EFFICACY AND SAFETY OF OXYBUTYNIN CHLORIDE TOPICAL GEL IN WOMEN WITH OVERACTIVE BLADDER: A RANDOMIZED, PLACEBO-CONTROLLED, DOUBLE-BLIND STUDY

Abstract

INTRODUCTION AND OBJECTIVES: Oxybutynin chloride topical gel (OTG) is a new 10% w/w ethanolic transdermal formulation of oxybutynin. The efficacy and safety of OTG vs placebo were assessed in a randomized, parallel-group, double-blind, placebo-controlled study (OG05009; 00350636 at ClinicalTrials.gov; conducted June 2006 to May 2007) in adults with overactive bladder (OAB). We report findings for the cohort of female participants. METHODS: Men and women 18 years of age with OAB and urge urinary incontinence (UI) were enrolled at 76 clinics of various types. Patients were randomized 1:1 to treatment with 1 g OTG or placebo applied once daily to rotating sites on the abdomen, upper arm/shoulder, and thigh for 12 weeks. The primary efficacy variable was change from baseline to study end (week 12 or last observation carried forward) in the mean number of daily UI episodes as recorded in a 3-day bladder diary. Analysis of covariance was used to compare efficacy results for the OTG and placebo groups. Adverse events (AEs) were monitored throughout the study. RESULTS: All randomized patients (N=789) were included in the efficacy and safety analyses; 352 patients in each treatment group were female. Mean age of female patients was 59 years; 610/704 (87%) were white. OTG treatment in women resulted in significantly greater improvements than did placebo in mean change in daily incontinence episodes and in the secondary outcome variables of daily urinary frequency and urinary voided volume (Table). At study end, complete urinary continence was achieved by 27.0% (95/352) of women treated with OTG vs 15.6% (55/352) treated with placebo. Dry mouth was the most frequent treatment-related anticholinergic AE and occurred more often with OTG (7.4%, 26/352) than with placebo (2.8%, 10/352); no patient withdrew because of dry mouth. Pruritus was the most frequent application site reaction (ASR) and occurred in 2.3% (8/352) of women treated with OTG and 0.9% of those (3/352) treated with placebo. Two women treated with OTG and 1 treated with placebo withdrew primarily because of ASRs. No serious treatment-related AEs occurred. CONCLUSIONS: OTG was well tolerated and effective at improving OAB symptoms in women with OAB and urge UI.