A good week for Astellas has ended with the US Food and Drug Administration giving the green light to the Japanese drugmaker's overactive bladder treatment Myrbetriq.

An extended-release tablet taken once daily, Myrbetriq (mirabegron) improves the storage capacity of the bladder by relaxing the bladder muscle during filling. The approval was expected given that the FDA's Reproductive Health Drugs Advisory Committee voted 7 to 4 in favour, with one abstention, in April.

The approval is based on three trials. involving 4,116 patients. Results showed that Myrbetriq 25mg and 50mg effectively reduced the number of times a patient urinated and the number of times a patient had wetting accidents during a 24-hour period. Those taking Myrbetriq 50mg also expelled a greater amount of urine, demonstrating the drug’s effectiveness in improving the storage capacity of the bladder, the FDA said.

Victoria Kusiak, deputy director of the Office of Drug Evaluation III in the FDA’s Center for Drug Evaluation and Research, noted that some 33 million Americans suffer from OAB, "which is uncomfortable, disrupting and potentially serious.” She added that the approval "provides a new treatment option for patients with this debilitating condition".

Approved in Japan in July last year, as Betanis, mirabegron is a first-in-class beta-3 adrenoceptor agonist. Astellas already markets an OAB treatment, the blockbuster Vesicare (solifenacin).

Enzalutamide filed in Europe for prostate cancer

The news came just after Astellas announced the submission of a marketing authorisation application to the European Medicines Agency for its much-touted advanced prostate cancer drug enzalutamide (also known as MDV3100).

Specifically the filing, which follows a similar submission to the US Food and Drug Administration, seeks approval for the novel, once-daily oral androgen receptor signalling inhibitor for the treatment of men with metastatic castration-resistant prostate cancer who have been previously treated with docetaxel-based chemotherapy.

The submission follows positive results from the Phase III AFFIRM study, which confirmed that enzalutamide demonstrated a statistically significant improvement in overall survival with a median improvement over placebo of 4.8 months. Astellas has also unveiled further data from AFFIRM showing treatment with enzalutamide resulted in a significantly higher response rate in health-related quality of life as compared to placebo (43.2% vs. 18.3%),

In addition, the median time to occurrence of the first skeletal-related event in enzalutamide-treated patients was 16.7 months compared to 13.6 months with placebo. The drug has been developed with partner Medivation.