SAN FRANCISCO -- In probably the most closely watched battlebetween biotech competitors, a U.S. District Court on Tuesdayheard opening arguments in the patent infringement suit byXoma Corp. against Centocor Inc.

Gerald Sobel, lead counsel for Berkeley, Calif.-based Xoma,told the six-member jury that Xoma would show that U.S.patent No. 4,918,163, issued to the University of California in1990 and licensed exclusively to Xoma, is valid and thatCentocor is infringing the patent.

The companies are fighting for the market to treat gram-negative sepsis, a bacterial infection that can lead to septicshock and death. Some estimates put the U.S. market for thesetherapies in excess of $750 million annually. Xoma claims tohave invested $70 million to develop E5, while Centocor saysit has spent $100 million on Centoxin.

At issue are claims 6 and 7 of Xoma's patent, which describe amethod of treating humans with gram-negative infections.Xoma said the patent covers antibodies that bind to the samesite on the bacteria to which its E5 monoclonal antibody binds.Centocor's Centoxin belongs to that family of antibodies, Sobelsaid.

"The case isn't about whether (Centoxin) and E5 are differentproducts," Sobel said. "The case is about whether (Centoxin)satisfies claim 7. It's like traveling in an automobile. Itdoesn't matter if it's a Ford or a Chevy."

Donald Dunner, lead counsel for Malvern, Pa.-based Centocor,countered that Xoma's patent is far narrower. "Xoma isstretching its patent out of all proportion to its originalbounds," he said. Dunner said Xoma's patent covers only E5 andclose relatives of E5. Centoxin "is different than E5 and has adifferent result in therapy. Centocor isn't running in the samerace as Xoma," Dunner concluded.

Part of the dispute centers on whether the invention wasobvious, given prior work in the area. Centocor argues thatpublications by Elizabeth Ziegler in 1982 and Nelson Teng in1985 made obvious the invention of what ultimately became E5by Dr. Lowell Young of UCLA.

Xoma says the articles were cited as prior art in the patentapplication and were considered by the patent examiner.Neither showed how to treat humans, which Young was thefirst to do, Sobel said.

Judge Robert H. Schnacke has ordered both sides not tocomment on the case during the trial, which may last intoSeptember.

Xoma stock (NASDAQ:XOMA) closed down $1.50 at $25.75 onTuesday. Centocor (NASDAQ:CNTO) closed down 50 cents at$36.25.

-- Karen Bernstein BioWorld Staff

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