Pregabalin Versus Placebo In The Treatment Of Neuropathic Pain Associated With HIV Neuropathy

Mean pain score was defined as the mean of the last 7 daily diary pain ratings. Participants rated their Human Immunodeficiency Virus (HIV) neuropathy pain over the past 24 hours on an 11-point numeric rating scale ranging from 0 = no pain to 10 = worst possible pain. A rating of 1-3 was considered as mild pain; 4-6 = moderate pain; and 7-10 = severe pain. Endpoint was the last observation for a participant assessed using specified imputation method, modified Baseline Observation Carried Forward (mBOCF).

Time frame: Baseline, Endpoint (up to Week 16)

Population: Intent to Treat (ITT) population: all randomized participants who took at least 1 dose of study drug. Imputation: mBOCF, baseline data was carried forward for participants who discontinued due to adverse events or had no post-baseline observations; otherwise last observation carried forward (LOCF).

WPAI: 6-question participant rated questionnaire to determine the degree to which SHP affected work productivity while at work and affected activities outside of work. It assesses amount of absenteeism, presenteeism and daily activity impairment attributable to a HIV neuropathy pain. Question 2 and 3 assesses absenteeism as: Hours of work missed in past 7 days due to leg/foot pain or other reason, respectively. Question 4 assesses presenteeism as: Hours of work performed in past 7 days. A participant who had responded 'no' to question 1 regarding employment status reported hours of work and as this was a self-reported questionnaire the source data were included.

Time frame: Baseline, Week 16, 17

Population: ITT population: all randomized participants who took at least 1 dose of study drug. N (number of participants analyzed) signifies those participants who were evaluable for this measure. n = participants evaluable for this measure at specified time points for each arm group, respectively.

SF-36 is a standardized survey evaluating 8 domains of functional health and well being: physical and social (So) functioning (Fn), physical and emotional role (role-physical \[R-P\], role-emotional \[R-E\]) limitations, bodily pain (BP), general health (GH), vitality (Vit), mental health (MnH). Two summary scores include Physical Component (Ph C) and Mental Component (Mn C). The score for a section is an average of the individual question scores. Score range for domain scores and summary scores: 0-100 (100=highest level of functioning).

Time frame: Baseline, Endpoint (up to Week 16)

Population: ITT population: all randomized participants who took at least 1 dose of study drug. n = participants evaluable for this measure at specified time points for each arm group, respectively. Missing data for endpoint (up to Week 16) imputed using LOCF.

BPI-sf:5-item self-administered questionnaire to assess severity,impact of pain on daily functions. Pain Severity Index (PSI):average of Question 1-4 each measured severity of pain over past 24-hours on 11-point scale (0=no pain to 10=worst possible pain). Pain Interference Index (PII):average of 7 pain interference items of Question 5 that measured level of interference of pain on daily function on 11-point scale (0=does not interfere to 10=completely interferes). For PSI, PII range:0-10 higher score=higher pain/interference. Endpoint=last observation for participant as per imputation method.

Time frame: Baseline, Week 4, 8, 12, 16, Endpoint (up to Week 16)

Population: ITT population: all randomized participants who took at least 1 dose of study drug. N (number of participants analyzed) signifies those participants who were evaluable for this measure. n = participants evaluable for this measure at specified time points for each arm group, respectively. Missing data for endpoint (up to Week 16) imputed using LOCF.

HADS: participant rated questionnaire with 2 subscales. HADS-A assesses state of generalized anxiety (anxious mood, restlessness, anxious thoughts, panic attacks); HADS-D assesses state of lost interest and diminished pleasure response (lowering of hedonic tone). Each subscale comprised of 7 items with range 0 (no presence of anxiety or depression) to 3 (severe feeling of anxiety or depression). Total score 0 to 21 for each subscale; higher score indicates greater severity of anxiety and depression symptoms. Endpoint was the last observation for a participant assessed using imputation method.

Time frame: Baseline, Endpoint (up to Week 16)

Population: ITT population: all randomized participants who took at least 1 dose of study drug. n = participants evaluable for this measure at specified time points for each arm group, respectively. Missing data for endpoint (up to Week 16) imputed using LOCF.

