A recent Federal Circuit decision effectively enables defendants in patent infringement suits two parallel chances for challenging validity of asserted patents: in court and in the U.S. Patent and Trademark Office

(?PTO?), which applies a lower evidentiary standard than a court proceeding.

In its September 4, 2008 ruling in In re Swanson, the Federal Circuit affirmed a decision of the Board

of Patent Appeals and Interferences, in which the Board invalidated patent claims in a reexamination

proceeding based on a prior art reference that had been considered in the previous litigation and the

original examination. The ruling clarified the scope of the ?substantial new question of patentability?

requirement used in reexamination proceedings since a 2002 amendment of 35 U.S.C. § 303(a). Specifically, the Federal Circuit held that consideration of a prior art reference in the previous litigation and in the original examination does not preclude a finding of a new question of

patentability based on the same prior art reference in reexamination.

See full legal update for more information.