A Study In Patients With Neuropathic Pain From Diabetic Peripheral Neuropathy (DPN) - Study Results

Study Type:	Interventional
Study Design:	Allocation: Randomized; Intervention Model: Parallel Assignment; Masking: Triple (Participant, Investigator, Outcomes Assessor); Primary Purpose: Treatment
Condition:	Neuropathy, Diabetic
Interventions:	Drug: Placebo Drug: GEn 1200mg/day Drug: GEn 2400mg/day Drug: GEn 3600mg/day Drug: Pregabalin

Participant Flow

Recruitment Details

Key information relevant to the recruitment process for the overall study, such as dates of the recruitment period and locations
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Pre-Assignment Details

Significant events and approaches for the overall study following participant enrollment, but prior to group assignment
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Reporting Groups

	Description
Placebo	Three 600 milligram (mg) gabapentin enacarbil (XP13512/GSK1838262), hereafter referred to as GEn, placebo tablets taken orally twice daily (morning and evening); one 100 mg pregabalin (PGB) placebo capsule taken orally three times daily (morning, midday, and evening).
GEn 1200 mg/Day	One 600 mg extended release (ER) GEn tablet and two 600 mg GEn placebo tablets taken orally twice daily (morning and evening); one 100 mg PGB placebo capsule taken orally three times daily (morning, midday, and evening).
GEn 2400 mg/Day	Two 600 mg ER GEn tablets and one 600 mg GEn placebo tablet taken orally twice daily (morning and evening); one 100 mg PGB placebo capsule taken orally three times daily (morning, midday, and evening).
GEn 3600 mg/Day	Three 600 mg ER GEn tablets taken orally twice daily (morning and evening); one 100 mg PGB placebo capsule taken orally three times daily (morning, midday, and evening).
PGB 300 mg/Day	Three 600 mg GEn placebo tablets taken orally twice daily (morning and evening); one 100 mg PGB capsule taken orally three times daily (morning, midday, and evening).

Participant Flow: Overall Study

	Placebo	GEn 1200 mg/Day	GEn 2400 mg/Day	GEn 3600 mg/Day	PGB 300 mg/Day
STARTED	120	62	56	117	66
Safety Population/Treated With Drug	120	62	56	116	66
ITT Population	120	62	56	116	66
COMPLETED	90	47	37	79	47
NOT COMPLETED	30	15	19	38	19
Adverse Event	11	5	12	21	6
Lack of Efficacy	3	1	0	4	3
Protocol Violation	7	6	4	4	6
Lost to Follow-up	6	2	1	3	3
Investigator Discretion	0	0	0	2	0
Withdrawal by Subject	3	1	2	4	1

Baseline Characteristics

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Population Description

Explanation of how the number of participants for analysis was determined. Includes whether analysis was per protocol, intention to treat, or another method. Also provides relevant details such as imputation technique, as appropriate.
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Reporting Groups

	Description
Placebo	Three 600 milligram (mg) gabapentin enacarbil (XP13512/GSK1838262), hereafter referred to as GEn, placebo tablets taken orally twice daily (morning and evening); one 100 mg pregabalin (PGB) placebo capsule taken orally three times daily (morning, midday, and evening).
GEn 1200 mg/Day	One 600 mg extended release (ER) GEn tablet and two 600 mg GEn placebo tablets taken orally twice daily (morning and evening); one 100 mg PGB placebo capsule taken orally three times daily (morning, midday, and evening).
GEn 2400 mg/Day	Two 600 mg ER GEn tablets and one 600 mg GEn placebo tablet taken orally twice daily (morning and evening); one 100 mg PGB placebo capsule taken orally three times daily (morning, midday, and evening).
GEn 3600 mg/Day	Three 600 mg ER GEn tablets taken orally twice daily (morning and evening); one 100 mg PGB placebo capsule taken orally three times daily (morning, midday, and evening).
PGB 300 mg/Day	Three 600 mg GEn placebo tablets taken orally twice daily (morning and evening); one 100 mg PGB capsule taken orally three times daily (morning, midday, and evening).
Total	Total of all reporting groups

Baseline Measures

Placebo

GEn 1200 mg/Day

GEn 2400 mg/Day

GEn 3600 mg/Day

PGB 300 mg/Day

Total

Overall Participants Analyzed
[Units: Participants]

120

62

56

116

66

420

Age ^[1]
[Units: Years]
Mean (Standard Deviation)

60.1 (10.63)

57.5 (10.32)

60.8 (8.97)

57.5 (9.87)

57.7 (10.59)

58.7 (10.20)

^[1]	Age in years of the Intent-to-Treat (ITT) Population, comprised of all randomized participants who took at least one dose of investigational product and provided at least one post-baseline efficacy measurement, was used for all baseline characteristics. This population does not include all participants randomized to study treatment.

Gender ^[1]
[Units: Participants]

Female

47

28

19

45

32

171

Male

73

34

37

71

34

249

^[1]	Gender of the ITT Population, comprised of all randomized participants who took at least one dose of investigational product and provided at least one post-baseline efficacy measurement, was used for all baseline characteristics. This population does not include all participants randomized to study treatment.

