Darren Donnelly, a partner in Fenwick’s patent litigation group, is quoted in a Law360 article titled “Inequitable Conduct a Dying Defense 2 Years Post-Therasense.”
In 2011, the federal circuit’s Therasense ruling held that overuse of the inequitable conduct defense had “plagued” the courts and accused infringers would be required to prove that patent holders were deliberately withholding information from the USPTO that would have impacted the office’s decision regarding patent claims.
"This court now tightens the standards for finding both intent and materiality in order to redirect a doctrine that has been overused to the detriment of the public.”
According to the article, a recent March cert petition by Sony Corp. “argues that the new standard improperly restricts the discretion of district courts to evaluate inequitable conduct.”
The article paraphrases Donnelly saying that Therasense did make it more difficult “to prove that nondisclosure of prior art amounts to inequitable conduct,” but it has made less of an impact on other types of conduct like “inequitable conduct claims over falsehoods in declarations to the patent office.”
Donnelly said, “Often the examiner allows the case because of what’s in the declaration, so it’s easier to allege ‘but for’ materiality,” and to prove that the act was intentional.
The full article is available through the Law360 website (subscription required).