Amgen Inc. on Friday filed a complaint seeking a declaratoryjudgment that its granulocyte colony stimulating factor doesnot infringe U.S. patents held by Chugai Pharmaceutical Co. Ltd.and that the Chugai patents are invalid and unenforceable.

The complaint, filed in U.S. District Court in Washington, D.C., isdirected against two Chugai patents, No. 4,833,127, issued inMay 1989, and No. 5,043,156, issued in August 1991.

Chugai isn't selling or producing G-CSF in the United States, norhas the Tokyo company sued Amgen, said Amgenspokeswoman Sarah Crampton.

"This is an affirmative move in that we're seeking a judgmentthat we're not infringing," said Crampton. "We're very confidentof our overall patent position." She declined to commentfurther on Amgen's legal strategy.

Amgen shares (NASDAQ:AMGN) closed at $70, up $1.38. Theannouncement was made after the market closed.

Amgen's Neupogen received Food and Drug Administrationmarketing approval last February for preventing infectionsafter chemotherapy for cancers that do not arise from bonemarrow. Neupogen sales through Sept. 30 were $146 million.Analyst estimates for sales through Dec. 31 are between $210million and $240 million.

Amgen of Thousand Oaks, Calif., has two patents coveringrecombinant G-CSF. Patent No. 4,810,643, issued in March1989, and patent No. 4,999,291, issued in March 1991, bothcover the DNA, host cells, vectors and process for producingrecombinant G-CSF.

Chugai began sales of G-CSF in Japan in November. -- KarenBernstein

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