By Will Boggs MD
NEW YORK (Reuters Health) - Mirabegron is more effective than placebo and as effective as most antimuscarinic monotherapies for treating patients with overactive bladder (OAB), according to an industry-funded systematic review and network meta-analysis.
"I think mirabegron is a good treatment for OAB, and if cost were not an issue, and if treating physicians were as familiar with its use as they are with antimuscarinics, it would be my first-line pharmacological treatment," Dr. Con Kelleher from Guys and St. Thomas' Hospital, in London, told Reuters Health by email.
Oral antimuscarinics have established efficacy in OAB, but many patients experience bothersome anticholinergic adverse effects. Mirabegron is also effective, with rates of adverse effects in clinical trials similar to those for placebo.
Dr. Kelleher and colleagues assessed the efficacy and tolerability of mirabegron 50 mg compared with antimuscarinic monotherapies and oral combination therapies in their meta-analysis of 64 randomized trials including more than 46,000 patients.
Mirabegron was significantly more effective than placebo and not significantly different from most antimuscarinics for reducing micturition frequency and urgency urinary incontinence, for improving dry rates and for reducing incontinence, the team reports in European Urology, online April 23.
Solifenacin monotherapy and the combination of solifenacin plus mirabegron were more effective than mirabegron monotherapy at reducing micturition frequency and incontinence.
Dry mouth and constipation were less common with mirabegron (which was similar to placebo) than with antimuscarinic monotherapy, the analysis shows. Urinary retention was more common with seven of the nine antimuscarinic treatments than with mirabegron.
"Combination therapy with solifenacin and mirabegron is more efficacious than either alone and may well be the way forwards in the future, maximizing efficacy and doing so with minimal side effects," Dr. Kelleher said.
Dr. Tom A. T. Marcelissen from Maastricht University Medical Center, in the Netherlands, who co-authored a linked editorial, told Reuters Health by email, "Because mirabegron has been shown to be equally effective as antimuscarinics, I think this agent should be considered in all patients with OAB. Antimuscarinics can have significant side effects and many patients abandon treatment. Therefore, mirabegron can be a good alternative."
"In some patients, for example, those with a high anticholinergic burden, mirabegron might even be considered first choice," he said. "Yet, the long-term effects of mirabegron on cardiovascular or cognitive function are not fully known, and therefore, some caution has to be taken, especially in the elderly."
Dr. Marcelissen added, "One should bear in mind that although the efficacy of various drugs for OAB has been proven in clinical studies, the actual improvement in incontinence episodes and voiding frequency are numerically small and perhaps not always clinically relevant. Hence, future trials should focus on patient-reported outcomes in order to adequately determine the effects on health-related quality of life."
Astellas Pharma, which markets mirabegron as Myrbetriq in the U.S., funded the trial, employed three of the authors and had various relationships with the rest, including Dr. Kelleher.
Eur Urol 2018.
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