(Adds comment from Sandoz, Amgen, background on litigation)
By Andrew Chung
NEW YORK, Sept 2 (Reuters) - A U.S. appeals court has cleared the way for Novartis AG to launch the first biosimilar drug in the United States as it declined on Wednesday to stop the sale of the company's copycat version of Amgen Inc's blockbuster cancer drug Neupogen.
The U.S. Court of Appeals for the Federal Circuit in July said Novartis could begin to market its biosimilar drug, to be sold under the name Zarxio, after Sept. 2.
Amgen had sought an injunction while both companies ask the court to clarify federal regulations on when close copies of biologic medicines may be brought to market. The appeals court, based in Washington, gave no reasons for rejecting Amgen's bid.
Novartis's generic drugs unit, Sandoz, has said in court papers that it can begin to market Zarxio commercially on Thursday.
Sandoz said it welcomed Wednesday's decision but would not give further details on an exact launch date.
Amgen spokeswoman Kelley Davenport said the company was proud of helping millions of patients over the past 24 years with Neupogen. She said Amgen "will utilize our capabilities to compete effectively."
Amgen sued Sandoz last October, alleging infringement of a patent on Neupogen, its $1.2 billion-a-year medicine that boosts white blood cell counts to fight infections in cancer patients.
While biosimilars aim to copy biologic products, which are made inside living cells, they are not considered exact duplicates, such as generic versions of more traditional pills.
Insurers hope biosimilars will cost the public 40 percent to 50 percent less than the original brands.
Siegmund Gutman, an attorney at Proskauer Rose in Los Angeles, who has followed the case but was not involved, said Sandoz has not offered pricing information on Zarxio and any reduction in cost to patients remains uncertain.
"The marketplace is a complicated environment. We'll just have to see how it plays out," he said.
Biosimilars, including a version of Neupogen, have been available in Europe since 2006.
July's decision by the Federal Circuit said that federal law governing biosimilars required Novartis to wait six months after the Food and Drug Administration approved the drug to begin to market it. That approval came in March.
Both companies have asked for a rehearing on that decision. Amgen said the court wrongly interpreted the law, while Novartis argued it unfairly delayed the entry of Zarxio on to the market, harming cancer patients, taxpayers, and insurers.
(Reporting by Andrew Chung; Editing by Alexia Garamfalvi, Jonathan Oatis and Bernard Orr)