Participant-rated 12-item questionnaire to assess constructs of sleep over past week; 7 subscales: sleep disturbance (range 0-100), snoring (range 0-100), awaken short of breath (SOB) or with headache (range 0-100), sleep adequacy (range 0-100), somnolence (range: 0-100); sleep quantity (range: 0-24), optimal sleep (yes/no), and 9 item index measures of sleep disturbance provide composite scores: sleep problems index (range 0-100). Except adequacy, optimal sleep and quantity, higher scores=more impairment. Endpoint was the last observation for a participant assessed using imputation method.

Time frame: Baseline, Endpoint (up to Week 16)

Population: ITT population: all randomized participants who took at least 1 dose of study drug. n = participants evaluable for this measure at specified time points for each arm group, respectively. Missing data for endpoint (up to Week 16) imputed using LOCF.

NPSI: participant-rated questionnaire to evaluate different symptoms of neuropathic pain. It includes 10 descriptors and 2 temporal items. Results reported for the 10 descriptors (burning, squeezing, pressure, electric shocks, stabbing, light touching of area, pressure of area, cold of area, pins and needles, tingling) quantified on a 0 (no symptoms) to 10 (worst symptoms imaginable) scale. Endpoint was the last observation for a participant assessed using specified imputation method.

Time frame: Baseline, Endpoint (up to Week 16)

Population: ITT population: all randomized participants who took at least 1 dose of study drug. n = participants evaluable for this measure at specified time points for each arm group, respectively. Missing data for endpoint (up to Week 16) imputed using LOCF.

NPSI: participant rated questionnaire to evaluate different symptoms of neuropathic pain (subscales: burning \[superficial\] spontaneous pain, pressing \[deep\] spontaneous pain, paroxysmal pain, evoked pain, and paresthesia/dyesthesia \[P/D\]). Includes 10 descriptors quantified on a 0 (no symptoms) to 10 (worst symptoms imaginable) and 2 temporal items assessing duration of spontaneous ongoing and paroxysmal pain. The relevant subscales and total score were transformed to 0-1, higher score indicates a greater intensity of pain. Endpoint=last observation for participant as per imputation method.

Time frame: Baseline, Endpoint (up to Week 16)

Population: ITT population: all randomized participants who took at least 1 dose of study drug. n = participants evaluable for this measure at specified time points for each arm group, respectively. Missing data for endpoint (up to Week 16) imputed using LOCF.

Weekly current pain score was defined as the mean of the daily current pain diary ratings split into 7 day intervals. Participants rated current (right now) HIV neuropathy pain an 11-point NRS ranging from 0 = no pain to 10 = worst possible pain. A rating of 1-3 was considered as mild pain; 4-6 = moderate pain; and 7-10 = severe pain. Endpoint was the last observation for a participant assessed using specified imputation method.

Time frame: Baseline, Week 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, Endpoint (up to Week 16)

Population: ITT population: all randomized participants who took at least 1 dose of study drug. n = participants evaluable for this measure at specified time points for each arm group, respectively. Missing data for endpoint (up to Week 16) imputed using LOCF.

Weekly mean sleep interference score was defined as the mean of the daily sleep interference diary ratings split into 7 day intervals. Participants rated how HIV neuropathy pain has interfered with their sleep during the past 24 hours on an 11-point NRS ranging from 0 = does not interfere with sleep to 10 = completely interferes (unable to sleep due to pain). Endpoint was the last observation for a participant assessed using specified imputation method.

Time frame: Baseline, Week 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, Endpoint (up to Week 16)

Population: ITT population: all randomized participants who took at least 1 dose of study drug. N (number of participants analyzed) signifies those participants who were evaluable for this measure. n = participants evaluable for this measure at specified time points for each arm group, respectively. Missing data for endpoint (up to Week 16) imputed using LOCF.

Time frame: Screening

Population: Data were not collected since this was a screening tool for investigators and there was no analysis planned for this measure.

MOS-SS: participant-rated 12 item questionnaire to assess constructs of sleep over past week. It included 7 subscales: sleep disturbance, snoring, awaken short of breath or with headache, sleep adequacy, somnolence, sleep quantity, optimal sleep, and 9 item index measures of sleep disturbance provide composite scores: sleep problems index. Participants responded whether their sleep was optimal or not optimal by choosing yes or no. Endpoint was the last observation for a participant assessed using imputation method.

