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A Study In Patients With Neuropathic Pain From Post-Herpetic Neuralgia (PHN)

Study PXN110748: An Efficacy and Safety Study of XP13512 Compared With a Concurrent Placebo Control in Subjects With Neuropathic Pain Associated With Post-herpetic Neuralgia (PHN)

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT00619476
Enrollment
376
Registered
2008-02-21
Start date
2008-02-29
Completion date
2009-07-31
Last updated
2013-07-22

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Neuralgia, Postherpetic

Keywords

Neuropathic Pain, Post-herpetic neuralgia, PHN

Brief summary

The purpose of this study is to determine whether gabapentin enacarbil (XP13512/GSK1838262), hereafter referred to as GEn is effective in the treatment of neuropathic pain associated with post-herpetic neuralgia (PHN).

Detailed description

The primary purpose of study PXN110748 was to evaluate efficacy and safety of 3 fixed doses of GEn in the treatment of PHN.

Interventions

gabapentin enacarbil 1200mg/day

gabapentin enacarbil 2400mg/day

gabapentin enacarbil 3600mg/day

DRUGPlacebo

placebo

Sponsors

XenoPort, Inc.
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* 18 years or older * Female subjects are eligible if of non-childbearing potential or not lactating, has a negative pregnancy, and agrees to use one a specified highly effective method for avoiding pregnancy * Documented medical diagnosis of PHN of with pain present for at least three months from the healing of a herpes zoster rash * Baseline 24-hour average pain intensity score ≥ 4.0 based on an 11-point PI-NRS * Provides written informed consent in accordance with all applicable regulatory requirements

Exclusion criteria

* Other chronic pain conditions not associated with PHN. However, the subject will not be excluded if: * The pain is located at a different region of the body; and * The pain intensity is not greater than the pain intensity of the PHN; and * The subject can assess PHN pain independently of other pain * Is unable to discontinue prohibited medications or non-drug therapies or procedures throughout the duration of the study * Hepatic impairment defined as ALT or AST \> 2x upper limit of normal (ULN), or alkaline phosphatase or bilirubin \> 1.5x ULN * Chronic hepatitis B or C * Impaired renal function defined as creatinine clearance \<60 mL/min or requiring hemodialysis * Corrected QT (QTc) interval ≥ 450 msec or QTc interval ≥480 msec for patients with Bundle Branch Block * Uncontrolled hypertension at screen (sitting systolic \>160 mmHg and/or sitting diastolic \>90 mmHg) * Current diagnosis of active epilepsy or any active seizure disorder requiring chronic therapy with antiepileptic drugs * Medical condition or disorder that would interfere with the action, absorption, distribution, metabolism, or excretion of GEn, or, in the investigator's judgment * Is considered to be clinically significant and may pose a safety concern, or, * Could interfere with the accurate assessment of safety or efficacy, or, * Could potentially affect a subject's safety or study outcome * Meets criteria defined by the DSM-IV-TR for a major depressive episode or for active significant psychiatric disorders within last year * Depression in remission, with or without antidepressant treatment, may participate, unless stable antidepressant regimen is a prohibited medication * Antidepressant medication may not be changed or discontinued to meet entry criteria and must be stable for at least three months prior to enrollment * History of clinically significant drug or alcohol abuse (DSM-IV-TR) or is unable to refrain from substance abuse throughout the study. Benzodiazepines or atypical benzodiazepines as hypnotic sleep agents permitted. * Currently participating in another clinical study in which the subject is, or will be exposed to an investigational or non-investigational drug or device * Has participated in a clinical study and was exposed to investigational or non-investigational drug or device: * Within preceding month for studies unrelated to PHN, or * Within preceding six months for studies related to PHN * Treated previously with GEn * History of allergic or medically significant adverse reaction to investigational products (including gabapentin) or their excipients, acetaminophen or related compounds

Design outcomes

Primary

MeasureTime frameDescription
Change From Baseline in the Mean 24-hour Average Pain Intensity (API) Score at the End of Maintenance Treatment (EOMT) Using Last Observation Carried Forward (LOCF) DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)Baseline and EOMT 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 earliest date of Week 13 visit/Withdrawal visit/last dose of study drug (EOMT). Participants used a hand-held diary to rate their average pain intensity 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 EOMT score minus Baseline score.

