In this inter partes review proceeding, the challenged patent, filed in July 2011, purported to be a continuation of a parent application filed in September 2009.  Petitioner PRISM argued the challenged claims lacked written description support in the earlier application and therefore were entitled to a priority date no earlier than July 2011.  Consequently, PRISM contended, an intervening reference published in December 2009 anticipated the claims.

Patent Owner Choongwae asserted the challenge was a collateral attack on written-description support issues barred by 35 U.S.C. § 311(b).  Choogwae also asked the Board to deny the Petition under 35 U.S.C. § 325(d) because the same prior art and substantially the same arguments were presented and considered during prosecution of the challenged patent.

The Board did not directly address whether the grounds were barred under § 311(b).  Instead, the Board rejected the Petition under § 325(d) because “the same or substantially the same prior art or arguments previously were presented to the Office.”  Twice during prosecution of the parent application and the challenged patent, Choongwae filed Information Disclosure Statements disclosing unsolicited declarations from PRISM’s co-founder, alleging lack of written description support and anticipation by the intervening reference.  Although the declarations did not specifically enunciate the priority claim challenge, the Board presumed the art unit examiner considered that issue, as the intervening reference identified in the declarations “is prior art only if the claims-at-issue lack written description support in the parent . . . application, and therefore, are not entitled to the priority date” of September 2009.  The Board declined to revisit the examiner’s analysis and denied the petition.

In light of the Board’s decision, it will be an uphill climb for IPR petitioners basing their petitions on prior art addressed during prosecution.  Nevertheless, it appears that collateral attacks on written description support via the priority claim may be permitted.  Thus, when analyzing a patent that claims priority to an earlier application, prospective challengers should consider whether the priority chain can be broken by showing that the priority application does not support one or more claims for which IPR is to be requested, thereby making available intervening patents or publications as prior art. 

Informative OpinionPRISM Pharma Co. v. Choongwae Pharma Corp., IPR2014-00315, Paper 14 (P.T.A.B. July 8, 2014)