A Study of the Efficacy and Safety of Vibegron (MK-4618) in Participants With Overactive Bladder (OAB) (MK-4618-008)

A Phase IIb Randomized, Placebo- and Active Comparator (Tolterodine)-Controlled, 2-Part Clinical Study of the Efficacy and Safety of MK-4618 in Patients With Overactive Bladder A 52-week Extension to: A Phase IIb Randomized, Placebo- and Active Comparator (Tolterodine)-Controlled, 2-Part Clinical Study of the Efficacy and Safety of MK-4618 in Patients With Overactive Bladder

This is a 2-part study to assess if vibegron (MK-4618) reduces the number of daily urinations more effectively than placebo in participants with overactive bladder (OAB). The primary hypothesis of the base study is that administration of vibegron demonstrates a dose-related reduction, compared with placebo, in average number of daily micturitions in participants with OAB after 8 weeks of treatment.

All participants received placebo (run-in) for 1 week prior to randomization to Parts 1 and 2. Participants who complete the base study may be screened for a year-long, multicenter extension for assessment of long-term safety and efficacy.

Inclusion Criteria:

• If participant is of reproductive potential, must agree to remain abstinent or use (or have his/her partner use) 2 acceptable methods of birth control within the projected duration of the study
• Clinical history of OAB for at least 3 months and meets either the OAB wet or OAB dry criteria
• Is able to read, understand and complete questionnaires and voiding diaries without assistance
• Is ambulatory and in good general physical and mental health
• No clinically significant electrocardiogram or laboratory abnormality

Exclusion Criteria:

• If female, is currently pregnant or breast-feeding, or expecting to conceive within the projected duration of the study
• Evidence of diabetes insipidus, uncontrolled hyperglycemia or uncontrolled hypercalcemia
• Allergy, intolerance, or history of a significant clinical or laboratory adverse experience associated with any of the active or inactive components of tolterodine ER or vibegron (MK-4618) formulation; or has a history or active diagnosis of any condition contraindicated in the tolterodine ER prescribing label
• Has lower urinary tract pathology that could be responsible for urgency, frequency, or incontinence
• History of injury, surgery, or neurodegenerative diseases (e.g., multiple sclerosis) that could affect the lower urinary tract or its nerve supply
• History of continual urine leakage
• Surgery to correct stress urinary incontinence or pelvic organ prolapse within 6 months
• Known history of elevated postvoid residual
• Bladder training or electrostimulation within 2 weeks or is planning to initiate either procedure during the study
• Active or recurrent (>6 episodes per year) urinary tract infections
• Current hematuria
• Required use of an indwelling catheter or requires intermittent catheterization
• History of fecal incontinence