The daily pain intensity is an 11-point numerical rating scale ranging from 0 (no pain) to 10 (worst possible pain).

The analysis set (N=610) is the intention-to-treat population, which was defined as all randomized subjects

A responder is defined by the Sponsor as a randomized subject who completes the double-blind Randomized Treatment Period and experiences improvement in the Week 12 Weekly Pain Score from Screening Pain Score. This includes the proportion of responders with at least 30% and at least 50% reduction in pain intensity.

The PGIC assesses the change in overall status relative to the initiation of the treatment. The scale measures global change of overall status on a 7-point scale (1 = No change (or condition has got worse), 2 = Almost the same, 3 = A little better, 4 = Somewhat better, 5 = Moderately better, 6 = Better, 7 = A great deal better). The proportion of subjects responding " A great deal better " and "better" was summarized by treatment group.

The MOS Sleep Scale measure sleep parameters contains 12 items. Eleven of them scored using a 5-point response scale and across 5 dimensions of sleep, including disturbance (4 items), sleep problems index (9 items), somnolence (3 items), adequacy (2 items), and respiratory impairments (2 items). The original survey items are converted to a 0 to 100 range (by Converting 1 to 0, 2 to 25, 3 to 50, 4 to 75, and 5 to 100). Items in each dimension (disturbance, sleep problems index, somnolence, adequacy, respiratory impairments) of sleep are averaged together to create the score for the scale. The range of each sleep dimension is from 0 to 100. Higher score of sleep disturbance, somnolence, sleep indices, and respiratory impairments indicates relatively worse sleep problem, whereas lower scores for sleep adequacy indicate worse sleep problems.

The MOS Sleep-R was analyzed and presented as a change from Screening Baseline to Week 12 in double blinded treatment period. Subjects who discontinued from treatment early were not included in this analysis.

The 12 items of the MOS Sleep Scale measure sleep parameters across 6 dimensions of sleep, including disturbance (4 items), sleep problems index (9 items), quantity (1 item), somnolence (3 items), adequacy (2 items), and respiratory impairments (2 items). One of the 12 items, Sleep quantity, records the actual number of hours slept. Reported here is the sleep quantity.

The RMDQ contains 24 items that is used to quantify the impact of low back pain on subject's ability to perform daily activities, mood and sleep. The questionnaire consists of 24 statements derived from the Sickness Impact Profile, with the addition of the phrase "because of my back." The questionnaire covers the areas of mobility, self-care, and sleeping.

The RMDQ score is the total number of items checked which is from a minimum of 0 to a maximum of 24; the greater the score the grater the physical disability due to lower back pain.

The RMDQ was analyzed and presented as a change from Screening Baseline to Week 12 in double blinded treatment period. Subjects who discontinued from treatment early were not included in this analysis.