Effects of voluntary dose escalation in a placebo-controlled, flexible-dose trial of fesoterodine in subjects with overactive bladder.

Aims: To characterize the response to fesoterodine treatment for overactive bladder (OAB) in subjects who did or did not choose to dose escalate in a flexible-dose study.

Methods: Subjects were randomized to fesoterodine 4  mg or placebo. At week 2, subjects could remain on 4  mg (non-escalators) or choose to increase to 8  mg (escalators) for the remaining 10 weeks (sham escalation for placebo). Subjects completed 3-day bladder diaries at baseline, week 2 and week 12 noting micturitions, urgency episodes, and urgency urinary incontinence (UUI) episodes.

Results: Sixty-three per cent of 438 subjects randomized to fesoterodine and 73% of 445 randomized to placebo dose escalated. At baseline, fesoterodine escalators had significantly more micturitions and urgency episodes than fesoterodine non-escalators (P < 0.001); at week 2, before dose escalation, diary-dry rate and improvement in micturitions and urgency episodes were significantly greater among fesoterodine non-escalators versus escalators (P < 0.001); and by week 12, after dose escalation, diary-dry rate and improvements in micturitions and UUI episodes were similar between fesoterodine non-escalators and escalators (P > 0.05). The placebo escalator group did not demonstrate a similar response over placebo non-escalators following the dose escalation decision point.

Conclusion: A rapid and robust response to fesoterodine 4  mg was demonstrated in non-escalators. Subjects who chose to dose escalate to fesoterodine 8  mg at week 2 showed significant improvement by week 12 versus baseline and week 2 (prior to escalation), as well as versus placebo. Dose escalation to 8  mg fesoterodine provided subjects with efficacy and tolerability similar to those who were satisfied with the 4-mg dose.