Time frame: Baseline, Endpoint (up to Week 16)

Population: ITT population: all randomized participants who took at least 1 dose of study drug. n = participants evaluable for this measure at specified time points for each arm group, respectively. Missing data for endpoint (up to Week 16) imputed using LOCF.

NPSI: participant-rated questionnaire to evaluate different symptoms of neuropathic pain. It includes 10 descriptors, and 2 temporal items. Results reported for categorical change in temporal items assessed on 5-point scale for duration of spontaneous pain (1=continuously, 2=8-12 hours \[hrs\], 3=4-7 hrs, 4=1-3 hrs, 5=less than 1 hr), numbers of pain attacks (1=more than 20, 2=11-20 attacks, 3=6-10 attacks, 4=1-5 attacks, 5=no attack). Change data categorized as worsened (negative change), unchanged (no change), and improved (positive change). Endpoint=last observation as per imputation method.

Time frame: Baseline, Endpoint (up to Week 16)

Population: ITT population: all randomized participants who took at least 1 dose of study drug. N (number of participants analyzed) signifies those participants who were evaluable for this measure. n = participants evaluable for this measure at specified time points for each arm group, respectively. Missing data for endpoint (up to Week 16) imputed using LOCF.

WPAI: 6-question participant rated questionnaire to determine the degree to which specific health problem (SHP) affected work productivity while at work and affected activities outside of work. It assesses amount of absenteeism, presenteeism and daily activity impairment attributable to a HIV neuropathy pain. Number of participants who responded Yes/No to Question 1: Are you currently employed (working for pay)? are reported.

Time frame: Baseline, Week 16, 17

Population: ITT population: all randomized participants who took at least 1 dose of study drug. n = participants evaluable for this measure at specified time points for each arm group, respectively.

The CGIC scale measures a physician's global impression of a participant's clinical condition at final visit in terms of change relative to the start of treatment (CGIC). At final visit, the participants CGIC will be categorized into a three point scale as: improvement: CGI response of very much improved, much improved or minimally improved; no change: CGI response of no change; worsening: CGI response of very much worse, much worse or minimally worse. Number of participants in each category is reported.

Time frame: Week 16

Population: ITT population: all randomized participants who took at least 1 dose of study drug. N (number of participants analyzed) signifies those participants who were evaluable for this measure.

PGIC: participant rated instrument to measure participant's change in overall status on a 7-point scale; range from 1 (very much improved) to 7 (very much worse). Number of participants in each category is reported.

Time frame: Week 16

Population: ITT population: all randomized participants who took at least 1 dose of study drug. N (number of participants analyzed) signifies those participants who were evaluable for this measure.

Percentage of time above sedentary level is number of epochs (60 seconds) with greater than (\>) 200 activity counts per minute divided by total number of epochs during the day (non sleep period) multiplied by 100. This was determined by actigraphy. Actigraphy was performed with an accelerometer that was worn on the wrist like a watch. It was programmed to record movements while the device was being worn. Endpoint was the last observation for a participant assessed using specified imputation method.

Time frame: Baseline (Day -14 to 1), Week 1 through Week 4, Week 12 through Week 16, Endpoint (up to Week 16)

Population: ITT population. N (number of participants analyzed) = participants evaluable for this measure. Missing data for endpoint (up to Week 16) imputed using LOCF. Data for Baseline (Day -14 to 1), Week 1 through Week 4, Week 12 through Week 16 were collected and reported in individual participant listings but not statistically summarized for analysis.

WPAI: 6-question participant rated questionnaire to determine the degree to which SHP affected work productivity while at work and affected activities outside of work. It assesses amount of absenteeism, presenteeism and daily activity impairment attributable to a HIV neuropathy pain. Question 5 and 6 assesses: How much leg/foot pain affect productivity and daily activity, respectively in past 7 days? on 11-point scale, where 0 (not affected/no impairment) to 10 (completely affected/impaired).

Time frame: Baseline, Week 16, 17

Population: ITT population: all randomized participants who took at least 1 dose of study drug. n = participants evaluable for this measure at specified time points for each arm group, respectively.

Sleep efficiency is the time spent asleep divided by total time between sleep onset and sleep end, multiplied by 100. Sleep efficiency was determined by actigraphy. Actigraphy was performed with an accelerometer that was worn on the wrist like a watch. It was programmed to record movements while the device was being worn. Endpoint was the last observation for a participant assessed using specified imputation method.

