Promega Corp., a privately held supply company, announcedThursday that it is challenging the validity of the patent forTaq polymerase, the widely used DNA amplification enzyme,which Hoffmann-La Roche bought in 1991 for more than $300million from the former Cetus Corp.

Roche sued the Madison, Wisc., company in October 1992,alleging Promega overstepped the boundaries of its 1990license from Cetus, which allowed Promega to sell the enzymefor uses other than polymerase chain reaction (PCR). Taqpolymerase is used less frequently in DNA sequencing andlabeling.

Promega said it filed papers late Wednesday in U.S. DistrictCourt in New Jersey seeking to amend its answer to Roche'ssuit.

"We're just a small company trying to defend ourselves," saidRandall Dimond, Promega's vice president and chief technicalofficer.

Following Roche's lawsuit, Dimond said, Promega decided torepeat published experiments and examples given in thepatent application.

"The evidence looked very conclusive to us that the patentshouldn't have issued," he said, pointing to "serious questions,"including ones pertaining to prior art. However, he declined togo into more detail. "It's kind of a David and Goliath. I don'texactly want to say what stones are in the sling," Dimond said.

"We are pretty confident that our patents are valid," counteredRoche spokeswoman Christine Aylward. She added that she hadnot seen the Promega filing.

On Monday, Promega served subpoenas on six individuals andRoche Molecular Systems to obtain information about U.S.Patent, No. 4,889,818, which was issued Dec. 26, 1989.

In December, Science magazine published a chart showing thatRoche's commercial provider, Perkin-Elmer, had 45 percent ofthe European market share for Taq polymerase in 1991, whilePromega had 25 percent -- at 40 percent of Perkin-Elmer'sprice. Perkin-Elmer markets the enzyme as AmpliTaq.

Other companies that had supplied the enzyme prior to theCetus patent, such as Life Technologies Inc. (BRL) andBoehringer Mannheim, also received licenses to continuesupplying it for non-PCR use, Dimond said, but have only 10percent and 8 percent of the European market, respectively,according to Science magazine. These larger companies havenot been accused of overstepping their licenses.

Promega contends that it has abided by license restrictionsnegotiated with Cetus, which include not advertising theenzyme for PCR use, but Dimond acknowledged the enzyme'slargest application is PCR. The customers are primarilyuniversity researchers, as well as government laboratories andsome corporate R&D labs.

Thomas Brock, a professor emeritus of bacteriology at theUniversity of Wisconsin-Madison, discovered the bacteriumfrom which the Taq enzyme was derived in 1966. "They(Hoffmann-La Roche) have a patent on the enzyme, which Ifind really amazing," Brock said in a statement released by theuniversity March 23. "This is a natural product from a naturalorganism. It has not been created by genetic engineering."

-- Nancy Garcia Associate Editor

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

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