Secondary

MeasureTime frameDescription
Change From Baseline in the Mean Current Morning Pain Intensity Score at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)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 EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.
Change From Baseline in the Mean Night-time Worst Pain Intensity Score at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)Night-time worst pain is defined as the participant's assessment of their worst pain between going to bed at night and rising in the morning. Participants recorded night-time worst pain in the morning upon awakening using an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). Baseline and EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.
Change From Baseline in the Mean Sleep Interference Score at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)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 EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.
Change From Baseline in the Mean Day-time Average Pain Intensity(API) Score at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)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 EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.
Change From Baseline in the Mean Current Evening Pain Intensity Score at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)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 EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.
Change From Baseline in the Mean Day-time Worst Pain Intensity Score at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)Day-time worst pain is defined as the participant's assessment of their worst pain between rising in the morning and going to bed at night. Participants recorded day-time worst pain in the evening before bedtime using an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). Baseline and EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.
Change From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)The NPS assesses pain qualities and consists of 11-items, 10 assessed on an 11-point NRS (0=no impact to 10=greatest impact); and 1 open-ended question not used in score calculation. 4 summary scores are calculated: NPS 10 (items 1-7, 9-11), NPS 8 (8 pain descriptor items), NPS Non-Allodynic (NA) (8 NA items), and NPS 4 (4 pain quality items); and range from 0 to 100 (0=no impact and 100=greatest impact). The analysis 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.
Change From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)The SF-MPQ, a general pain instrument, assesses the characteristics and intensity of pain and consists of 15-items assessed on a 4-point scale (0=none, 1=mild, 2=moderate, and 3=severe). 3 summary scores are calculated: sensory score (sum of items 1-11, range 0-33), affective score (sum of items 12-15, range 0-12), total score (sum of items 1-15, range 0-45), where lower scores = lower pain/impact. Analysis 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.
Change From Baseline in the Mean Night-time Average Pain Intensity (API) Score at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)Night-time is defined as the time between going to bed at night and rising in the morning. Participants recorded night-time API on a daily basis in the morning upon awakening using an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). Baseline and EOMT are as defined for the primary endpoint. Change from baseline wss calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.
Number of Participants Who Are Responders on the Patient Global Impression of Change (PGIC) Questionnaire at EOMT Using LOCF DataEOMT (representing the earliest date of Week 13 visit/withdrawal visit)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. EOMT response is defined as the score recorded at the Week13/Withdrawal visit.
Number of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)Baseline and EOMT scores are the calculated means of the 24-hour average pain scores for each participant during the last 7 days prior to randomization and EOMT, respectively. Percent reduction from baseline was calculated as the \[(EOMT score minus the baseline score)divided by the baseline score\], 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.
Time to Onset of Sustained Improvement in the 24-hour Average Pain Intensity ScoreAnytime post-baseline until date of last dose of study medication (up to Week 13)Sustained improvement in the 24-hour average pain intensity score is defined as at least 2 consecutive days on which the 24-hour average pain intensity score is \>=2 points less than the mean 24-hour average pain intensity score at baseline. Time to onset is measured from baseline and was calculated as the first day of event minus the last day of baseline and is expressed in days. Baseline score is the calculated mean of the 24-hour average pain score for each participant during the last 7 days prior to randomization.
Change From Baseline in the Mean Daily Dose in Milligrams of Rescue Medication at EOMT Using LOCF DataBaseline and EOMT (Week 13 or early withdrawal)Mean daily use of rescue medication (milligrams of acetaminophen) was calculated by determining the average number of tablets taken per day of rescue medication (Commerical Tylenol) during treatment and multiplying that by 500 mg. Baseline and EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.
Change From Baseline in Severity of Pain and the Impact of Pain as Assessed by the Brief Pain Inventory (BPI) at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)The BPI, a general pain instrument, assesses the severity and interference of pain; and consists of 6 items assessed on an 11-point NRS (0=no impact and 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 each summary score ranges from 0 to 10 (0=no impact and 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.
Change From Baseline in Quality of Life as Assessed by the SF-36 at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)The SF-36 is a general health-related quality of life instrument consisting of 36 items with various response options (Yes/No, 5- to 6-point Likert scale). Summary scores are calculated for 8 domains and 2 components (physical and mental); where scores range from 0 to 100 (higher scores = better quality of life). 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.
Change From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)The POMS-B, an emotional functioning instrument, assesses mood, tension, and other psychological symptoms and consists of 30-items assessed on a 5-point scale (0=not at all to 4=extremely). 6 summary scores are calculated: Tension/Anxiety, Depression/Rejection, Anger/Hostility, Vigor/Activity, Fatigue/Inertia, and Confusion/Bewilderment; and range from 0-20 (higher scores = more negative mood state). 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.
Number of Participants Who Are Responders on the Clinician Global Impression of Change (CGIC) Questionnaire at EOMT Using LOCF DataEOMT (representing the earliest date of Week 13 visit/withdrawal visit)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. EOMT response is defined as the score recorded at the Week13/Withdrawal visit.
Change From Baseline in Dynamic Allodynia at EOMT Using LOCF DataBaseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)Dynamic allodynia (pain in response to a standardized light touch stimulus, a foam brush applied with light pressure to the site of maximum pain) was assessed by an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). Baseline and EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.

Countries

Canada, United States

Participant flow

Participants by arm

ArmCount
Placebo
Three 600 milligram (mg) gabapentin enacarbil (XP13512/GSK1838262), hereafter referred to as GEn, placebo tablets taken orally twice daily (morning and evening)
95
GEn 1200 mg/Day
One 600 mg GEn tablet and two GEn placebo tablets taken orally twice daily (morning and evening)
107
GEn 2400 mg/Day
Two 600 mg GEn tablets and one GEN placebo tablet taken orally twice daily (morning and evening)
82
GEn 3600 mg/Day
Three 600 mg GEn tablets taken orally twice daily (morning and evening)
87
Total371

Withdrawals & dropouts

PeriodReasonFG000FG001FG002FG003
Overall StudyAdverse Event1261216
Overall StudyInvestigator Discretion2220
Overall StudyLack of Efficacy6114
Overall StudyLost to Follow-up1201
Overall StudyProtocol Violation5449
Overall StudyWithdrawal by Subject5754

