SAN FRANCISCO -- Cetus Corp. is like the Wright brothers, saidLynn H. Pasahow, counsel for the Emeryville, Calif., company.Others before them invented the airplane, but they figured outhow to make it fly.

Attorneys for Cetus and E.I. Du Pont de Nemours & Co. madeclosing arguments in U.S. District Court here on Thursday in thepatent infringement trial over Cetus' polymerase chain reaction(PCR) technology. The jury will begin its deliberations onMonday.

Judge Marilyn Hall Patel told the jury that the burden of proofrests with Du Pont. The Wilmington, Del., company contendsthat Cetus' '202 and '195 patents, issued in 1987, are invalidbased on "anticipation" and "obviousness."

Attorney E. Anthony Figg, representing Du Pont, told the jurythat the patents are invalid because they cover an inventionmade in the laboratory of H.G. Khorana at the University ofWisconsin a decade earlier and were published in three papers.

Cetus attorney Pasahow countered that scientists at Khorana'slab abandoned their research by 1975, and nothing further washeard about the process until Cetus' first publication in 1985."That gap is among the most compelling evidence in the case,"Pasahow said.

PCR technology allows billions of copies of any targeted genesequence to be generated in a few hours. Cetus estimates thePCR market at more than $1.5 billion.

-- Karen Bernstein BioWorld Staff

(c) 1997 American Health Consultants. All rights reserved.