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

Abstract

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. 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 (Qmax.). 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 Qmax. were similar in all groups. Four patients (1.9%) in the TAM+SOL 5 mg group had urinary retention, but all recovered after catheterization. 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.