Baseline characteristics

CharacteristicPlaceboGEn 1200 mg/DayGEn 2400 mg/DayGEn 3600 mg/DayTotal
Age Continuous61.7 Years
STANDARD_DEVIATION 12.77
61.7 Years
STANDARD_DEVIATION 12.58
64.1 Years
STANDARD_DEVIATION 8.94
61.3 Years
STANDARD_DEVIATION 15.41
62.1 Years
STANDARD_DEVIATION 12.67
Race/Ethnicity, Customized
African American/African Heritage
14 participants11 participants8 participants11 participants44 participants
Race/Ethnicity, Customized
American Indian or Alaskan Native
0 participants0 participants2 participants1 participants3 participants
Race/Ethnicity, Customized
Asian - Central/South Asian Heritage
1 participants0 participants1 participants0 participants2 participants
Race/Ethnicity, Customized
Asian - Japanese/ East Asian Heritage
0 participants1 participants1 participants1 participants3 participants
Race/Ethnicity, Customized
Native Hawaiian or other Pacific Islander
0 participants0 participants0 participants1 participants1 participants
Race/Ethnicity, Customized
Not Provided
1 participants1 participants1 participants0 participants3 participants
Race/Ethnicity, Customized
White
79 participants94 participants69 participants73 participants315 participants
Sex: Female, Male
Female
45 Participants54 Participants35 Participants48 Participants182 Participants
Sex: Female, Male
Male
50 Participants53 Participants47 Participants39 Participants189 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
EG002
affected / at risk
EG003
affected / at risk
deaths
Total, all-cause mortality
— / —— / —— / —— / —
other
Total, other adverse events
63 / 12075 / 10764 / 8271 / 87
serious
Total, serious adverse events
2 / 950 / 1076 / 822 / 87

Outcome results

Primary

Change From Baseline in the Mean 24-hour Average Pain Intensity (API) Score at the End of Maintenance Treatment (EOMT) Using Last Observation Carried Forward (LOCF) Data

Baseline and EOMT 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 earliest date of Week 13 visit/Withdrawal visit/last dose of study drug (EOMT). Participants used a hand-held diary to rate their average pain intensity 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 EOMT score minus Baseline score.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population: all randomized participants who took at least one dose of investigational product and provided at least one post-baseline efficacy measurement.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in the Mean 24-hour Average Pain Intensity (API) Score at the End of Maintenance Treatment (EOMT) Using Last Observation Carried Forward (LOCF) Data-1.66 points on a scaleStandard Error 0.216
GEn 1200 mg/DayChange From Baseline in the Mean 24-hour Average Pain Intensity (API) Score at the End of Maintenance Treatment (EOMT) Using Last Observation Carried Forward (LOCF) Data-2.47 points on a scaleStandard Error 0.204
GEn 2400 mg/DayChange From Baseline in the Mean 24-hour Average Pain Intensity (API) Score at the End of Maintenance Treatment (EOMT) Using Last Observation Carried Forward (LOCF) Data-2.36 points on a scaleStandard Error 0.237
GEn 3600 mg/DayChange From Baseline in the Mean 24-hour Average Pain Intensity (API) Score at the End of Maintenance Treatment (EOMT) Using Last Observation Carried Forward (LOCF) Data-2.72 points on a scaleStandard Error 0.227
p-value: 0.01395% CI: [-1.4, -0.23]ANCOVA
p-value: 0.02995% CI: [-1.33, -0.07]ANCOVA
p-value: 0.00295% CI: [-1.68, -0.45]ANCOVA
Secondary

Change From Baseline in Dynamic Allodynia at EOMT Using LOCF Data

Dynamic allodynia (pain in response to a standardized light touch stimulus, a foam brush applied with light pressure to the site of maximum pain) was assessed by an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). Baseline and EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. The NRS analysis included a subset of the ITT Population who completed that NRS at both the Baseline and the Week13/Withdrawal Visit.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in Dynamic Allodynia at EOMT Using LOCF Data-2.29 points on a scaleStandard Error 0.15
GEn 1200 mg/DayChange From Baseline in Dynamic Allodynia at EOMT Using LOCF Data-1.97 points on a scaleStandard Error 0.137
GEn 2400 mg/DayChange From Baseline in Dynamic Allodynia at EOMT Using LOCF Data-2.16 points on a scaleStandard Error 0.161
GEn 3600 mg/DayChange From Baseline in Dynamic Allodynia at EOMT Using LOCF Data-2.25 points on a scaleStandard Error 0.161
Secondary

Change From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF Data

The POMS-B, an emotional functioning instrument, assesses mood, tension, and other psychological symptoms and consists of 30-items assessed on a 5-point scale (0=not at all to 4=extremely). 6 summary scores are calculated: Tension/Anxiety, Depression/Rejection, Anger/Hostility, Vigor/Activity, Fatigue/Inertia, and Confusion/Bewilderment; and range from 0-20 (higher scores = more negative mood state). 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.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. Not all participants completed a POMS-B at both Baseline and Week 13/Withdrawal; as such, the number analyzed is different from the full ITT Population counts.

ArmMeasureGroupValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataTension/Anxiety Domain Score-1.6 points on a scaleStandard Error 0.29
PlaceboChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataAnger/Hostility Domain Score-1.6 points on a scaleStandard Error 0.29
PlaceboChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataVigor/Activity Domain Score0.4 points on a scaleStandard Error 0.38
PlaceboChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataFatigue/Inertia Domain Score-1.4 points on a scaleStandard Error 0.4
PlaceboChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataDepression/Rejection Domain Score-1.4 points on a scaleStandard Error 0.28
PlaceboChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataConfusion/Bewilderment Domain Score-0.7 points on a scaleStandard Error 0.25
GEn 1200 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataAnger/Hostility Domain Score-2.0 points on a scaleStandard Error 0.27
GEn 1200 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataDepression/Rejection Domain Score-1.5 points on a scaleStandard Error 0.26
GEn 1200 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataFatigue/Inertia Domain Score-1.9 points on a scaleStandard Error 0.37
GEn 1200 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataTension/Anxiety Domain Score-1.8 points on a scaleStandard Error 0.26
GEn 1200 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataVigor/Activity Domain Score0.8 points on a scaleStandard Error 0.35
GEn 1200 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataConfusion/Bewilderment Domain Score-0.5 points on a scaleStandard Error 0.22
GEn 2400 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataFatigue/Inertia Domain Score-2.4 points on a scaleStandard Error 0.43
GEn 2400 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataAnger/Hostility Domain Score-2.4 points on a scaleStandard Error 0.31
GEn 2400 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataVigor/Activity Domain Score0.5 points on a scaleStandard Error 0.41
GEn 2400 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataConfusion/Bewilderment Domain Score-1.0 points on a scaleStandard Error 0.26
GEn 2400 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataTension/Anxiety Domain Score-2.0 points on a scaleStandard Error 0.3
GEn 2400 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataDepression/Rejection Domain Score-1.9 points on a scaleStandard Error 0.3
GEn 3600 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataConfusion/Bewilderment Domain Score-0.5 points on a scaleStandard Error 0.26
GEn 3600 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataDepression/Rejection Domain Score-1.7 points on a scaleStandard Error 0.3
GEn 3600 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataTension/Anxiety Domain Score-2.0 points on a scaleStandard Error 0.3
GEn 3600 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataVigor/Activity Domain Score1.4 points on a scaleStandard Error 0.41
GEn 3600 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataFatigue/Inertia Domain Score-2.5 points on a scaleStandard Error 0.43
GEn 3600 mg/DayChange From Baseline in Emotional Functioning as Assessed by the POMS-B at EOMT Using LOCF DataAnger/Hostility Domain Score-1.7 points on a scaleStandard Error 0.31
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

The SF-MPQ, a general pain instrument, assesses the characteristics and intensity of pain and consists of 15-items assessed on a 4-point scale (0=none, 1=mild, 2=moderate, and 3=severe). 3 summary scores are calculated: sensory score (sum of items 1-11, range 0-33), affective score (sum of items 12-15, range 0-12), total score (sum of items 1-15, range 0-45), where lower scores = lower pain/impact. Analysis 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.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. The SF-MPQ analysis included a subset of the ITT Population who completed a SF-MPQ assessment at both Baseline and the Week 13/Withdrawal Visit.

ArmMeasureGroupValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataSF-MPQ Sensory Score-4.51 points on a scaleStandard Error 0.737
PlaceboChange From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataSF-MPQ Affective Score-1.58 points on a scaleStandard Error 0.27
PlaceboChange From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataSF-MPQ Total Score-6.08 points on a scaleStandard Error 0.949
GEn 1200 mg/DayChange From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataSF-MPQ Total Score-8.35 points on a scaleStandard Error 0.869
GEn 1200 mg/DayChange From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataSF-MPQ Affective Score-2.27 points on a scaleStandard Error 0.247
GEn 1200 mg/DayChange From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataSF-MPQ Sensory Score-6.07 points on a scaleStandard Error 0.675
GEn 2400 mg/DayChange From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataSF-MPQ Sensory Score-5.43 points on a scaleStandard Error 0.795
GEn 2400 mg/DayChange From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataSF-MPQ Total Score-7.45 points on a scaleStandard Error 1.024
GEn 2400 mg/DayChange From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataSF-MPQ Affective Score-2.08 points on a scaleStandard Error 0.291
GEn 3600 mg/DayChange From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataSF-MPQ Total Score-8.15 points on a scaleStandard Error 1.006
GEn 3600 mg/DayChange From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataSF-MPQ Affective Score-1.99 points on a scaleStandard Error 0.286
GEn 3600 mg/DayChange From Baseline in Pain Characteristics and Intensity as Assessed by the Short Form-McGill Pain Questionnaire (SF-MPQ) at EOMT Using LOCF DataSF-MPQ Sensory Score-6.13 points on a scaleStandard Error 0.782
Secondary

Change From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF Data

The NPS assesses pain qualities and consists of 11-items, 10 assessed on an 11-point NRS (0=no impact to 10=greatest impact); and 1 open-ended question not used in score calculation. 4 summary scores are calculated: NPS 10 (items 1-7, 9-11), NPS 8 (8 pain descriptor items), NPS Non-Allodynic (NA) (8 NA items), and NPS 4 (4 pain quality items); and range from 0 to 100 (0=no impact and 100=greatest impact). The analysis 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.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. The NPS summary included a subset of the ITT Population that completed an NPS assessment at both Baseline and Week 13/Withdrawal.

ArmMeasureGroupValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS 10 Score-17.17 points on a scaleStandard Error 2.094
PlaceboChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS 8 Score-17.05 points on a scaleStandard Error 2.059
PlaceboChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS Non-Allodynic Score-16.87 points on a scaleStandard Error 2.107
PlaceboChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS 4 Score-18.25 points on a scaleStandard Error 2.34
GEn 1200 mg/DayChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS 8 Score-22.23 points on a scaleStandard Error 1.875
GEn 1200 mg/DayChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS Non-Allodynic Score-22.58 points on a scaleStandard Error 1.92
GEn 1200 mg/DayChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS 4 Score-24.37 points on a scaleStandard Error 2.133
GEn 1200 mg/DayChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS 10 Score-22.78 points on a scaleStandard Error 1.907
GEn 2400 mg/DayChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS Non-Allodynic Score-24.18 points on a scaleStandard Error 2.269
GEn 2400 mg/DayChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS 8 Score-23.77 points on a scaleStandard Error 2.217
GEn 2400 mg/DayChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS 4 Score-26.08 points on a scaleStandard Error 2.519
GEn 2400 mg/DayChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS 10 Score-24.02 points on a scaleStandard Error 2.256
GEn 3600 mg/DayChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS 4 Score-26.55 points on a scaleStandard Error 2.464
GEn 3600 mg/DayChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS 8 Score-24.49 points on a scaleStandard Error 2.165
GEn 3600 mg/DayChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS 10 Score-25.2 points on a scaleStandard Error 2.202
GEn 3600 mg/DayChange From Baseline in Pain Quality as Assessed by the Neuropathic Pain Scale (NPS) Summary Scores at EOMT Using LOCF DataNPS Non-Allodynic Score-24.54 points on a scaleStandard Error 2.216
Secondary

Change From Baseline in Quality of Life as Assessed by the SF-36 at EOMT Using LOCF Data

The SF-36 is a general health-related quality of life instrument consisting of 36 items with various response options (Yes/No, 5- to 6-point Likert scale). Summary scores are calculated for 8 domains and 2 components (physical and mental); where scores range from 0 to 100 (higher scores = better quality of life). 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.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. Not all participants completed an SF-36 at both Baseline and Week 13/Withdrawal; as such, the number analyzed is different from the full ITT Population counts.

ArmMeasureGroupValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in Quality of Life as Assessed by the SF-36 at EOMT Using LOCF DataSF-36 Mental Component Summary Score3.2 points on a scaleStandard Error 0.92
PlaceboChange From Baseline in Quality of Life as Assessed by the SF-36 at EOMT Using LOCF DataSF-36 Physical Component Summary Score3.3 points on a scaleStandard Error 0.74
GEn 1200 mg/DayChange From Baseline in Quality of Life as Assessed by the SF-36 at EOMT Using LOCF DataSF-36 Mental Component Summary Score5.1 points on a scaleStandard Error 0.85
GEn 1200 mg/DayChange From Baseline in Quality of Life as Assessed by the SF-36 at EOMT Using LOCF DataSF-36 Physical Component Summary Score4.3 points on a scaleStandard Error 0.67
GEn 2400 mg/DayChange From Baseline in Quality of Life as Assessed by the SF-36 at EOMT Using LOCF DataSF-36 Mental Component Summary Score4.5 points on a scaleStandard Error 0.99
GEn 2400 mg/DayChange From Baseline in Quality of Life as Assessed by the SF-36 at EOMT Using LOCF DataSF-36 Physical Component Summary Score4.4 points on a scaleStandard Error 0.79
GEn 3600 mg/DayChange From Baseline in Quality of Life as Assessed by the SF-36 at EOMT Using LOCF DataSF-36 Physical Component Summary Score4.9 points on a scaleStandard Error 0.78
GEn 3600 mg/DayChange From Baseline in Quality of Life as Assessed by the SF-36 at EOMT Using LOCF DataSF-36 Mental Component Summary Score5.8 points on a scaleStandard Error 0.99
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

The BPI, a general pain instrument, assesses the severity and interference of pain; and consists of 6 items assessed on an 11-point NRS (0=no impact and 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 each summary score ranges from 0 to 10 (0=no impact and 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.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. Not all participants completed a BPI assessment at both Baseline and Week 13/Withdrawal; as such, the number analyzed is different from the full ITT Population counts.

ArmMeasureGroupValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in Severity of Pain and the Impact of Pain as Assessed by the Brief Pain Inventory (BPI) at EOMT Using LOCF DataBrief Pain Inventory Interference of Pain-2.0 points on a scaleStandard Error 0.2
PlaceboChange From Baseline in Severity of Pain and the Impact of Pain as Assessed by the Brief Pain Inventory (BPI) at EOMT Using LOCF DataBrief Pain Inventory Severity of Pain-1.8 points on a scaleStandard Error 0.22
GEn 1200 mg/DayChange From Baseline in Severity of Pain and the Impact of Pain as Assessed by the Brief Pain Inventory (BPI) at EOMT Using LOCF DataBrief Pain Inventory Severity of Pain-2.4 points on a scaleStandard Error 0.2
GEn 1200 mg/DayChange From Baseline in Severity of Pain and the Impact of Pain as Assessed by the Brief Pain Inventory (BPI) at EOMT Using LOCF DataBrief Pain Inventory Interference of Pain-2.2 points on a scaleStandard Error 0.19
GEn 2400 mg/DayChange From Baseline in Severity of Pain and the Impact of Pain as Assessed by the Brief Pain Inventory (BPI) at EOMT Using LOCF DataBrief Pain Inventory Interference of Pain-2.2 points on a scaleStandard Error 0.22
GEn 2400 mg/DayChange From Baseline in Severity of Pain and the Impact of Pain as Assessed by the Brief Pain Inventory (BPI) at EOMT Using LOCF DataBrief Pain Inventory Severity of Pain-2.4 points on a scaleStandard Error 0.24
GEn 3600 mg/DayChange From Baseline in Severity of Pain and the Impact of Pain as Assessed by the Brief Pain Inventory (BPI) at EOMT Using LOCF DataBrief Pain Inventory Severity of Pain-2.5 points on a scaleStandard Error 0.24
GEn 3600 mg/DayChange From Baseline in Severity of Pain and the Impact of Pain as Assessed by the Brief Pain Inventory (BPI) at EOMT Using LOCF DataBrief Pain Inventory Interference of Pain-2.3 points on a scaleStandard Error 0.22
Secondary

