Patient-Reported Outcomes with the B3-Adrenoceptor Agonist Mirabegron in Phase III Trial in Patients with Overactive Bladder - Commentary

Overactive Bladder (OAB) is a condition with symptoms of urinary urgency, usually accompanied by frequency and nocturia, with or without urgency urinary incontinence1. OAB significantly interferes with daily routines and health-relate quality of life (HRQoL) in those who are affected. Along with treatments for OAB, the efficacy of OAB treatments has been traditionally assessed using bladder diaries during clinical trials, though not capturing patient’s quality of life or perception for treatment benefit. Fortunately, the use of validated reported outcomes (PROs), in addition with bladder diaries, allows both objective and subjective endpoints to be collected, which influences the impact of treatment and OAB on HRQoL2. Mirabegron, a B-adrenergic agonist drug, has been shown in a phase III trial to statistically reduce in number of incontinence episodes and micturitions3, however no PRO’s data collected was gathered. The aim of this study is then to assess PRO’s in patients receiving mirabegron.

Data was collected from the original multicentre, randomized, double-blind, parallel-group, placebo- and active-controlled phase III trial, SCORPIO3. The inclusion criteria were patients older than 18, and symptoms of OAB greater than 3 months. Patients who met enrollment criteria were then randomized to either oral placebo, mirabegron 50mg or 100mg/day, or tolterodine ER 4mg one daily for 12 weeks. The three PRO’s used in the study were: Treatment Satisfaction-Visual Analogue Scale (TS-VAS), Symptom Bother on the OAB Questionnaire (OAB-q), and Patient Perception of Bladder Condition (PPBC). Prespecified analysis and post-hoc analysis of changes in TS-VAS, OAB-q scores, and PPBC with mirabegron 50mg/day, tolterodine ER 4mg/day, and placebo were reported. Work productivity and activity impairment: specific health problem (WPAI-SHIP) instrument and incontinence pad use were also used to assess the effect of therapy on work productivity.

Out of the original 1,987 patients in the clinical trial, 1428 patients were included in the analysis of this study. The results of the study revealed significant improvements over placebo in OAB-q coping, concern and HRQoL total score were observed with mirabegron 50 mg/day. The PPBC analysis showed more patients significantly improved with both mirabegron 50mg/day and tolterodien ER 4mg/day relative to placebo, but no statistically significant major improvements. Mirabegron 50 mg/day produced higher reductions in absenteeism and overall work impairment, and improved presenteeism than in both placebo and tolderodine. Some limitations of the study included limited 12-week timeframe, and study was not powered for a head-to-head comparison of mirabegron and tolterodine.

In conclusion, 12 weeks of therapy with mirabegron at 50mg/day produces significant improvements in OAB-q and PPBC compared to placebo, and associated with numerical improvements in WPAI-SHIP scores and reduction in incontinence pad use at 4 weeks. These findings correlate with higher patient-reported perceptions and quality of life, whether or not they are incontinence baseline. Patients with OAB are expected to have greater benefit with mirabegron therapy compared to other treatments.

Read the Abstract

Authors: Vik Khullar, Gerard Amarenco, Javier C. Angulo, Mary Beth Blauwet, Jameel Nazir, Isaac A. Odeyemi, and Zalmai Hakimi

Affiliations: Urogynaecology Department, St Mary’s Hospital, Imperial College, London, United Kingdom, Department of Neuro-Urology, Sorbonne Universites, GREEN Group of Clinical Research in Neuro-Urology, Hopital Tenon, Assistance Publique-Hopitaux de Paris, Paris, France, Department of Urology, Hospital Universitario de Getafe, Universidad Europea de Madrid, Madrid, Spain, Astellas Pharma Global Development, Inc, Biostatistics, Northbrook, Illinois, Astellas Pharma Europe Ltd, Chertsey, United Kingdom, Astellas Pharma Global Development EU, Leiden, the Netherlands

Reference:

1. Haylen BT, de Ridder D, Freeman RM, et al. An International Urogynecological Association (IUGA)/International Continence Society (ICS) joint report on the terminology for female pelvic floor dysfunction. Neurourol Utodynam 2010;29:4–20.
2. . Coyne KS, Sexton CC, Irwin DE, et al. The impact of overactive bladder, incontinence and other lower urinary tract symptoms on quality of life, work productivity, sexuality and emotional well-being in men and women: Results from the EPIC study. BJU Int 2008;101:1388–95.
3. Khullar V, Amarenco G, Angulo JC, et al. Efficacy and tolerability of mirabegron, a b(3)-adrenoceptor agonist, in patients with overactive bladder: Results from a randomised European-Australian phase 3 trial. Eur Urol 2013;63:283–95.