According to the Astellas, Mirabegron is a once daily oral ß3-adrenoceptor agonist discovered and developed by the company. Mirabegron enhances the urine collection function by activating ß3-adrenoceptor on the bladder’s smooth muscles and the relaxing bladder, and improves symptoms associated with OAB such as urgency, urinary frequency, and urge urinary incontinence.
Astellas claimed that the Phase 3 study in Japan met its objective by demonstrating efficacy in mirabegron treatment groups in mean change from baseline in number of micturitions per 24-hour (primary endpoint) compared to placebo. Also, based on the safety results in Phase 3 study, mirabegron appears to be safe and well tolerated and the incidence of anti-cholinergics side effects, such as dry mouth, was low and comparable to those in the placebo group.
Astellas is developing mirabegron as a global project. The results of the Phase 3 studies in the US and Europe were in line with those of the Japanese Phase 3 study and appear sufficient for regulatory submission. In Asia there is an ongoing multiregional Phase 3 study in China, Korea, Taiwan, and India.
Astellas expects to provide an additional option to the current standard anti-cholinergics including its Vesicare, and further contribute to OAB treatment by introducing into the Japanese market mirabegron with a different mechanism of action from anti-cholinergics.