Percentage of Participants Withdrawn From the Study During the Double-Blind Treatment Period By Reason
Percentage of participants who withdrew from the study during the double-blind treatment period. Withdrawal is due to any cause, including lack of efficacy.
Kaplan-Meier Estimates for Time to Discontinuation From the Study
Kaplan-Meier estimates for time to discontinuation from the study (due to any cause) was calculated as the number of days since participants were randomly assigned to study drug treatment, ie, the difference between the date the participants withdrew and the date participants were randomly assigned to study drug treatment. The censoring flag was set to 0 if a participant was withdrawn from study drug treatment early and was set to 1 if the participant completed the 12 week treatment period. Censoring time was calculated as the difference of treatment completion date (ie, date of last study drug administration) and date participant was randomly assigned to study drug treatment.
Participants With a Weekly Average Pain Intensity (wAPI) Increase From Baseline Exceeding 33%
The API over the previous 24 hours, based on the 11-point Numerical Rating Scale (NRS 11), was collected daily by e-diary. The wAPI scores from the previous 7 days were calculated for each study visit and averaged. The baseline wAPI score was calculated by averaging API scores from 3 to 12 days when the successful dose of hydrocodone extended release was confirmed at the end of the open label titration period, before patients were randomly assigned study drug.
The Numeric Rating Scale (NRS-11) is an 11-point scale for patient self-reporting of pain on a Likert-type scale in which 0 is no pain and 10 is the worst pain imaginable.
Participants With a Weekly Average Pain Intensity (wAPI) Increase From Baseline Exceeding 50%
The API over the previous 24 hours, based on the 11-point Numerical Rating Scale (NRS 11), was collected daily by e-diary. The wAPI scores from the previous 7 days were calculated for each study visit and averaged. The baseline wAPI score was calculated by averaging API scores from 3 to 12 days when the successful dose of hydrocodone extended release was confirmed at the end of the open label titration period, before patients were randomly assigned study drug.
The Numeric Rating Scale (NRS-11) is an 11-point scale for patient self-reporting of pain on a Likert-type scale in which 0 is no pain and 10 is the worst pain imaginable.
Weekly Average Pain Intensity (wAPI) Scores During the Double-blind Treatment Period
The API over the previous 24 hours, based on the 11-point Numerical Rating Scale (NRS 11), was collected daily by e-diary. The wAPI scores from the previous 7 days were calculated for each study visit and averaged. The baseline wAPI score was calculated by averaging API scores from 3 to 12 days when the successful dose of hydrocodone extended release was confirmed at the end of the open label titration period, before patients were randomly assigned study drug.
The Numeric Rating Scale (NRS-11) is an 11-point scale for patient self-reporting of pain on a Likert-type scale in which 0 is no pain and 10 is the worst pain imaginable.
Weekly Average Worst Pain Intensity (WPI) Scores During the Double-blind Treatment Period
The WPI was recorded by the patient in the e-diary daily throughout the study, based on the Numeric Rating Scale (NRS-11). Participants were asked to select the number that best described their WPI over the previous 24 hours. Values were averaged for each week.
The Numeric Rating Scale (NRS-11) is an 11-point scale for patient self-reporting of pain on a Likert-type scale in which 0 is no pain and 10 is the worst pain imaginable.
Clinician Assessment of Patient Function (CAPF) at Week 4
Clinicians assessed participants across 5 dimensions:
Patients general activities
Patients walking ability
Patients ability to work/perform activities of daily living
Patients relationships with others
Patients enjoyment of life
Assessments are rated on a 7-point scale, in which 1 is very much worsened and 7 is very much improved since the start of the study.
Clinician Assessment of Patient Function (CAPF) at Week 8
Clinicians assessed participants across 5 dimensions:
Patients general activities
Patients walking ability
Patients ability to work/perform activities of daily living
Patients relationships with others
Patients enjoyment of life
Assessments are rated on a 7-point scale, in which 1 is very much worsened and 7 is very much improved since the start of the study.
Clinician Assessment of Patient Function (CAPF) at Week 12
Clinicians assessed participants across 5 dimensions:
Patients general activities
Patients walking ability
Patients ability to work/perform activities of daily living
Patients relationships with others
Patients enjoyment of life
Assessments are rated on a 7-point scale, in which 1 is very much worsened and 7 is very much improved since the start of the study.
Clinician Assessment of Patient Function (CAPF) at Endpoint
Clinicians assessed participants across 5 dimensions:
Patients general activities
Patients walking ability
Patients ability to work/perform activities of daily living
Patients relationships with others
Patients enjoyment of life
Assessments are rated on a 7-point scale, in which 1 is very much worsened and 7 is very much improved since the start of the study.
