The Inter Partes Review (IPR) procedure before the US Patent and Trademark Office allows a third party to have a granted patent reviewed for Protectability by the Patent Trial and Appeal Board (PTAB). However, once a decision has been reached in such proceedings, the patent cannot be challenged again on the same grounds. What happens if the attacker encounters a new critical citation after the proceedings have been concluded?

Praxair Distribution Inc. challenged INO Therapeutics’ patent US 8,846,112 B1 for the first time in 2015 on the grounds of lack of patentability of various claims. The IPR proceedings concluded with a decision that upheld certain claims. Following this decision, Praxair, together with NOxBOX, a UK subsidiary of Praxair, filed a new IPR proceeding based on a new citation “Greenough and Jaypee”. This citation had not been found earlier despite careful research.

The PTAB rejects the application as inadmissible (IPR 2016-00781 – http://www.aiablog.com/wp-content/uploads/2016/09/Praxair-Estoppel-at-PTAB.pdf). With careful research, Praxair could have found the citation in the earlier proceedings.

As evidence of exercising due diligence in searching the prior art, Praxair has only provided a “sample list of search results”. This list cannot substantiate the duty of care for several reasons. First, it is only a single search result. Secondly, neither the name nor the qualifications and experience of the searcher are given. Thirdly, it is not clear why the searcher used the chosen search terms and combinations of terms. Fourthly, there is no explanation as to whether the relevant citation was found by the Search and, if so, why it was not included in the “exemplary” list.

Moreover, Praxair itself has asserted elsewhere that the expert was looking for the “collective academic knowledge” of “Greenough and Jaypee” in the field of iNO therapy. An expert report by Dr. Lawson, which Praxair itself submitted, even states that the citation submitted is not an obscure document that a diligent searcher would not find. In addition, a professional interested in iNO therapy would refer to the publications of Anne Greenough, who is a pioneer in this therapy. Finally, there are various publications in which Greenough and Jaypee reference each other.

As the patent proprietor points out, the publication is available in various libraries and can be found using keywords from the patent in suit via Google Books. Various other publications by Greenough have also been cited in the patent family’s Examination Proceedings.

As a result, Praxair is merely attempting to support an earlier argument that the PTAB found to be irrelevant in the first decision.

Nor does it help that NOxBOX is an (additional) petitioner. It falls under the estoppel of 35 USC § 315(e) because, as a subsidiary, it is “a real party in interest or privy of the petitioner.”

Remark. The decision shows that you have to research very carefully and extensively before an IPR procedure, as you do not get a second chance to improve the arguments put forward. What is meant by “careful research” is very clear from the ruling. The criteria mentioned by the PTAB can be adopted as minimum requirements for a thorough search.

It also did not help Praxair that it brought its subsidiary on board as a co-attacker. The PTAB considers the interests of the subsidiary to be those of the parent company.

Links: IPR 2016-00781 – www.aiablog.com/wp-content/uploads/2016/09/Praxair-Estoppel-at-PTAB.pdf