A California US District Court, which had to re-open the dispute after an appeals court failed to deliver a verdict on two key points of contention, has backed the company's process patents for PCR. But it did not overturn a prior ruling which found that Roche's patents on Taq polymerase, an enzyme widely used in PCR, was unenforceable owing to alleged inequitable conduct by the Swiss firm.
Last year, the European Patent Office upheld a broad swathe of Roche's process patents, including those covering Taq polymerase.
Both the US and European actions were brought by Promega, a US-based laboratory supply company. And Roche is planning to proceed with a countersuit against Promega seeking substantial financial damages - likely in the millions of dollars - for what it alleges was the latter company's unlawful attempts to induce its customers to break their Roche PCR licences.
PCR is a nucleic acid amplification technology that allows minute amounts of genetic material to be amplified into billions of copies in just a few hours, facilitating the detection of the DNA or RNA of pathogenic organisms even before antibodies to these organisms are formed. It is also used in biological research and drug target discovery efforts.
Lanny Davis of Orrick Herrington & Sutcliffe, Roche's outside counsel, downplayed the significance of the Taq patent, noting that the enzyme is substitutable by a number of catalysts.
There was nobody at Promega prepared to discuss the outcome of the case, but a prepared statement from the company made much of the fact that the Taq patent had been deemed unenforceable and of Roche's alleged inequitable conduct.
"This decision upholds the integrity of scientific innovation," said Randall Dimond, vice president and chief technical officer of Promega.
"Over a decade of legal obstacles couldn't hide the fact that the US Patent Office was deceived by intentional misrepresentation and outright fabrication to gain an economic monopoly. The decision is unequivocal and definitive. It goes beyond simply clearing Promega, as it means that scientists have been burdened with undue royalty costs in the purchase of Taq," said Dimond.
Promega said the court invited the company to submit further evidence on the enforceability of the PCR patents, and Dr Dimond noted that Promega intends to respond to the this invitation.