AUA 2019: Late-Breaking Abstract: Efficacy and Safety of Mirabegron vs. Placebo Add-on Therapy in Men with Overactive Bladder Symptoms receiving Tamsulosin for Underlying Benign Prostatic Hyperplasia (PLUS)

Chicago, IL (Urotoday.com) Overactive bladder (OAB) symptoms often overlap with those of benign prostatic hyperplasia (BPH) in men. According to the presenter, mirabegron is a current alternative to the antimuscarinic medications used for the treatment of OAB. Previous research looked at the combination of mirabegron and tamsulosin, which is prescribed for BPH. Studies demonstrated high efficacy of dual therapy compared to placebo.   The goal of the multicenter, Phase 4, randomized, double-blind trial was to evaluate the efficacy and safety of mirabegron vs. placebo for treating OAB symptoms in men concurrently receiving tamsulosin for LUTS due to underlying BPH.

Men aged 40 or older who’s been taking tamsulosin for 2 or more months were enrolled in the study in North America and Europe. Subjects received a run-in dose of 0.4 mg of tamsulosin for 4 weeks. Then they were randomized based on the results of a voiding diary and PSA levels to the 0.4 mg tamsulosin + placebo group or 0.4 mg tamsulosin + 50 mg mirabegron. Participants were followed for 12 weeks. Study endpoints included changes in a number of voids, mean number of urge incontinence episodes per day, and IPSS total score.

Total of 676 men were recruited to the trial. Table 1 reflects sample characteristics:

Table 1
AUA 2019 baseline disease characteristics

Study results demonstrate that tamsulosin + mirabegron significantly decreased mean number of voids per day compared to tamsulosin + placebo group (-0.39(-0.76, -0.02), p=0.039). Additionally, dual combination was associated with a significant change in a volume voided compared to the placebo group (Figure 1). Data demonstrate a statistically significant change in a number of urgency episodes per day in the intervention group.

Figure 1
AUA 2019 volume voided compared to the placebo group

Tamsulosin in combination with mirabegron showed favorable safety outcomes (Table 2). Overall, research indicates that mirabegron is superior in efficacy to placebo and can be a useful add-on to tamsulosin for men with LUTS related to BPH.

Table 2
AUA 2019 safety parameter

Presented by: Steven A. Kaplan, MD, FACS, Professor of Urology, Director, The Men's Health Program, Icahn School of Medicine at Mount Sinai, New York City, New York

Written by: Hanna Stambakio, BS, Clinical Research Coordinator, Division of Urology, University of Pennsylvania, @AStambakio at American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois
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