 participants
10 participants
10 participants

SECONDARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of each treatment period)

Population: Of the 93 participants in the ITT Population, there were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. In addition, 1 participant did not provide post-baseline data for sleep interference during the GEn 1200 mg treatment period, and was therefore not included in this analysis.

Participants assessed sleep interference due to pain on a daily basis using the 11-point NRS (0=pain does not interfere with sleep, 10=pain completely interferes with sleep). Baseline and end of treatment scores are as defined for the primary endpoint. Change from baseline is calculated as the end of treatment score minus the baseline score. An ANCOVA with baseline value, BMI, grouped center as covariates was used. Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=89 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=85 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Change From Baseline in the Mean Sleep Interference Score at the Last Week of Each Treatment Period Using LOCF Data
-0.97 points on a scale
Standard Error 0.205
-1.23 points on a scale
Standard Error 0.207

SECONDARY outcome

Timeframe: Baseline and End of Treatment (Weeks 4 and 9, representing the last week of treatment)

Population: ITT Population. There were 3 and 8 participants who did not take GEn 1200 and 3600 mg, respectively, in the second period. There were many participants who did not respond to the questionnaire and could thus not be included in the analysis.

The BPI assesses the severity and interference of pain; and consists of 6 items assessed on an 11-point NRS (0=no impact to 10=greatest impact). 2 summary scores are calculated: BPI Severity Score (average of first 4 items) and BPI Interference Score (average of 7 responses to item 6); where scores range from 0 to 10 (0=no impact to 10=greatest impact). Analysis of this endpoint is based on the change from baseline (BL) (EOMT score minus the BL score) using an ANCOVA model with BL value, BMI, grouped center as covariates. Data are summarized by dose, independent of treatment period.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=62 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=60 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Change From Baseline in the Severity of Pain and the Impact of Pain as Assessed by the Brief Pain Inventory (BPI) at the Last Week of Each Treatment Period Using LOCF
Brief Pain Inventory Severity of Pain
-1.17 points on a scale
Standard Error 0.223
-1.63 points on a scale
Standard Error 0.225
Change From Baseline in the Severity of Pain and the Impact of Pain as Assessed by the Brief Pain Inventory (BPI) at the Last Week of Each Treatment Period Using LOCF
Brief Pain Inventory Interference of Pain
-0.82 points on a scale
Standard Error 0.244
-1.57 points on a scale
Standard Error 0.247

SECONDARY outcome

Timeframe: A total of 10 blood samples (2 samples at each visit) were collected per participant at Baseline, and the Week 1 and Week 4 visits for each period

Population: Drug concentration data were available from 89 ITT Population participants. Data from 7 of these participants had one concentration with less than half of the first percentile of the concentrations observed at ss and were defined as non-compliant and were excluded from the pharmacokinetic (PK) analysis.

Steady-state average (Cave, ss), maximum (Cmax, ss), and minimum (Cmin,ss) plasma concentration of gabapentin in each participant were estimated using the gabapentin plasma concentration data and with the aid of a population pharmacokinetic model. Dispersion is represented by the fifth to ninety-fifth percentile, though labeled as "Full Range." A total of 10 blood samples were collected per participant over the Baseline, Period 1, and Period 2 at various timepoints during the dosing interval. Plasma concentration of gabapentin in these samples was measured.

Outcome measures

Outcome measures
Measure
GEn 1200 mg
n=82 Participants
GEn 1200 mg daily either in first intervention period or second intervention period
GEn 3600 mg
n=82 Participants
GEn 3600 mg daily either in first intervention period or second intervention period
GEn 1200 mg in Second Intervention Period
n=82 Participants
GEn 1200 mg daily in second intervention period only
GEn 3600 mg in Second Interevention Period
GEn 3600 mg daily in second intervention period only
Mean Gabapentin Steady-State (ss) Average, Minimum and Maximum Concentrations
Cmin, ss
3.0 micrograms per milliliter
Interval 1.7 to 6.1
9.2 micrograms per milliliter
Interval 4.5 to 18.5
4.3 micrograms per milliliter
Interval 2.3 to 9.4
Mean Gabapentin Steady-State (ss) Average, Minimum and Maximum Concentrations
Cmax, ss
5.1 micrograms per milliliter
Interval 3.4 to 9.0
15.2 micrograms per milliliter
Interval 9.9 to 27.0
7.4 micrograms per milliliter
Interval 4.3 to 13.7
Mean Gabapentin Steady-State (ss) Average, Minimum and Maximum Concentrations
Cave,ss
4.1 micrograms per milliliter
Interval 2.9 to 7.4
12.4 micrograms per milliliter
Interval 8.5 to 22.2
6.8 micrograms per milliliter
Interval 3.8 to 13.4