Change From Baseline in the Mean Current Evening Pain Intensity Score at EOMT Using LOCF Data

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 EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. There was one participant in the GEn 1200 mg group and two in the 2400 mg group who did not complete enough post-baseline evening diaries to calculate a score for the EMOT timepoint.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in the Mean Current Evening Pain Intensity Score at EOMT Using LOCF Data-1.45 points on a scaleStandard Error 0.225
GEn 1200 mg/DayChange From Baseline in the Mean Current Evening Pain Intensity Score at EOMT Using LOCF Data-2.45 points on a scaleStandard Error 0.213
GEn 2400 mg/DayChange From Baseline in the Mean Current Evening Pain Intensity Score at EOMT Using LOCF Data-2.24 points on a scaleStandard Error 0.247
GEn 3600 mg/DayChange From Baseline in the Mean Current Evening Pain Intensity Score at EOMT Using LOCF Data-2.69 points on a scaleStandard Error 0.236
Secondary

Change From Baseline in the Mean Current Morning Pain Intensity Score at EOMT Using LOCF Data

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 EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. There was one participant in the GEn 2400 mg group and one in the 3600 mg group who did not complete enough post-baseline morning diaries to calculate an API for the EMOT timepoint.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in the Mean Current Morning Pain Intensity Score at EOMT Using LOCF Data-1.34 points on a scaleStandard Error 0.223
GEn 1200 mg/DayChange From Baseline in the Mean Current Morning Pain Intensity Score at EOMT Using LOCF Data-2.29 points on a scaleStandard Error 0.209
GEn 2400 mg/DayChange From Baseline in the Mean Current Morning Pain Intensity Score at EOMT Using LOCF Data-2.13 points on a scaleStandard Error 0.242
GEn 3600 mg/DayChange From Baseline in the Mean Current Morning Pain Intensity Score at EOMT Using LOCF Data-2.41 points on a scaleStandard Error 0.234
Secondary

Change From Baseline in the Mean Daily Dose in Milligrams of Rescue Medication at EOMT Using LOCF Data

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

Time frame: Baseline and EOMT (Week 13 or early withdrawal)

Population: ITT Population. There was one participant in the GEn 1200 mg and two in the GEn 2400 mg group who did not have enough data available to calculate the rescue mediation consumed while on treatment.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in the Mean Daily Dose in Milligrams of Rescue Medication at EOMT Using LOCF Data-41.00 milligramsStandard Error 89.488
GEn 1200 mg/DayChange From Baseline in the Mean Daily Dose in Milligrams of Rescue Medication at EOMT Using LOCF Data-289.94 milligramsStandard Error 84.35
GEn 2400 mg/DayChange From Baseline in the Mean Daily Dose in Milligrams of Rescue Medication at EOMT Using LOCF Data-260.03 milligramsStandard Error 97.853
GEn 3600 mg/DayChange From Baseline in the Mean Daily Dose in Milligrams of Rescue Medication at EOMT Using LOCF Data-266.21 milligramsStandard Error 93.503
Secondary

Change From Baseline in the Mean Day-time Average Pain Intensity(API) Score at EOMT Using LOCF Data

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 EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. There was one participant in the GEn 1200 mg group and two in the 2400 mg group who did not complete enough post-baseline evening diaries to calculate an API for the EOMT timepoint.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in the Mean Day-time Average Pain Intensity(API) Score at EOMT Using LOCF Data-1.59 points on a scaleStandard Error 0.218
GEn 1200 mg/DayChange From Baseline in the Mean Day-time Average Pain Intensity(API) Score at EOMT Using LOCF Data-2.47 points on a scaleStandard Error 0.206
GEn 2400 mg/DayChange From Baseline in the Mean Day-time Average Pain Intensity(API) Score at EOMT Using LOCF Data-2.23 points on a scaleStandard Error 0.239
GEn 3600 mg/DayChange From Baseline in the Mean Day-time Average Pain Intensity(API) Score at EOMT Using LOCF Data-2.67 points on a scaleStandard Error 0.229
Secondary

Change From Baseline in the Mean Day-time Worst Pain Intensity Score at EOMT Using LOCF Data

