As of September 1, 2013, the PTAB has ruled on 166 petitions to initiate IPR proceedings. What have learned from these petitions? While there were some initial doubts on how the threshold for institution of IPR would be applied, the USPTO reports a whopping success rate of about 86% suggesting that petitioners are learning fairly quickly how to tip the scale of "reasonable likelihood" in their favor.

The PTAB has not rejected petitions simply because arguments presented in the petition were previously considered during prosecution. And IPRs have been instituted based on prior art that was previously considered by the USPTO. E.g., Macauto U.S.A. v. BOS GmbH & KG, IPR2012-00004, Paper 18 (Jan. 24, 2013). In fact, it is becoming abundantly clear that the PTAB is not hesitant to perform its own independent analysis, giving little or no deference to the examiner's findings during prosecution.

The majority of the trials have been instituted on obviousness grounds. Successful petitions have provided reasonable and well-articulated rationales for modifying or combining references and have carefully detailed how the proffered combination accounts for all the features of each challenged claim. In the context of anticipation, inherent disclosure of a claimed element by the prior art is perhaps the most challenging issue faced by petitioners. Successful petitions have clearly explained how the limitation is inherently present in the prior art through arguments and/or expert declarations.

Although expert declarations are not required for an IPR petition, most of the successful petitions have been accompanied by expert declarations. The PTAB gives considerable weight to expert declarations that are well supported by facts and technical information. A cogent and articulate declaration—in the expert's words and not mere repetition of attorney arguments—can be the tipping point for a successful IPR petition.

Failure to set forth claim construction positions can also influence the outcome of an IPR petition. If a petitioner fails to construe a claim term that the PTAB decides is necessary, the PTAB may either construe the term on its own or adopt the patentee's offered construction. As there is no guarantee that the PTAB will agree with their preferred construction, petitioners should consider how their unpatentability arguments might fare under any foreseeable construction.

In just one year, IPR petitions have become a popular option for challenging patents outside of litigation, and the "reasonable likelihood" standard has proven to be fairly straightforward and patent challenger-friendly. Potential challengers may find that the odds are indeed in their favor.

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