Prospective, double-blind, double-randomised, 2-arm parallel group study. Optimal dose increase. Primary efficacy assessment of OAB symptoms by patient diaries.

Inclusion Criteria:

• Patient is willing and able to complete the micturition diary correctly.
• Symptoms of overactive bladder (including urinary frequency, urgency with/without urge incontinence) for >= 3 months
• At least 3 episodes of urgency with or without incontinence in last 3 days
• At least three episodes of urgency with or without incontinence (PPIUS grade 3 or 4) during the 3-day micturition diary period
• Patient must experience frequency of micturition on average >= 8 times per 24-hour period during the 3-day micturition diary period

Exclusion Criteria:

• Pregnant women or women who intend to become pregnant during the study or women of childbearing potential who are sexually active and practising an unreliable method of birth control or will be lactating during the study. Reliable contraceptive methods are intra-uterine devices, contraceptive pills of combination type, hormonal implants and injectable or patch contraceptives
• Clinically significant outflow obstruction (at the discretion of the investigator)
• Significant post void residual volume (PVR>200ml)
• Significant stress incontinence or mixed stress/urge incontinence where stress is the predominant factor as determined by the investigator
• Patient with indwelling catheters or practising intermittent self-catheterisation
• Evidence of a symptomatic urinary tract infection, chronic inflammation such as interstitial cystitis, bladder stones, previous pelvic radiation therapy or previous or current malignant disease of the pelvic organs
• Hypersensitivity to solifenacin or to any of the excipients, uncontrolled narrow angle glaucoma, myasthenia gravis, urinary or gastric retention, severe renal impairment (GFR ≥30 ml/min), moderate or severe hepatic impairment, chronic intestinal disease, megacolon, requirement for dialysis, concomitant use of a strong CYP3A4 inhibitor, e.g. ketoconazole
• Non drug OAB treatment such as bladder-training, biofeedback and pelvic floor exercises are permissible if established at least 4 weeks prior to study start and intended to be continued throughout the study; electrostimulation therapy is not permissible at any time
• Use of drugs intended to treat urinary incontinence
• Diabetic neuropathy
• Any clinically significant condition, which in the opinion of the investigator makes the patient unsuitable for the trial
• Participation in any clinical trial within 30 days prior to randomisation
• Employees of the Yamanouchi Group, third parties associated with the study, or the study site
• Patient who did not complete the micturition diary according to the instructions