Adverse Events

Baseline Gabapentin 1800 mg

Serious events: 0 serious events
Other events: 2 other events
Deaths: 0 deaths

GEn 1200 mg

Serious events: 0 serious events
Other events: 15 other events
Deaths: 0 deaths

Crossover GEn 2400 mg

Serious events: 0 serious events
Other events: 3 other events
Deaths: 0 deaths

GEn 3600 mg

Serious events: 0 serious events
Other events: 14 other events
Deaths: 0 deaths

Down-Titration Period

Serious events: 1 serious events
Other events: 2 other events
Deaths: 0 deaths

Overall GEn

Serious events: 1 serious events
Other events: 27 other events
Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure
Baseline Gabapentin 1800 mg
n=94 participants at risk
Gabapentin 1800 mg daily for 2 weeks before randomization. Only includes participants who were subsequently randomized.
GEn 1200 mg
n=91 participants at risk
GEn 1200 mg daily either in first intervention period or second intervention period
Crossover GEn 2400 mg
n=82 participants at risk
GEn 2400 mg daily during 4-day crossover period in between the first intervention period and the second intervention period
GEn 3600 mg
n=85 participants at risk
GEn 3600 mg daily either in first intervention period or second intervention period
Down-Titration Period
n=80 participants at risk
Participants down- titrated from GEn 3600 mg/day by taking 2400 mg/day for 2 days, followed by 1200 mg/day for 2 days, followed by 600 mg/day for 2 days before ending the assigned treatment. Participants down- titrated from GEn 1200 mg/day by taking 1200 mg/day for 3 days, followed by 600 mg/day for 3 days before ending the assigned treatment.
Overall GEn
n=94 participants at risk
All participants receiving GEn in any treatment period
Psychiatric disorders
Hallucination, auditory
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.1%
1/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.

Other adverse events

Other adverse events
Measure
Baseline Gabapentin 1800 mg
n=94 participants at risk
Gabapentin 1800 mg daily for 2 weeks before randomization. Only includes participants who were subsequently randomized.
GEn 1200 mg
n=91 participants at risk
GEn 1200 mg daily either in first intervention period or second intervention period
Crossover GEn 2400 mg
n=82 participants at risk
GEn 2400 mg daily during 4-day crossover period in between the first intervention period and the second intervention period
GEn 3600 mg
n=85 participants at risk
GEn 3600 mg daily either in first intervention period or second intervention period
Down-Titration Period
n=80 participants at risk
Participants down- titrated from GEn 3600 mg/day by taking 2400 mg/day for 2 days, followed by 1200 mg/day for 2 days, followed by 600 mg/day for 2 days before ending the assigned treatment. Participants down- titrated from GEn 1200 mg/day by taking 1200 mg/day for 3 days, followed by 600 mg/day for 3 days before ending the assigned treatment.
Overall GEn
n=94 participants at risk
All participants receiving GEn in any treatment period
Infections and infestations
Nasopharyngitis
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
4.4%
4/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
5.3%
5/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Nervous system disorders
Headache
1.1%
1/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.1%
1/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
3.5%
3/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
4.3%
4/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Nervous system disorders
Dizziness
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
3.5%
3/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
4.3%
4/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Gastrointestinal disorders
Nausea
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
3.3%
3/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
4.3%
4/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
General disorders
Fatigue
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.4%
2/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
3.2%
3/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Nervous system disorders
Post herpetic neuralgia
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
3.3%
3/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
3.2%
3/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Nervous system disorders
Somnolence
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
3.3%
3/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.4%
2/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
3.2%
3/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
General disorders
Odema peripheral
1.1%
1/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.1%
1/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.1%
2/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Investigations
Blood pressure increased
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.1%
1/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.1%
2/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Gastrointestinal disorders
Constipation
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.2%
2/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.1%
2/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Metabolism and nutrition disorders
Diabetes mellitus
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.1%
2/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Gastrointestinal disorders
Dyspepsia
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.4%
2/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.1%
2/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Metabolism and nutrition disorders
Gout
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.1%
1/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.1%
2/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
General disorders
Irritability
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.2%
2/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.1%
2/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Musculoskeletal and connective tissue disorders
Myalgia
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.1%
2/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Renal and urinary disorders
Nephrolithiasis
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.4%
2/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.1%
2/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Skin and subcutaneous tissue disorders
Rash pruritic
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.2%
2/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.1%
2/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
Infections and infestations
Sinusitis
0.00%
0/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.1%
1/91 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/82 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
1.2%
1/85 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
0.00%
0/80 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.
2.1%
2/94 • Adverse events (AEs) were collected from the start of the baseline gabapentin treatment period through the post-treatment follow-up visit (up to Week 11).
The AEs reported to start or worsen during the treatment phase of the study are presented.

Additional Information

XenoPort Call Center

XenoPort, Inc.

Phone: 877-936-6778

Results disclosure agreements

  • Principal investigator is a sponsor employee GSK agreements may vary with individual investigators, but will not prohibit any investigator from publishing. GSK supports the publication of results from all centers of a multi-center trial but requests that reports based on single-site data not precede the primary publication of the entire clinical trial.
  • Publication restrictions are in place

Restriction type: OTHER