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

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. There was one participant in the GEn 1220 mg group and two in the 2400 mg group who did not complete enough post-baseline evening diaries to calculate a score for the EOMT timepoint.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in the Mean Day-time Worst Pain Intensity Score at EOMT Using LOCF Data-1.74 points on a scaleStandard Error 0.242
GEn 1200 mg/DayChange From Baseline in the Mean Day-time Worst Pain Intensity Score at EOMT Using LOCF Data-2.61 points on a scaleStandard Error 0.229
GEn 2400 mg/DayChange From Baseline in the Mean Day-time Worst Pain Intensity Score at EOMT Using LOCF Data-2.41 points on a scaleStandard Error 0.265
GEn 3600 mg/DayChange From Baseline in the Mean Day-time Worst Pain Intensity Score at EOMT Using LOCF Data-2.82 points on a scaleStandard Error 0.253
Secondary

Change From Baseline in the Mean Night-time Average Pain Intensity (API) Score at EOMT Using LOCF Data

Night-time is defined as the time between going to bed at night and rising in the morning. Participants recorded night-time API on a daily basis in the morning upon awakening using an 11-point PI-NRS (0=no pain, 10=pain as bad as you can imagine). Baseline and EOMT are as defined for the primary endpoint. Change from baseline wss calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. There was one participant in the GEn 2400 mg group and one in the 3600 mg group who did not complete enough post-baseline morning diaries to calculate an API for the EOMT timepoint.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in the Mean Night-time Average Pain Intensity (API) Score at EOMT Using LOCF Data-1.65 points on a scaleStandard Error 0.219
GEn 1200 mg/DayChange From Baseline in the Mean Night-time Average Pain Intensity (API) Score at EOMT Using LOCF Data-2.35 points on a scaleStandard Error 0.206
GEn 2400 mg/DayChange From Baseline in the Mean Night-time Average Pain Intensity (API) Score at EOMT Using LOCF Data-2.44 points on a scaleStandard Error 0.238
GEn 3600 mg/DayChange From Baseline in the Mean Night-time Average Pain Intensity (API) Score at EOMT Using LOCF Data-2.50 points on a scaleStandard Error 0.231
Secondary

Change From Baseline in the Mean Night-time Worst Pain Intensity Score at EOMT Using LOCF Data

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

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. There was one participant in the GEn 2400 mg group and one in the 3600 mg group who did not complete enough post-baseline morning diaries to calculate an API for the EMOT timepoint.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in the Mean Night-time Worst Pain Intensity Score at EOMT Using LOCF Data-1.76 points on a scaleStandard Error 0.239
GEn 1200 mg/DayChange From Baseline in the Mean Night-time Worst Pain Intensity Score at EOMT Using LOCF Data-2.49 points on a scaleStandard Error 0.225
GEn 2400 mg/DayChange From Baseline in the Mean Night-time Worst Pain Intensity Score at EOMT Using LOCF Data-2.65 points on a scaleStandard Error 0.26
GEn 3600 mg/DayChange From Baseline in the Mean Night-time Worst Pain Intensity Score at EOMT Using LOCF Data-2.71 points on a scaleStandard Error 0.252
Secondary

Change From Baseline in the Mean Sleep Interference Score at EOMT Using LOCF Data

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 EOMT are as defined for the primary endpoint. Change from baseline was calculated as the EOMT score minus the baseline score. An ANCOVA model with baseline value, BMI, grouped center as covariates was used.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. There was one participant in the GEn 2400 mg group and one in the 3600 mg group who did not complete enough post-baseline morning diaries to calculate a score for the EMOT timepoint.

ArmMeasureValue (LEAST_SQUARES_MEAN)Dispersion
PlaceboChange From Baseline in the Mean Sleep Interference Score at EOMT Using LOCF Data-2.04 points on a scaleStandard Error 0.225
GEn 1200 mg/DayChange From Baseline in the Mean Sleep Interference Score at EOMT Using LOCF Data-2.72 points on a scaleStandard Error 0.212
GEn 2400 mg/DayChange From Baseline in the Mean Sleep Interference Score at EOMT Using LOCF Data-2.58 points on a scaleStandard Error 0.245
GEn 3600 mg/DayChange From Baseline in the Mean Sleep Interference Score at EOMT Using LOCF Data-2.78 points on a scaleStandard Error 0.237
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

Baseline and EOMT scores are the calculated means of the 24-hour average pain scores for each participant during the last 7 days prior to randomization and EOMT, respectively. Percent reduction from baseline was calculated as the \[(EOMT score minus the baseline score)divided by the baseline score\], 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.

Time frame: Baseline and EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. There was one participant in the GEn 1200 mg and one in the GEn 2400 mg group who did not have enough data available to calculate the percent reduction.

