April 30 (Bloomberg) -- Teva Pharmaceutical Industries Ltd., the world's largest maker of generic drugs, and rival Apotex Inc. lost their court fight to immediately begin selling copies of Pfizer Inc.'s blood pressure medicine Norvasc.

Mylan Laboratories Inc. retains the right to be the exclusive seller of the drug for now, though it lost its battle to prevent Apotex from entering the market before September. All three companies were appealing a portion of a U.S. Food and Drug Administration decision over the market for amlodipine besylate, the chemical name for Norvasc.

``These three companies maintain that the FDA rulings which favor them are valid while the rulings which disadvantage them are erroneous,'' U.S. District Judge Ricardo Urbina in Washington said in a ruling posted today on the court's Web site. None of the companies have demonstrated ``a substantial likelihood of success on the merits,'' he said.

The drug was Pfizer's second-biggest product last year, with U.S. sales of $2.7 billion. Mylan entered the market the day after a March 22 appeals court ruling that invalidated Norvasc's patent.

Mylan, based in Canonsburg, Pennsylvania, was the first to challenge the patent and the only company to get FDA approval, and so argued it has exclusive rights for six months. Closely held Apotex countered that it should be the only generic-drug company in the market because it won the appeals court decision. Teva claimed that, since key provisions of the patent were invalidated, everyone should be allowed into the market.

Confusion

The confusion arose because the patent expired March 25, three days after the court ruling. New York-based Pfizer had been given an additional six months of exclusive rights, until September, for agreeing to test the drug's effects on children.

The FDA said that, since the patent expired, Mylan wasn't entitled to the six-months of exclusive rights for being the first to challenge the patent. However, the agency also ruled that, since only a portion of the Norvasc patent was invalidated, only Apotex could benefit from the appeals court decision.

That meant other companies like Teva that didn't already have FDA approval would have to either win a court case or wait until Pfizer's six-month period ends in September.

Denise Bradley, a spokeswoman for Petah Tikva, Israel-based Teva, declined to comment. Apotex is based in Weston, Ontario. Apotex spokesman Steve Giuli and Mylan spokesman Patrick Fitzgerald didn't immediately return messages seeking comment.

After the patent was invalidated and Mylan entered the market, Pfizer began selling its drug without the label as an ``authorized generic'' through its Greenstone unit. Lipitor for cholesterol is Pfizer's top-selling drug.

Shares of Mylan fell 12 cents to $21.93 in composite trading on the New York Stock Exchange. They have risen 10 percent this year, giving the company a market value of $5.28 billion. Shares of Pfizer fell 15 cents to $26.46. Teva fell 120 shekels to 15,470 ($3,947) in Tel Aviv.

The case is Mylan Laboratories Inc. v. Leavitt, 07cv579, U.S. District Court, District of Columbia (Washington).

To contact the reporters on this story: Susan Decker in Washington at sdecker1@bloomberg.net; Jeff St.Onge in Washington at jstonge@bloomberg.net.

Last Updated: April 30, 2007 16:44 EDT