Mountain View-based Alza Corporation, a subsidiary of Johnson & Johnson, suffered a blow this week with the ruling by the Northern District of Virginia that Mylan Laboratories’s generic version of the overactive bladder treatment Ditropan XL did not infringe an Alza patent and that the Alza patent itself was invalid as anticipated and obvious.

Mylan was the first generic pharmaceutical company to file an Abbreviated New Drug Application (“ANDA”) for 5 mg and 10 mg of Oxybutynin, the active ingredient in Ditropan XL. Mylan will be eligible for 180 days of market exclusivity after it receives approval from the Food and Drug Administration (“FDA”). Earlier this year, Mylan received tentative approval for the drug from the FDA, which generally means that approval will be granted upon the resolution of any outstanding patent issues.

Alza has already announced that it intends to appeal the decision to the Court of Appeals for the Federal District in Washington, D.C.

The decision comes after Alza initiated another suit earlier this month, along with McNeil-PPC, Inc., against Hayward-based Impax Laboratories, Inc and Andrx Pharmaceuticals LLC in the United States District Court for the District of Delaware, alleging that defendants infringed their patents by seeking to make generic versions of Concerta prior to the expiration of the patents. Concerta is marketed as a treatment for attention deficit disorder (“ADD”) and attention deficit hyperactivity disorder (“ADHD”). The patents were issued in 2005 and cover the administration of the drug methylphenidate hydrochloride in an increasing concentration over a period of time. Plaintiffs argue that defendants’ drugs also cover the administration of the drug in an increasing concentration over a period of time, therefore infringing their patents. Genetic Engineering News has reported that sales of Concerta were $770 million in the 12 months ended in July, 2005.