Trial Outcomes & Findings for A Phase 4 Study to Evaluate the Efficacy, Safety, and Tolerability of Mirabegron in Male Subjects With Overactive Bladder (OAB) Symptoms, While Taking the Alpha Blocker for Benign Prostatic Hypertrophy (BPH) (NCT NCT02656173)

Male participants with overactive bladder (OAB) under treatment with the α-blocker tamsulosin for benign prostatic hyperplasia (BPH) were enrolled in Japan (53 sites) and Korea (5 sites).

Eligible participants received tamsulosin 0.2 mg and placebo orally once a day after breakfast for 4 weeks. Subsequently, participants who met the eligibility criteria at the end of this 4 week screening period were randomized 1:1 to mirabegron 50 mg group or placebo group with tamsulosin 0.2 mg orally once a day after breakfast for 12 weeks.

Full analysis set (FAS) consisted of all participants who were randomized and received ≥ 1 dose of double-blind study drug and had a baseline micturition measurement and ≥ 1 post-baseline micturition measurement.

A micturition was defined as any voluntary micturition (excluding incontinence only episodes). The mean number of micturitions per 24 hours was calculated from data recorded by participants on a 3-day micturition diary before each visit.

A micturition was defined as any voluntary micturition (excluding incontinence only episodes). The mean number of micturitions per 24 hours was calculated from data recorded by participants on a 3-day micturition diary before each visit.

An urgency episode was defined as a complaint of a sudden, compelling desire to pass urine, which is difficult to defer. The mean number of urgency episodes per 24 hours was calculated from data recorded by participants on a 3-day micturition diary before each visit.

An urgency incontinence episode was defined as any episode when both urgency and incontinence occurred concurrently. The mean number of urgency incontinence episodes per 24 hours was calculated from data recorded by participants on a 3-day micturition diary before each visit.

An incontinence episode was defined as the complaint of any involuntary leakage of urine. The mean number of incontinence episodes per 24 hours was calculated from data recorded by participants on a 3-day micturition diary before each visit.

A nocturia episode was defined as a micturition episode initiated between night time. Night time was defined as the period between sleep onset time and the wake-up time the following day (micturitions at the same time as the wake-up time were excluded). The mean number of nocturia episodes per 24 hours was calculated from data recorded by participants on a 3-day micturition diary before each visit.

The mean volume voided per micturition was calculated from data recorded by participants on a 3-day micturition diary before each visit.

The OABSS is a 4-item questionnaire that assesses urinary frequency. Total score was the sum total of the score of each item (ranges: 0-15). Negative change means improvement.

Each OABSS subscale score was based on each question in the questionnaire: Daytime Frequency ("How many times do you typically urinate from waking in the morning until sleeping at night?" where scores range from 0-2), Nighttime Frequency ("How many times do you typically wake up to urinate from sleeping at night until waking in the morning?" where scores range from 0-3), Urgency ("How often do you have a sudden desire to urinate, which is difficult to defer?" where scores range from 0-5), Urgency Incontinence ("How often do you leak urine because you cannot defer the sudden desire to urinate?" where scores range from 0-5). A higher score is indicative of worse condition and a negative change from baseline indicates an improvement.

The IPSS included an 7-item questionnaire that assesses urinary frequency and incomplete voiding along with a QoL assessment. Total IPSS score was the sum total of the score (range: 0-35) of each item (Questions 1-7). Negative change means improvement.

IPSS subscale scores was calculated by following each formula. Storage subscale was derived as sum of scores for questions 2, 4, and 7 (range: 1-15). Voiding subscale-1 was derived as sum of scores for questions 3, 5, and 6 (range: 1-15). Voiding subscale-2 was derived as sum of voiding subscale-1 and the score for question 1 (range: 1-20). Individual scores and IPSS Quality of Life (QoL) score was the score of each item (range: 1-6) (Questions 1-7 and QoL item). A higher score is indicative of worse condition and a negative change from baseline indicates an improvement.

The OAB-q was a 33-item questionnaire, which consisted of an 8-item symptom bother scale and 25 health-related QoL items that form 4 subscales (coping, concern, sleep, and social interaction) and a total health-related QoL score. Symptom Bother was derived as sum of scores for questions 1-8 (range: 0-100). Higher Symptom Bother is indicative of greater symptom bother.

The OAB-q was a 33-item questionnaire, which consisted of an 8-item symptom bother scale and 25 health-related QoL items that form 4 subscales (coping, concern, sleep, and social interaction) and a total health-related QoL score. Total HRQL score was derived as sum of HRQL subscale scores (range: 25-150). Higher total HRQL score is indicative of better HRQL.

Treatment-emergent adverse events (TEAE) was defined as an adverse event (AE) with onset during the double-blind treatment period or an AE with onset during the screening period with worsening severity during the double-blind treatment period. The investigator assessed the severity of AEs as follows: Mild: No disruption of normal daily activities; Moderate: Affected normal daily activities; Severe: Inability to perform daily activities. A drug-related TEAE was a TEAE with at least a possible relationship to the study drug as assessed by the investigator. Serious TEAE was an AE considered serious.

PVR was measured by ultrasonography.

Urine flow rate was volume voided per micturition (voided volume) divided by time for the micturition (flow time).