Missed References from Patent Search Insufficient to Avoid Estoppel as PTAB Denies Institution of Second IPR | Practical Law

Missed References from Patent Search Insufficient to Avoid Estoppel as PTAB Denies Institution of Second IPR | Practical Law

In Praxair Distribution, Inc. v. INO Therapeutics LLC, the Patent Trial and Appeal Board (PTAB) denied Praxair's petition to institute an inter partes review (IPR) in view of an earlier IPR concerning the same patent because Praxair could have raised the new references that were the basis for the second petition in the first IPR, and its unpatentability arguments were substantially the same as those it presented in the previous IPR.

Missed References from Patent Search Insufficient to Avoid Estoppel as PTAB Denies Institution of Second IPR

by Practical Law Intellectual Property & Technology
Published on 01 Sep 2016 • USA (National/Federal)
In Praxair Distribution, Inc. v. INO Therapeutics LLC, the Patent Trial and Appeal Board (PTAB) denied Praxair's petition to institute an inter partes review (IPR) in view of an earlier IPR concerning the same patent because Praxair could have raised the new references that were the basis for the second petition in the first IPR, and its unpatentability arguments were substantially the same as those it presented in the previous IPR.
On August 25, 2016, in Praxair Distribution, Inc., v. INO Therapeutics LLC, the Patent Trial and Appeal Board (PTAB) denied Praxair's petition to institute an inter partes review (IPR) because Praxair was:
  • Estopped under 35 U.S.C. § 315(e)(1) from requesting or maintaining its petition to institute the IPR, because it could have raised the two references it relied on in the current petition during a previous IPR proceeding that it had requested and maintained, even though Praxair's patent search had not uncovered the references.
  • Relying on essentially the same arguments in the current petition that it raised in its previous IPR. As a result, the PTAB also denied the petition under 35 U.S.C. § 325(d).
(IPR2016-00781, Paper 10 (PTAB Aug. 25, 2016).)
This case involves a petition filed by Praxair to institute an IPR of claims 1-19 of US Patent No. 8,846,112 B2 (the '112 patent) owned by Mallinckrodt Hospital Products IP Ltd. The patent, which issued from a series of continuation and divisional applications, is:
  • Directed to methods of distributing a pharmaceutical product comprising nitric oxide gas.
  • Discloses that nitric oxide is a lung-specific vasodilator that significantly improves blood oxygenation and reduces the need for extracorporeal oxygenation.
In the first IPR, the PTAB issued a final written decision on July 7, 2016 concluding that Praxair had not proven that one of the '112 patent's claims was unpatentable.
In denying institution of a second IPR, the PTAB noted Section 315(e)(1)'s estoppel provision's legislative history that describes grounds that reasonably could have been raised as including prior art a skilled searcher conducting a diligent search reasonably could have been expected to discover. The PTAB concluded that Praxair reasonably could have raised the new references in the first IPR, even though the references were apparently not identified by Praxair until after a US Patent and Trademark Office examiner cited them during prosecution of an application related to the '112 patent.
Praxair argued that it diligently searched for relevant prior art, but the PTAB dismissed Praxair's diligence argument because:
  • It is based on a single search report that:
    • merely lists 15 exemplary search results;
    • does not identify the searcher or its skill or experience;
    • does not explain why the searcher used certain keywords in its search; and
    • does not state whether the references were part of the search results but not selected for the exemplary list.
  • In its petition, Praxair contends that a person of ordinary skill in the art would have sought the references to understand the academic thinking concerning INO therapy.
  • The references are not obscure texts.
  • Other articles by the author of one of the references were cited during the '112 patent's prosecution.
  • One reference was catalogued and accessible at dozens of major libraries in the United States, including the Library of Congress, the National Library of Medicine, and the Harvard University Library.
  • Both references are readily identified by searching Google Books using keywords from the ’112 patent specification.
The PTAB further exercised its discretion under Section 325(d) to deny Praxair's petition on all challenged claims because Praxair:
  • Was advancing the same or substantially the same arguments it presented in the first IPR.
  • Should have been aware of the new references when it filed the first IPR petition.