Drug OK to boost Astellas in leaky bladder market

Japanese drugmaker Astellas Pharma got what it was hoping for and what it badly needs, FDA approval of its new bladder treatment, mirabegron, branded Myrbetriq.

The potential market is large. Estimates of Americans suffering from overactive bladders range from 33 million to 44 million. But Astellas also needs a new source to offset revenue that will peter out when its current bladder treatment, Vesicare falls off patent. That bladder control drug generated $1 billion in sales last year but loses its shield in 2018. Astellas reportedly is aiming to reach $1.9 billion in sales from both Vesicare and Myrbetriq by the end of its fiscal year that ends in March 2015.

Myrbetriq goes up against Pfizer's ($PFE) Detrol, Warner Chilcott's ($WCRX) Enablex, and of course Astellas' own Vesicare. The advantage of the once-daily drug is that it helps people with leaky bladders without affecting their ability to urinate, like some competing drugs, Bloomberg reports. That said, the FDA laid out a fairly substantial list of risks in its approval announcement.

There is increased blood pressure and heart risk. Also some patients experienced hypersensitivity reactions like anemia and painful rashes. There also is a link to liver disease, some urinary tract infections and even malignant tumors. The FDA says the reason for the tumor risk is unknown. Myrbetriq is not recommended for anyone with uncontrolled high blood pressure, end-stage kidney disease or severe liver disease.

The company says it expects to have the new drug to pharmacies by the fourth quarter.

- here's the Bloomberg story
- get more from Reuters
- see the FDA notice