Mirabegron in combination with solifenacin significantly reduced overactive bladder (OAB) symptoms, in a small preliminary study from Japan. This was an open label study with no placebo arm, over a relatively short time period of 16 weeks of treatment. So the results must therefore be interpreted with caution. Clearly, combination therapy represents a promising development in the medical treatment of the symptoms of overactive bladder. Formal, double blind, randomised controlled trials are shortly due to report and it will be interesting to see if these findings are replicated in a more rigorous trial setting. More importantly, the results will need to be analysed to see if improvements in symptoms are clinically significant to patients in order to justify the addition of a further long-term therapy, and a significant increase in the cost of medical treatment.