by Dennis Crouch
This is an important case showing that inequitable conduct based upon failure to cite prior art will continue to be viable.
Aventis Pharma v. Hospira (Fed. Cir. 2012)
Aventis holds two patents that cover its branded chemotherapy drug Taxotere. According to the patent, the active drug is mixed with other ingredients to form a perfusion that can be injected intravenously without causing anaphylactic or alcohol intoxication symptoms.
In litigation to prevent Hospira from bringing a generic form to market, the district court ruled the patents unenforceable for inequitable conduct during prosecution of the patents. On appeal, the Federal Circuit has affirmed that holding. This case marks the first time that the appellate court has upheld an inequitable conduct finding since raising the standard of proof in the 2011 Therasense v. BD en banc decision.
Inequitable conduct occurs when a patent applicant intentionally and materially misleads the patent office. Both intent and materiality must be proven. In Therasense, the court additionally held that materiality is normally only satisfied if the misconduct was a "but-for" cause of the given patent being issued. (Caveat for egregious misconduct).
This case involves the most typical inequitable conduct allegation: failing to notify the USPTO of a known reference that impacts patentability.
Lets walk through the steps of materiality and intent:
Materiality: In addition to inequitable conduct, the court also held a few of the patent claims invalid as obvious – relying upon the withheld reference. According to the court, this fact alone proves materiality – since the reference rendered the claim invalid. Two procedural issues add to this conclusion: (1) Claims are (according to the law) more narrowly construed at trial than at the USPTO and therefore references that are material at trial would have definitely been material at the USPTO. (2) Invalidation requires clear and convincing evidence but proof of materiality for inequitable conduct only requires a preponderance of the evidence. As such, information that works to prove the higher standard would certainly work to prove the lower standard.
Intent: To win, the defendant must show that the defendant had specific intent deceive. This can be proven by inference, but only if that conclusion is the "single most reasonable inference able to be drawn from the evidence." Here, the inventor testified that he saw the references as explaining failed experiments and therefore need not be disclosed to the PTO. However, the judge found that the inventor lacked credibility and that some evidence suggested the inventor had learned valuable information from the reference.
On appeal, the court confirmed that these elements were met and that the patents were therefore obtained through inequitable conduct.