ArmMeasureGroupValue (NUMBER)
PlaceboNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 10% reduction from baseline62 participants
PlaceboNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>=0 reducation from baseline79 participants
PlaceboNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 60% reduction from baseline15 participants
PlaceboNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data100% reduction from baseline1 participants
PlaceboNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 80% reduction from baseline8 participants
PlaceboNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 90% reduction from baseline3 participants
PlaceboNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 50% reduction from baseline22 participants
PlaceboNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 40% reduction from baseline32 participants
PlaceboNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 70% reduction from baseline9 participants
PlaceboNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 30% reduction from baseline40 participants
PlaceboNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 20% reduction from baseline50 participants
GEn 1200 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 80% reduction from baseline17 participants
GEn 1200 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 60% reduction from baseline34 participants
GEn 1200 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 70% reduction from baseline25 participants
GEn 1200 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 90% reduction from baseline9 participants
GEn 1200 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data100% reduction from baseline6 participants
GEn 1200 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>=0 reducation from baseline94 participants
GEn 1200 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 10% reduction from baseline83 participants
GEn 1200 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 20% reduction from baseline71 participants
GEn 1200 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 30% reduction from baseline57 participants
GEn 1200 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 40% reduction from baseline50 participants
GEn 1200 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 50% reduction from baseline44 participants
GEn 2400 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>=0 reducation from baseline71 participants
GEn 2400 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 80% reduction from baseline12 participants
GEn 2400 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 10% reduction from baseline61 participants
GEn 2400 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 60% reduction from baseline14 participants
GEn 2400 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 20% reduction from baseline55 participants
GEn 2400 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 70% reduction from baseline18 participants
GEn 2400 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 30% reduction from baseline48 participants
GEn 2400 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 90% reduction from baseline9 participants
GEn 2400 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 50% reduction from baseline28 participants
GEn 2400 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data100% reduction from baseline3 participants
GEn 2400 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 40% reduction from baseline39 participants
GEn 3600 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 70% reduction from baseline24 participants
GEn 3600 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>=0 reducation from baseline84 participants
GEn 3600 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data100% reduction from baseline7 participants
GEn 3600 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 40% reduction from baseline46 participants
GEn 3600 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 30% reduction from baseline52 participants
GEn 3600 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 10% reduction from baseline70 participants
GEn 3600 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 50% reduction from baseline37 participants
GEn 3600 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 60% reduction from baseline31 participants
GEn 3600 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 90% reduction from baseline12 participants
GEn 3600 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 20% reduction from baseline65 participants
GEn 3600 mg/DayNumber of Participants Achieving Various Levels of Percent Reduction From Baseline in the Mean 24-hour Average Pain Intensity Score at EOMT Using LOCF Data>= 80% reduction from baseline19 participants
Secondary

Number of Participants Who Are Responders on the Clinician Global Impression of Change (CGIC) Questionnaire at EOMT Using LOCF Data

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. EOMT response is defined as the score recorded at the Week13/Withdrawal visit.

Time frame: EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. The CGIC analysis included a subset of the ITT Population who completed the PGIC questionnaire at the end of treatment.

ArmMeasureValue (NUMBER)
PlaceboNumber of Participants Who Are Responders on the Clinician Global Impression of Change (CGIC) Questionnaire at EOMT Using LOCF Data21 participants
GEn 1200 mg/DayNumber of Participants Who Are Responders on the Clinician Global Impression of Change (CGIC) Questionnaire at EOMT Using LOCF Data38 participants
GEn 2400 mg/DayNumber of Participants Who Are Responders on the Clinician Global Impression of Change (CGIC) Questionnaire at EOMT Using LOCF Data34 participants
GEn 3600 mg/DayNumber of Participants Who Are Responders on the Clinician Global Impression of Change (CGIC) Questionnaire at EOMT Using LOCF Data33 participants
Secondary

Number of Participants Who Are Responders on the Patient Global Impression of Change (PGIC) Questionnaire at EOMT Using LOCF Data

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. EOMT response is defined as the score recorded at the Week13/Withdrawal visit.

Time frame: EOMT (representing the earliest date of Week 13 visit/withdrawal visit)

Population: ITT Population. The PGIC analysis included a subset of the ITT Population who completed the PGIC questionnaire at the end of treatment.

ArmMeasureValue (NUMBER)
PlaceboNumber of Participants Who Are Responders on the Patient Global Impression of Change (PGIC) Questionnaire at EOMT Using LOCF Data24 participants
GEn 1200 mg/DayNumber of Participants Who Are Responders on the Patient Global Impression of Change (PGIC) Questionnaire at EOMT Using LOCF Data45 participants
GEn 2400 mg/DayNumber of Participants Who Are Responders on the Patient Global Impression of Change (PGIC) Questionnaire at EOMT Using LOCF Data35 participants
GEn 3600 mg/DayNumber of Participants Who Are Responders on the Patient Global Impression of Change (PGIC) Questionnaire at EOMT Using LOCF Data39 participants
Secondary

Time to Onset of Sustained Improvement in the 24-hour Average Pain Intensity Score

Sustained improvement in the 24-hour average pain intensity score is defined as at least 2 consecutive days on which the 24-hour average pain intensity score is \>=2 points less than the mean 24-hour average pain intensity score at baseline. Time to onset is measured from baseline and was calculated as the first day of event minus the last day of baseline and is expressed in days. Baseline score is the calculated mean of the 24-hour average pain score for each participant during the last 7 days prior to randomization.

Time frame: Anytime post-baseline until date of last dose of study medication (up to Week 13)

Population: ITT Population

ArmMeasureValue (MEDIAN)
PlaceboTime to Onset of Sustained Improvement in the 24-hour Average Pain Intensity Score49 days
GEn 1200 mg/DayTime to Onset of Sustained Improvement in the 24-hour Average Pain Intensity Score27 days
GEn 2400 mg/DayTime to Onset of Sustained Improvement in the 24-hour Average Pain Intensity Score10 days
GEn 3600 mg/DayTime to Onset of Sustained Improvement in the 24-hour Average Pain Intensity Score10 days

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026