A US federal judge has ruled that a key patent for an enzyme used in a DNA analysis technique is invalid and was obtained by fraud. The patent at issue—the '818 Taq patent—covers the native and recombinant forms of Taq DNA polymerase, a thermostable enzyme critical in polymerase chain reaction and gene sequencing owned by Hoffmann-La Roche (Nutley, NJ). Judge Vaughn Walker, who presides over the Northern District of California (San Francisco), upheld a challenge by Promega Corp (Madison, WI), which argued that scientists were originally awarded the patent after misrepresenting their experiments and falsely claiming advances over previous discoveries. Those scientists worked for the now defunct Cetus Corp, which sold the rights to the patent and a DNA replication process to Roche in 1991 for $300 million. Roche sued Promega in 1992 for breach of contract over a licensing agreement and the resulting dispute led to a four-week trial in February 1999.
"Roche remains convinced that our scientists conducted themselves with the utmost integrity and professionalism," Melinda Griffith, general counsel of Roche subsidiary Roche Molecular Systems said in a statement. However Judge Walker found that in eight separate instances the original patent holders at Cetus (who moved to Roche after 1991) intentionally withheld information and distorted facts; the judge's decision renders the primary Taq patent unenforceable.
The global market for sales of the enzyme is an estimated $200 million, and Roche and its licensing partner, Perkin-Elmer, rely on sales of licensed Taq to obtain PCR royalties. Unless overturned on appeal, the judge's ruling means that anyone can use the enzyme without paying Roche. La Roche officials say they plan to appeal the judge's decision.
