This study is to assess the efficacy and safety of YM178 in patients with symptoms of overactive bladder.

Inclusion Criteria:

• Subjects with symptoms of overactive bladder for at least 12 weeks before the study
• Subjects capable of walking to the lavatory without assistance and measuring the urine volume by him/herself
• Subject with an average frequency of micturition of 8 or more times per 24-hour period
• Subject with an average episode of urgency or urge incontinence of one or more times per 24-hours period
• Subject having provided written informed consent by him/herself

Exclusion Criteria:

• Subject having stress urinary incontinence as a predominant symptom
• Subject with transient symptoms suspected for overactive bladder
• Subject complicated with urinary tract infection, urinary stones, and/or interstitial cystitis or with a historical condition of recurrent urinary tract infection
• Subject complicated with bladder tumor/prostatic tumor or with the historical condition
• Subject confirmed to have a post-void residual volume of >=100ml or with a clinically significant lower urinary tract obstructive disease
• Subject with indwelling catheter or practicing intermittent self-catheterization
• Subject giving radiotherapy influencing urinary tract functions, or thermotherapy for benign prostatic hyperplasia
• Subject giving surgical therapy which may influence urinary tract functions within 24 weeks before the study
• Subject with uncontrolled hypertension (indicated by sitting SBP >=180mmHg or DPB >= 110mmHg)
• Subject with a pulse rate >= 110bpm or <50 bpm

Access to anonymized individual participant level data collected during the study, in addition to study-related supporting documentation, is planned for studies conducted with approved product indications and formulations, as well as products terminated during development. Studies conducted with product indications or formulations that remain active in development are assessed after study completion to determine if Individual Participant Data can be shared. Further details on Astellas' data sharing policy can be found at https://www.clinicaltrials.astellas.com/transparency/.

Access to participant level data is offered to researchers after publication of the primary manuscript (if applicable) and is available as long as Astellas has legal authority to provide the data.

Researchers must submit a proposal to conduct a scientifically relevant analysis of the study data. The research proposal is reviewed by an Independent Research Panel. If the proposal is approved, access to the study data is provided in a secure data sharing environment after receipt of a signed Data Sharing Agreement.