The bladder pain severity was measured using 0-10 NPRS, with 0 representing 'no pain' and 10 representing 'the worst pain possible'. Participants were asked to select a number on the scale that best described the severity of bladder pain during past 24 hours over telephone using an interactive voice response system (IVRS) every evening at bedtime during the baseline assessment phase and treatment phase (up to 4 weeks). The primary analysis was conducted using a Mixed Model with Repeated Measures (MMRM) approach to calculate the Least Squares (LS) mean change from baseline in NPRS score and associated Standard Error (SE) at Week 4 for each treatment arm. Negative values indicate decrease in bladder pain severity.

Titration Completers Population - defined as participants who received at least 1 dose of drug, had at least 1 post-baseline NPRS Score, who titrated the dose in Week 1 of the treatment phase, and who completed the 4-week treatment phase

To assess the severity of bladder pain syndrome (BPS), an 8-item participant self-report PBIC-SD measure was used. Participants were asked to select a number on the scale that best described the severity of bladder pain over telephone using an IVRS each evening on the three consecutive days (during the Baseline Assessment Phase and during each Treatment Week up to 4 weeks). Each item was graded on a scale from 0 (good condition) to 4 (poor condition) with a total score range 0-32. Higher scores indicate more severe BPS. The analysis was conducted using a MMRM approach to calculate the LS mean change from baseline PBIC-SD total score and associated SE at Week 4 for each treatment arm. Negative values indicate decrease in severity of BPS.

Titration Completers Population - defined as participants who received at least 1 dose of drug, had at least 1 post-baseline PBIC-SD Score, who titrated the dose in Week 1 of the treatment phase, and who completed the 4-week treatment phase.

To measure the severity of BPS (urgency and frequency of urination, nighttime urination, and pain or burning) over past month, a 4-item self-report ICSI measure was used. Participants were asked to select a number on the scale that best described the severity of symptoms over telephone using an IVRS every evening at bedtime during the baseline assessment phase and treatment phase (up to 4 weeks). The ICSI score range from 0 (Not at all) to 5 (Almost always) for the first 3 items and a score of 0 (Not at all) to 4 (Almost always) for the last item, with an index score range of 0-19. Higher scores indicate more severe BPS. The analysis was conducted using one-way ANCOVA model to calculate the LS mean change from baseline ICSI total score and associated SE at Week 4 for each treatment arm. Negative values indicate decrease in severity of BPS.

Titration Completers Population - defined as participants who received at least 1 dose of drug, had at least 1 post-baseline ICSI Score, who titrated the dose in Week 1 of the treatment phase, and who completed the 4-week treatment phase.

To measure the degree of genitourinary pain symptoms, an 8-item self-report GUPI measure was used. Participants were asked to select a number on the scale that best described the severity of symptoms over telephone using an IVRS every evening at bedtime during the baseline assessment phase and treatment phase (up to 4 weeks). The GUPI instrument yields a total score of 0-45 and 3 subscales: pain (score = 0-23), urinary (score = 0-10), and quality of life (score = 0-12). Higher scores indicate more severe symptoms. The analysis was conducted using one-way ANCOVA model to calculate the LS mean change from baseline GUPI total score and associated SE at Week 4 for each treatment arm. Negative values indicate decrease in degree of genitourinary pain symptoms.

Titration Completers Population - defined as participants who received at least 1 dose of drug, had at least 1 post-baseline GUPI Score, who titrated the dose in Week 1 of the treatment phase, and who completed the 4-week treatment phase.