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Efficacy and safety of mirabegron versus placebo add-on therapy in men with overactive bladder symptoms receiving tamsulosin for underlying benign prostatic hyperplasia: A randomized, phase 4 study (PLUS)

  • Steven A. Kaplan,
  • Sender Herschorn,
  • Kevin T. McVary,
  • David Staskin,
  • Christopher Chapple,
  • Steve Foley,
  • Javier Cambronero Santos,
  • Rita M. Kristy,
  • Nurul Choudhury,
  • John Hairston,
  • Carol R. Schermer
Department of Urology, Icahn School of Medicine at Mount Sinai, New York City, New York, USA Department of Surgery/Urology, University of Toronto, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada Department of Urology, Stritch School of Medicine, Loyola University Medical Center, Maywood, Illinois, USA Division of Urology, St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, Massachusetts, USA Department of Urology, Royal Hallamshire Hospital, Sheffield, UK Department of Urology, Royal Berkshire Hospital, Reading, UK Department of Urology, Infanta Leonor Hospital, Madrid, Spain Astellas Pharma Global Development Inc., Northbrook, Illinois, USA Astellas Pharma Europe Ltd., Chertsey, UK

Purpose:

PLUS investigated the efficacy and safety of mirabegron add-on therapy in men with overactive bladder (OAB) symptoms receiving tamsulosin for underlying lower urinary tract symptoms attributable to benign prostatic hyperplasia (BPH).

Materials and Methods:

In this Phase 4 study, a 4-week, tamsulosin 0.4 mg run-in period was followed by a 12-week, randomized, double-blind, treatment period in which patients initially received mirabegron 25 mg or placebo add-on therapy. At 4 weeks, doses were titrated to mirabegron 50 mg or placebo equivalent. Efficacy endpoints: changes from baseline to end of treatment in mean number of micturitions/day (primary), mean volume voided (MVV)/micturition, number of urgency episodes/day, Total Urgency and Frequency Score (TUFS), and total International Prostate Symptom Score (IPSS; secondary). Safety: treatment-emergent adverse events (TEAEs) and post-void residual (PVR) volume and maximum urinary flow (Q max) assessments.

Results:

Of 676 men, most were ≥65 years old (380 [56.2%] patients). Tamsulosin plus mirabegron (TAM+MIRA) was statistically superior to tamsulosin plus placebo (TAM+PL) in reducing the mean number of micturitions/day (–2.00 versus –1.62, adjusted difference: –0.39, 95% confidence interval: –0.76, –0.02). Statistically superior results were noted for TAM+MIRA in MVV/micturition, urgency episodes/day, and TUFS (not IPSS). Higher overall TEAE rates were observed with TAM+PL, although higher rates of drug-related TEAEs were noted with TAM+MIRA. Urinary retention rates were higher in the TAM+MIRA group. PVR volume and Q max results were not clinically meaningful.

Conclusions:

The results of PLUS underscore the utility of mirabegron add-on therapy to treat men with OAB symptoms receiving tamsulosin for BPH.