Endpoint values are the last observed postbaseline data.
Patient Assessment of Function (PAF) at Week 4
The PAF is a self-administered questionnaire used to measure patients' assessment of their own ability to function in normal activities. Answers to the 7 questions were rated on a 7 point scale in which 1 was very much worsened and 7 were very much improved since the start of the study.
The seven functional areas are:
ability to go to work
ability to perform at work (includes both work outside the home and housework)
ability to walk
ability to exercise
ability to participate in social events
ability to have sex
ability to enjoy life
Patient Assessment of Function (PAF) at Week 8
The PAF is a self-administered questionnaire used to measure patients' assessment of their own ability to function in normal activities. Answers to the 7 questions were rated on a 7 point scale in which 1 was very much worsened and 7 were very much improved since the start of the study.
The seven functional areas are:
ability to go to work
ability to perform at work (includes both work outside the home and housework)
ability to walk
ability to exercise
ability to participate in social events
ability to have sex
ability to enjoy life
Patient Assessment of Function (PAF) at Week 12
The PAF is a self-administered questionnaire used to measure patients' assessment of their own ability to function in normal activities. Answers to the 7 questions were rated on a 7 point scale in which 1 was very much worsened and 7 were very much improved since the start of the study.
The seven functional areas are:
ability to go to work
ability to perform at work (includes both work outside the home and housework)
ability to walk
ability to exercise
ability to participate in social events
ability to have sex
ability to enjoy life
Patient Assessment of Function (PAF) at Endpoint
The PAF is a self-administered questionnaire used to measure patients' assessment of their own ability to function in normal activities. Answers to the 7 questions were rated on a 7 point scale in which 1 was very much worsened and 7 were very much improved since the start of the study.
The seven functional areas are:
ability to go to work
ability to perform at work (includes both work outside the home and housework)
ability to walk
ability to exercise
ability to participate in social events
ability to have sex
ability to enjoy life
Endpoint values are the last observed postbaseline data.
Clinician Global Impression of Severity (CGI-S) of Illness Scores During the Double-blind Treatment Period
The CGI-S is a clinician-rated scale that assesses the severity of the patient's pain condition and response to the treatment. Severity of illness, as related to moderate to severe pain, consists of the following 7 categories:
1 normal-shows no sign of illness,
2 borderline ill,
3 mildly (slightly) ill,
4 moderately ill,
5 markedly ill,
6 severely ill, and
7 among the most extremely ill (Guy 1976).
The clinician assesses the severity of the patient's condition, based on the clinician's total clinical experience with patients with this condition, in response to treatment.
Endpoint values are the last observed postbaseline data.
Short-Form Health Survey (SF-36) Physical and Mental Component Summary Scores at Baseline, Week 12 and Endpoint
SF-36 is a generic 36-item questionnaire measuring health-related quality of life (HRQL) covering 2 summary measures: physical component summary (PCS) and mental component summary (MCS). The SF-36 consists of 8 subscales. The PCS is represented by 4 subscales: physical function, role limitations due to physical problems, pain, and general health perception. The MCS is represented by 4 subscales: vitality, social function, role limitations due to emotional problems, and mental health. Participants self-report on items in a subscale that have between 2-6 choices per item using Likert-type responses (e.g. none of the time, some of the time, etc.). PCS and MCS scores are constructed as a T-score with a mean of 50 and standard deviation of 10 and no minimum or maximum score; higher scores indicate better health status.
Brief Pain Inventory - Short Form (BPI-SF) Pain Interference Mean Score During the Double-Blind Treatment Period
For pain interference, the BPI-SF used numerical scales to measure how much pain had interfered with 7 daily activities, including general activity, walking, work, mood, enjoyment of life, relations with others, and sleep in the past 24 hours. The scale used an 11 point Likert scale; range: 0 [does not interfere] to 10 [completely interferes]. BPI pain interference was typically scored as the mean of the 7 interference items. This mean could be used if at least 4 of 7 items had been completed on a given administration.
Participants With Adverse Events
An adverse event (AE) was defined in the protocol as any untoward medical occurrence that develops or worsens in severity during the conduct of a clinical study and does not necessarily have a causal relationship to the study drug. Severity was rated by the investigator on a scale of mild, moderate and severe, with severe= an inability to carry out usual activities. Relation of AE to treatment was determined by the investigator. Serious AEs include death, a life-threatening adverse event, inpatient hospitalization or prolongation of existing hospitalization, persistent or significant disability or incapacity, a congenital anomaly or birth defect, OR an important medical event that jeopardized the patient and required medical intervention to prevent the previously listed serious outcomes.