Time frame: Baseline (Day -14 to 1), Week 1 through Week 4, Week 12 through Week 16, Endpoint (up to Week 16)

Population: ITT population. N (number of participants analyzed) = participants evaluable for this measure. Missing data for endpoint (up to Week 16) imputed using LOCF. Data for Baseline (Day -14 to 1), Week 1 through Week 4, Week 12 through Week 16 were collected and reported in individual participant listings but not statistically summarized for analysis.

SFI is a measure to quantify sleep restlessness. SFI calculated from analysis of the periods that participant was not moving (immobile bouts). It is number of immobile bouts that were exactly 1 minute long divided by total number of immobile bouts. Value ranges from 0-100 percent, with low number representing more restful sleep. SFI determined by actigraphy. Actigraphy was performed with an accelerometer that was worn on wrist like a watch. It was programmed to record movements while device was being worn. Endpoint was the last observation for a participant assessed using imputation method.

Time frame: Baseline (Day -14 to 1), Week 1 through Week 4, Week 12 through Week 16, Endpoint (up to Week 16)

Population: ITT population. N (number of participants analyzed) = participants evaluable for this measure. Missing data for endpoint (up to Week 16) imputed using LOCF. Data for Baseline (Day -14 to 1), Week 1 through Week 4, Week 12 through Week 16 were collected and reported in individual participant listings but not statistically summarized for analysis.

Activity counts are the units of motion. It is equal to the sum of peak accelerations each second during the epoch (60 seconds). Total activity counts per day is the sum of the activity counts for each epoch (60 seconds) during the day (non sleep period). A total activity count was determined by actigraphy. Actigraphy was performed with an accelerometer that was worn on the wrist like a watch. It was programmed to record movements while the device was being worn. Endpoint was the last observation for a participant assessed using specified imputation method.

Time frame: Baseline (Day -14 to 1), Week 1 through Week 4, Week 12 through Week 16, Endpoint (up to Week 16)

Population: ITT population. N (number of participants analyzed) = participants evaluable for this measure. Missing data for endpoint (up to Week 16) imputed using LOCF. Data for Baseline (Day -14 to 1), Week 1 through Week 4, Week 12 through Week 16 were collected and reported in individual participant listings but not statistically summarized for analysis.

Total sleep time is the number of minutes asleep between time of sleep onset to morning awakening and MIS is the number of minutes spent awake after sleep onset to final awakening. TST and MIS were determined by actigraphy. Actigraphy was performed with an accelerometer that was worn on the wrist like a watch. It was programmed to record movements while the device was being worn. Endpoint was the last observation for a participant assessed using specified imputation method.

Time frame: Baseline (Day -14 to 1), Week 1 through Week 4, Week 12 through Week 16, Endpoint (up to Week 16)

Population: ITT population. N (number of participants analyzed) = participants evaluable for this measure. Missing data for endpoint (up to Week 16) imputed using LOCF. Data for Baseline (Day -14 to 1), Week 1 through Week 4, Week 12 through Week 16 were collected and reported in individual participant listings but not statistically summarized for analysis.

Time frame: Screening, Week 1, 4, 8, 12, 16, 17

Population: Safety population included all participants who signed the informed consent, had exposure to study drug and had at least one safety assessment. n = participants evaluable for this measure at specified time points for each arm group, respectively.

MINI: short structured clinical interview to make diagnoses of psychiatric disorders according to Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) or International Classifications of Disease-10 (ICD-10). In the MINI Modules, participants were asked a series of Yes/No questions.

Time frame: Screening

Population: Data for this pre-specified outcome measure was collected and reported in individual participant listings but not statistically summarized for analysis.

Laboratory tests included hematology, chemistry, cluster of differentiation 4 (CD4) count and cluster of differentiation 8 (CD8) count, HIV plasma viral load, B12, Venereal Disease Research Laboratory (VDRL), toxic screens for drugs and alcohol, reflex thyroid-stimulating hormone (TSH), urinalysis. Number of participants with a laboratory abnormality meeting specified criteria while on study treatment or during lag time was reported.