Race/Ethnicity, Customized ^[1]
[Units: Participants]

African American/African Heritage

20

15

7

20

12

74

American Indian or Alaskan Native

2

0

2

Asian - Central/South Asian Heritage

0

1

0

1

Asian - South East Asian Heritage

0

1

0

2

0

3

White - Arabic/North African Heritage

0

2

1

0

5

White - White/Caucasian/European Heritage

98

44

45

89

52

328

Mixed Race

0

1

0

2

Not Provided

0

1

2

5

^[1]	Race of the ITT Population, comprised of all randomized participants who took at least one dose of investigational product and provided at least one post-baseline efficacy measurement, was used for all baseline characteristics. This population does not include all participants randomized to study treatment.

Outcome Measures

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1. Primary:

Change From Baseline in the Mean 24-hour Average Pain Intensity (API) Score at End of Maintenance Treatment (EOMT) Using Last Observation Carried Forward (LOCF) Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

Show Outcome Measure 1

2. Secondary:

Change From Baseline in the Mean Day-time Average Pain Intensity (API) Score at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

Show Outcome Measure 2

3. Secondary:

Change From Baseline in the Mean Night-time Average Pain Intensity (API) Score at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

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4. Secondary:

Change From Baseline in the Mean Current (Morning) Pain Intensity Score at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

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5. Secondary:

Change From Baseline in the Mean Current (Evening) Pain Intensity Score at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

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6. Secondary:

Change From Baseline in the Mean Day-time Worst Pain Intensity Score at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

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7. Secondary:

Change From Baseline in the Mean Night-time Worst Pain Intensity Score at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

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8. Secondary:

Change From Baseline in the Mean Sleep Interference Score at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

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9. Secondary:

Change From Baseline in the Mean Daily Dose of Rescue Medication at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

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10. Secondary:

Change From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

Show Outcome Measure 10

11. Secondary:

Change From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

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12. Secondary:

Change From Baseline in Pain Score After Taking a 50-foot Walk at EOMT [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

Show Outcome Measure 12

13. Secondary:

Number of Participants Who Are Responders on the Patient Global Impression of Change (PGIC) Questionnaire at EOMT Using LOCF Data [ Time Frame: EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

Show Outcome Measure 13

14. Secondary:

Number of Participants Who Are Responders on the Clinician Global Impression of Change (CGIC) Questionnaire at EOMT Using LOCF Data [ Time Frame: EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

Show Outcome Measure 14

15. Secondary:

Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

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16. Secondary:

Time to Onset of Sustained Improvement in the 24-hour Average Pain Intensity Score [ Time Frame: Any time post-baseline until date of last dose of study medication (up to Week 13) ]

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17. Secondary:

Change From Baseline in Severity of Pain and the Impact of Pain as Assessed by the Brief Pain Inventory (BPI) at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT ]

Show Outcome Measure 17

18. Secondary:

Change From Baseline in Quality of Life as Assessed by the 36-Item Short Form Health Survey (SF-36) at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

Show Outcome Measure 18

19. Secondary:

Change From Baseline in Emotional Functioning as Assessed by the Profile of Mood States-Brief Form (POMS-B) at EOMT Using LOCF Data [ Time Frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit) ]

Show Outcome Measure 19

Serious Adverse Events

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Other Adverse Events

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Limitations and Caveats

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Limitations of the study, such as early termination leading to small numbers of participants analyzed and technical problems with measurement leading to unreliable or uninterpretable data
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More Information

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Certain Agreements:

Principal Investigators are NOT employed by the organization sponsoring the study.

There IS an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.

The agreement is:

	The only disclosure restriction on the PI is that the sponsor can review results communications prior to public release and can embargo communications regarding trial results for a period that is less than or equal to 60 days. The sponsor cannot require changes to the communication and cannot extend the embargo.
	The only disclosure restriction on the PI is that the sponsor can review results communications prior to public release and can embargo communications regarding trial results for a period that is more than 60 days but less than or equal to 180 days. The sponsor cannot require changes to the communication and cannot extend the embargo.
	Other disclosure agreement that restricts the right of the PI to discuss or publish trial results after the trial is completed. Restriction Description: 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.

Results Point of Contact:

Name/Title: XenoPort Call Center
Organization: XenoPort, Inc.
phone: 877-936-6778

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):

Rauck R, Makumi CW, Schwartz S, Graff O, Meno-Tetang G, Bell CF, Kavanagh ST, McClung CL. A randomized, controlled trial of gabapentin enacarbil in subjects with neuropathic pain associated with diabetic peripheral neuropathy. Pain Pract. 2013 Jul;13(6):485-96. doi: 10.1111/papr.12014. Epub 2012 Nov 27.

Responsible Party:	XenoPort, Inc.
ClinicalTrials.gov Identifier:	NCT00643760 History of Changes
Other Study ID Numbers:	110448
Study First Received:	February 19, 2008
Results First Received:	April 21, 2011
Last Updated:	July 15, 2013