Participants With Potentially Clinically Significant Abnormal Vital Signs Values During the Double-Blind Treatment Period
Data represents participants with potentially clinically significant (PCS) vital sign values.
Significance criteria
Pulse - high: >=120 and increase of >= 15 beats/minute from baseline
Pulse - low: <=50 and decrease of >=15 beats/minute
Systolic blood pressure - high: >=180 and increase >=20 mmHg
Systolic blood pressure - low: <=90 and decrease >=20 mmHg
Diastolic blood pressure - high: >=105 and increase of >=15 mmHg
Diastolic blood pressure - low: <=50 and decrease of >=15 mmHg
Participants With Potentially Clinically Significant Abnormal Laboratory Values During the Double-Blind Treatment Period
Data represents participants with potentially clinically significant abnormal serum chemistry, hematology and urinalysis values.
Significance criteria:
Blood urea nitrogen: >=10.71 mmol/L
Uric acid: M>=625, F>=506 μmol/L
Hemoglobin: M<=115, F<=95 g/dL
Hematocrit: M<0.37, F<0.32 %
Urinalysis: blood (hemoglobin) and total protein: >=2 unit increase from baseline
Subjective Opiate Withdrawal Scales (SOWS) Scores During the Double-Blind Treatment Period
The results of the SOWS were collected in the e-diary daily during the first 4 weeks of the double blind treatment period and then during clinic visits at weeks 8 and 12 or early termination. The SOWS was a self administered questionnaire used to measure a participant's signs and symptoms of withdrawal from opiates. The scale contained 16 symptoms (eg, my nose is running; I feel restless), the participant rated the intensity on a scale of 0 (not at all) to 4 (extremely) for a total score of 0-64. The daily total score for the first 4 weeks was the largest score observed during the time period preceding that visit. For example, the week 1 score for each participant was the largest total score on any day between baseline and the night before the week 1 visit; the week 4 score for each participant was the largest score observed between the week 2 visit and the night before the week 4 visit.
Clinical Opiate Withdrawal Scales (COWS) Scores During the Double-Blind Treatment Period
The COWS was a clinician rated scale used to measure a participant's signs and symptoms of withdrawal from opiates, with ratings based only on apparent relationship to withdrawal. The COWS was performed at day 0 and weeks 1, 2, 4, 8, and 12 (double blind treatment period) or early termination. The scale contained 11 signs/symptoms whose intensity the clinician rated on a scale of 0 to 4 or 5.
A total score was calculated as the sum of the responses to the 11 signs/symptoms for a total range of 0-48. Withdrawal severity was classified, based on the total score, as follows:
0 to 4=normal
5 to 12=mild
13 to 24=moderate
25 to 36=moderately severe
>36=severe
Addiction Behavior Checklist (ABC) Total Scores During Both the Open-Label Titration and Double-Blind Treatment Periods
The ABC was a clinician rated scale that consisted of a brief (20 item) questionnaire designed to track behaviors characteristic of addiction related to prescription opioid medications in chronic pain populations. Items were focused on observable behaviors noted both during and between clinic visits. Each affirmative response was counted as one point, and points were added to calculate the total score, consequently resulting in scores ranging from 0 to 20 (0=no addiction-related behaviors seen and higher scores indicating an increasing number of addition-related behaviors seen).
The ABC was to be performed at visits 2 and 7 (beginning and end of Open-label Titration period) and weeks 1, 4, 8, and 12 (Double-blind Treatment period) or early termination.
Current Opioid Misuse Measures (COMM) Total Scores During Both the Open-Label Titration and Double-Blind Treatment Periods
The COMM was a clinician rated scale developed as a brief self report measure of current aberrant drug-related behavior for patients with chronic pain who were already on long term opioid therapy. A total score was calculated as the sum of the 17 questions. The total score ranged from 0 to 68. A score of 0 indicates no aberrant drug-related behaviors were seen. Patients with a total score of 9 or greater were classified as exhibiting aberrant drug-related behavior.
The COMM was to be performed at visits 2 and 7 (beginning and end of Open-label Titration period) and weeks 1, 4, 8, and 12 (Double-blind Treatment period) or early termination.
Change From Baseline to Endpoint in the Double-Blind Treatment Phase in Electrocardiogram (ECG) Parameters
A 12-lead ECG was conducted at baseline and the last visit during the double-blind treatment period (week 12, or early termination).