Time frame: Screening up to Week 17

Population: Safety population included all participants who signed the informed consent, had exposure to study drug and had at least one safety assessment. N (number of participants analyzed) signifies those participants who were evaluable for this measure.

A physical examination included an examination of the general appearance, skin, chest, pulses, pulmonary, cardiovascular, head, eyes, ears, nose, throat, abdominal, and extremities.

Time frame: Screening, Week 8, 17

Population: Safety population included all participants who signed the informed consent, had exposure to open label study drug and had at least one safety assessment. n = participants evaluable for this measure at specified time points for each arm group.

A neurological examination consisted of examination of the mental state, cranial nerve function, motor function (reflexes of patellar, achilles, biceps, babinski and coordination) and sensory function (sharp sensation of dorsal surface of right and left great toe, light touch of lower extremities \[LE\], right and left first metatarsal joint position sense, and vibration sensation \[vibration is felt for \< 6 seconds = markedly diminished, 6 to 10 seconds = mild loss, \> 10 seconds = normal\]).

Time frame: Screening

Population: Safety population included all participants who signed the informed consent, had exposure to study drug and had at least one safety assessment.

Serum pregnancy test (regardless of childbearing potential) and urine pregnancy test for all female participants were performed.

Time frame: Screening for serum pregnancy test, Week 1 for urine pregnancy test

Population: Data for this pre-specified outcome measure was collected and reported in individual participant listings but not statistically summarized for analysis.

PHQ-8: 8-item self-administered validated subset of PHQ-9, which comprises first 8 items of measure. Participant rated Over past 2 weeks, how often bothered by any of following problems?: little interest in doing things(1); feeling down(2); trouble falling or staying asleep/sleeping too much(3); feeling tired(4); poor appetite/overeating(5); feeling bad about self(6); trouble concentrating(7); moving or speaking slowly or being so fidgety/moving around more than usual (8). Each item scored on scale of 0(not at all)-3(nearly every day). Total score range: 0-24, higher score=greater severity.

Time frame: Screening

Population: ITT population: all randomized participants who took at least 1 dose of study drug. n = participants evaluable for this measure at specified time points for each arm group, respectively.

S-STS:8-item clinician/participant administered prospective rating scale to assess TE suicidal(Su) ideation(ID),behavior(BHV).Items 1a,2-6,7a,8 scored on 5-point Likert scale 0(not at all) to 4(extremely). Items 1,1b,7 require yes/no response. S-STS total score range 0-30. Lower score=reduced Su tendency. Responses on S-STS were mapped to Columbia Classification Algorithm of Suicide Assessment(C-CASA) as 1:Completed Su; 2: Su attempt; 3: Preparatory acts; 4: Su ID; 5: Self-injurious (SI) BHV, intent unknown; 6: Not enough information; 7: SI BHV, no Su intent; 8: Other, no deliberate self harm.

Time frame: Screening, Post-Baseline (Week 4 up to Week 17)

Population: Safety population included all participants who signed the informed consent, had exposure to study drug and had at least one safety assessment. n = participants evaluable for this measure at specified time points for each arm group, respectively.

An AE was any untoward medical occurrence attributed to study drug in a participant who received study drug. An SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent are events between first dose of study drug and up to 28 days after last dose that were absent before treatment or that worsened relative to pretreatment state.

Time frame: Baseline up to 28 days after last dose

Population: Safety population included all participants who signed the informed consent, had exposure to study drug and had at least one safety assessment.

Time frame: Screening, Week 1, 4, 8, 12, 16, 17

Population: Safety population included all participants who signed the informed consent, had exposure to study drug and had at least one safety assessment. n = participants evaluable for this measure at specified time points for each arm group, respectively.

Systolic Blood Pressure (SBP) is the blood pressure (pressure exerted by circulating blood on the walls of blood vessels) when heart is contracting; it is the maximum arterial pressure during contraction of left ventricle of heart. Diastolic Blood Pressure (DBP) is the blood pressure (pressure exerted by circulating blood on the walls of blood vessels) when heart is relaxing; it is the minimum arterial pressure during relaxation and dilation of ventricles of heart.

Time frame: Screening, Week 1, 4, 8, 12, 16, 17

Population: Safety population included all participants who signed the informed consent, had exposure to study drug and had at least one safety assessment. n = participants evaluable for this measure at specified time points for each arm group, respectively.