Attacking Patents On Written Description & Enablement Grounds In Inter Partes Review

Although Inter Partes Review (IPR) is limited to grounds of unpatentability based upon prior art references, it is nevertheless possible to raise issues of written description or enablement by applying intervening prior art that is published between two priority dates for a claimed invention. Such intervening prior art may even be applied between two filing dates created by a continuation application, even though no new material has been introduced into the application with the later filing date. In re NTP, 654 F.3d 1279 (Fed. Cir. 2011). The Board has specifically held that entitlement to priority is appropriately determined in the context of an IPR. See IPR2013-00323, paper no. 62, citing In re NTP.

Recent Cases

This approach has now been applied in several further IPRs with mixed results. For example, the petitioners relied on intervening prior art in IPR2014-00315 and IPR2015-00291. While the Board did not institute IPR in the former petition, it did institute IPR in the latter. One reason appears to be that the petition in IPR2015-00291 included a new expert declaration specifically addressing the factors required to evaluate written description and enablement of the specification of the patent at issue, constituting new evidence not previously considered in original prosecution. By contrast, in IPR2014-00315, the petition used arguments that had already been considered in the original prosecution of the patent at issue.

This intervening art tactic may be particularly useful in the life sciences area, as illustrated by IPR2015-00291. There have been recent decisions by the Federal Circuit in relation to written description and lack of...