Does an Ex Parte Requester Have Two Bites at the Apple?

Scott Daniels | July 1, 2010

A requester in an inter partes reexamination is estopped from arguing in subsequent litigation an invalidity issue that it “raised or could have raised” in the reexamination.  35 U.S. § 315(c).  There is no corresponding estoppel provision against ex parte requesters.  Nevertheless, reexamination practitioners often assert that there is a de facto estoppel against an ex parte requester who later reasserts in litigation the reexamination references.

That may not be true in all courts.  Earlier this week, Magistrate Judge Mark Falk granted a motion to stay pending resolution of a reexamination in Wabco Holdings v. Bendix, 2010 U.S. Dist. LEXIS 64036 (D.N.J.).  The patentee did not oppose the stay, but requested that the accused infringer “be unable to challenge the validity of any claims that survive the USPTO’s reexamination based on the prior art that the USPTO considers.”

Magistrate Falk refused to impose such a condition.  He explained at some length that it was the intent of Congress that ex parte reexamination requesters have “two bites of the apple.”

Congress made a distinction between ex parte reexaminations and inter partes reexaminations … Congress estops the third-party from asserting, in a later civil action, the invalidity of any of the claims that the USPTO deems valid in the inter partes reexamination.

Because an ex parte requester is not allowed to participate in the reexamination, Congress does not estop it from challenging the validity in future litigation.

If Congress thought that a third-party requester in an ex parte reexamination would receive two bites of the apple by being allowed to assert invalidity arguments in a later patent infringement suit, then it could have estopped the party in the same way that it does in inter partes reexaminations.  Congress chose not to.

A de facto estoppel against ex parte requesters may exist in some courts, but not in Magistrate Falk’s.

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