Back in my prosecution days, one lesson drilled into my head regarding prior art was “when in doubt about a reference’s materiality, send it to the Examiner and let him/her figure it out”. Fear of omitting a reference which could eventually invalidate an entire patent led to the practice of submitting any and all references to the USPTO. I recall shipping boxes upon boxes of references to the USPTO to get a checked IDS form in return, essentially my “get out of inequitable conduct” card.
On May 25, 2011, the Court of Appeals for the Federal Circuit issued its opinion in the case of Therasense v. Becton, Dickinson and Co. Writing for the majority, Chief Judge Rader clarified and narrowed the standard for inequitable conduct, relieving practitioners of at least some of their paranoia regarding information disclosure statements.
In their ruling, the Court decided that in order invoke the inequitable conduct defense, alleged infringers must show that the “applicant knew of the reference, knew it was material, and made a deliberate decision to withhold it.” To determine materiality, the Court described a “but-for” test, where the accused infringer must now show that the claim would not have issued but for the withheld information.
So how does this affect you as the applicant? Unfortunately, I doubt that you will see any immediate or significant decreases in legal fees resulting from less time spent on preparing and submitting Information Disclosure Statements. Attorneys are a careful bunch and most will still err on the side of caution. At least the risk of the nightmare scenario of an entire patent or patent series being invalidated because of a single omitted reference has been greatly reduced following this decision.