Novartis announced a deal to sell the US rights to

the overactive bladder treatment Enablex (darifenacin) to Warner Chilcott in a deal valued at up to $420 million. The two companies currently co-market the drug in the country after Warner Chilcott gained rights through last year's acquisition of Procter & Gamble's pharmaceuticals division.

Under the agreement, the Swiss drugmaker will receive an upfront payment of $400 million from Warner Chilcott, and a further $20 million in potential milestone payments. Warner Chilcott will manufacture the drug once the transaction is completed, which is expected by the end of October, Novartis said.

Enablex was approved by the FDA in 2004 for the treatment of overactive bladder and was launched in early 2005. Global sales of the drug reached $223 million last year

.