Safety and efficacy of flexible-dose fesoterodine in British subjects with overactive bladder: insights into factors associated with dose escalation.

INTRODUCTION AND HYPOTHESIS: This study evaluated the efficacy and safety of flexible-dose fesoterodine and factors associated with dose escalation in subjects with overactive bladder (OAB).
METHODS: In this 12-week, open-label study, 331 adults with OAB symptoms for ≥3 months, ≥8 micturitions and ≥3 urgency episodes per 24 h and who reported at least "some moderate" bladder-related problems were treated with fesoterodine 4 mg once daily for 4 weeks, with the option to escalate to 8 mg for the remaining 8 weeks based on discussion of efficacy and tolerability with the investigator. Factors influencing dose escalation were identified using stepwise logistic regression. Efficacy was assessed via 3-day bladder diaries and patient-reported outcomes.
RESULTS: Of the subjects, 59 % dose escalated at week 4; 93 % of escalators cited insufficient clinical response. The decision to escalate was most often made by the subject (alone or with the investigator). Improvements from baseline were observed in diary and patient-reported outcomes at weeks 4 and 12. Smaller improvements in micturition frequency and worse bladder-related problems at week 4 were significantly associated with increased likelihood of dose escalation; baseline micturition frequency, age, sex, body mass index, antimuscarinic-associated adverse events and OAB symptom duration were not. Non-escalators had greater improvement from baseline to week 4 than escalators; by week 12, improvement was similar among escalators and non-escalators. Fesoterodine was well tolerated.
CONCLUSIONS: Treatment with flexible-dose fesoterodine improved bladder diary and patient-reported outcomes. Lower clinical response was related to dose escalation; after escalation, response in escalators approached that of non-escalators.