Answer: When it’s too hard to find.

The filing of a inter partes review (“IPR”) petition seeking to invalidate an opponent’s patent is a favorite strategy of defendants in patent infringement litigations. Why? Because the common wisdom is that the judges who adjudicate IPR’s are far more likely to invalidate a  patent’s claims for obviousness than a lay jury in a District Court litigation. The statistics bear this out.

However, there are traps for the unwary awaiting petitioners in IPR’s. One of them is that the burden of establishing that an article (as opposed to a prior art patent) constitutes a “printed publication” capable of being considered as prior art is on the petitioner.  See Medtronic, Inc. v. Barry, 891 F.3d 1368, 1380 (Fed. Cir. 2018) (“Medtronic, the patent challenger, bears the burden of establishing that a particular document is a printed publication”). Meeting this burden is not as straightforward as some might believe.

Take, for example, a paper that was published as one of many papers in a multi-volume compendium of the proceedings of a technical society meeting. Suppose you have the following facts:

  • The paper itself bears a date that is several years before the filing date of the patent under attack.
  • The entire multi-volume set of proceedings also bears an early enough publication date.
  • It can be proven that physical copies of the multi-volume set of proceedings were on the shelves of several libraries before the filing date of the patent under attack.
  • It can be proven that the entire set of proceedings, including the paper in question, was available on line before the filing date of the patent under attack.
  • The specific paper in question had been cited by several other authors before the filing date of the patent under attack.

This would clearly be a prior art “printed publication” that could be used to attack the patent, right?

Not necessarily.

The key question is whether the paper was “publicly accessible.” “’Public accessibility’ has been called the touchstone in determining whether a reference constitutes a ‘printed publication’….” Acceleration Bay, LLC v. Activision Blizzard, Inc. 908 F. 3d 765, 772 (Fed. Cir. 2018).  Proving that a paper was publicly accessible requires more than mere proof that it was sitting on a library shelf, available on line or even that other authors had found it.  Rather, a reference is considered publicly accessible only if it was “disseminated or otherwise made available to the extent that persons interested and ordinarily skilled in the subject matter or art, exercising reasonable diligence, can locate it.” Id.

Well, there’s always Google, isn’t there? Surely one could have found this paper by entering a search string relevant to the subject matter of the patent under attack into Google, and if the paper in question turned up among the search results, that’s the end of that, right?

Again, not necessarily.

As we all know, it is not unusual for Google searches to return tens of thousands, hundreds of thousands, or even millions of hits. Note that Acceleration Bay refers to “reasonable diligence.” In Acceleration Bay the Federal Circuit noted that “There is no public accessibility where the proposed search would require the interested artisan to be skimming through potentially hundreds of titles.” Acceleration Bay at 773. Based on that language it can be argued that a Google search that turned up hundreds of thousands of hits would not have enabled an interested person to find the paper in question with “reasonable diligence.”

As with all other aspects of patent litigation, the drafting of an IPR petition requires careful thought and attention to detail.