Recent decisions by the Federal Circuit have affirmed findings of inequitable conduct based on a failure of the applicant to cite material references that were in the applicant’s possession and not cumulative of other previously-cited references.  The result of the inequitable conduct findings were that the patents-in-suit were rendered unenforceable.  In some instances, the material reference was cited (or created) by the United States Patent and Trademark Office (USPTO), during prosecution of another applications also owned by the patentee and copending with the application that issued as the patent-in-suit.  Additionally, the “other” application was not always a family member (related through common priority) of the application that issued as the patent-in suit.  References created by the USPTO, such as Office Actions (which may include positions opposite to those the applicant is currently taking) and Notices of Allowance (which may pertain to double-patenting issues), have also been considered sufficiently material and noncumulative to support a finding of inequitable conduct.  See McKesson Information Solutions, Inc. v. Bridge Medical, Inc., 47 F3d 897, 82 USPQ2d 1865, Fed Cir. 2007

To mitigate the risk of one of its patents being rendered unenforceable for failing to cite a material reference, businesses (especially those with large patent portfolios) may want to consider establishing procedures to determine whether a reference cited during prosecution in one application should be cited in another application, i.e., whether the reference is material to the claim in another application and noncumulative of previously-cited references.  One manner of doing this is to actively track pending applications and group them based on claimed subject matter.  The grouping should not necessarily be restricted to family members  and should include both U.S. and foreign applications.  When a references (including Office Actions and Notices of Allowance) is cited in one case within a group, consideration can be given to whether that reference should be cited in other cases in that group.  The applicant should also consider how a material reference is being characterized, since taking inconsistent positions with respect to material references whether made during U.S. or foreign prosecution has been used to support a finding of inequitable conduct.  See Therasense, Inc. v. Becton, Dickinson & Co., 593 F3d 1289, 93 USPQ2d 1489, Fed. Cir. 2010