Apotex fights Teva exclusive on hypertension drugs

WASHINGTON, March 31 (Reuters) - Apotex Inc has challenged the U.S. Food and Drug Administration's decision to give rival Teva Pharmaceutical Industries Ltd (TEVA.TA) six months of exclusive marketing for generic versions of the widely-used blood pressure medicines Hyzaar and Cozaar.

Apotex filed a lawsuit on Tuesday against the FDA and its parent agency, the Department of Health and Human Services, arguing that a relevant patent for the medicine had expired and that no company was eligible for the exclusive rights.

The challenge follows an earlier court battle in which Teva had won its own legal fight to market the generic forms of the drugs exclusively for six months after the manufacturer Merck & Co Inc (MRK.N) had requested that the patent be delisted.

Apotex said notwithstanding that court decision issued earlier this month, the patent had expired so the FDA's "decision erroneously assumes that the FDA may deviate from the clear intent of Congress with regard to patent expiration."

Apotex has filed its own application with the FDA to offer generic versions of the drugs and said in the court filing that it was prepared to compete with Teva if it received approval on April 6.

FDA spokeswoman Karen Riley said the agency does not comment on pending litigation. A spokeswomen for Teva declined to comment.

The two drugs had combined worldwide sales of $3.6 billion in 2009, of which U.S. sales were about $1.5 billion, according to Teva.

While branded drugs can lose as much as 80 percent of revenues once generic versions flood the market, the erosion is typically slower when just one generic competitor steps in.

The exclusivity period is usually awarded to the first company that files with U.S. health regulators seeking approval for a generic drug, and that lets the company charge a bit more for its drug before competition forces cheaper pricing.

Apotex asked the U.S. District Court for the District of Columbia to nullify the FDA's decision favoring Teva and issue a restraining order to prevent the company from receiving a six-month exclusive marketing period for the medicines. (Reporting by Jeremy Pelofsky; additional reporting by Lisa Richwine, editing by Tim Dobbyn)