Solifenacin as Add-on Therapy for Overactive Bladder Symptoms in Men Treated for Lower Urinary Tract Symptoms-ASSIST, Randomized Controlled Study

OBJECTIVES To assess the efficacy and safety of solifenacin add-on therapy to tamsulosin in lower urinary tract symptoms (LUTS) men with residual overactive bladder (OAB) symptoms despite tamsulosin monotherapy. METHODS In this randomized, multicenter, double-blind study, male LUTS patients aged >= 50 years with urgency episodes/24 hours >= 2 and micturitions/24 hours >= 8 were randomized to 3 groups: 12-weeks tamsulosin plus placebo (TAM + PBO), tamsulosin plus solifenacin 2.5 mg (TAM + SOL), and tamsulosin plus solifenacin 5 mg (TAM + SOL). Changes from baseline to end of treatment in the number of urgency episodes/24 hours (primary endpoint), micturitions, nocturia, urgency incontinence episodes, International Prostate Symptom Scores (IPSS), and Overactive Bladder Symptom Score (OABSS) were compared between the TAM + SOL groups and TAM + PBO. Safety was assessed on adverse events, postvoid residual volume, and maximal urinary flow rate (Q(max.)). RESULTS Six-hundred thirty-eight men were randomized. Urgency was reduced by 2.2 and 2.4 episodes in the TAM + SOL 2.5 and 5 mg groups, respectively. The TAM + SOL 5 mg group showed significant improvement compared with TAM + PBO (-2.4 vs -1.9, P = .049). The number of micturitions in both TAM + SOL groups were significantly reduced compared with TAM + PBO (both P < .001). IPSS storage symptom score and OABSS significantly improved in both TAM + SOL groups compared with TAM + PBO. Changes in IPSS voiding symptom score and Q(max.) were similar in all groups. Four patients (1.9%) in the TAM + SOL 5 mg group had urinary retention, but all recovered after catheterization. CONCLUSIONS In male LUTS patients with residual OAB symptoms despite tamsulosin monotherapy, TAM + SOL showed efficacy on urgency, which represents OAB symptoms and was well tolerated. UROLOGY 78: 126-133, 2011. (C) 2011 Elsevier Inc.