Recent decisions of the Patent Trial and Appeal Board (PTAB) confirm that in an inter partes review (IPR) the “broadest reasonable interpretation” (BRI) does not apply to expired patents.  Rather, expired patent claims undergoing an IPR should be construed in accordance with the methodology used by a district court. 

The rule has long been that while claims are generally given their broadest possible scope during prosecution, claims of an expired patent undergoing reexamination are construed in a manner similar to that of a district court's review.  In re Rambus, Inc., 694 F.3d 42, 46 (Fed. Cir. 2012).

Two recent IPR decisions raise this issue.  In Toyota Motor Corp. v. Leroy G. Hagenbuch, Case IPR2013-00483, Paper 19, April 15, 2014, the Board asked the parties to brief the issue of the appropriate standard for interpreting claims after they have been terminally disclaimed.  No decision is yet available but our expectation is that the BRI standard will not apply.

In Amkor Technology, Inc. v. Tessera, Inc., Case IPR2013-00242, Paper 117, April 14, 2014, the Board and the parties agreed that after a patent has expired the BRI should not be applied but rather the claims should be construed in a fashion similar to that used in a district court’s review. 

Indeed, the regulations specifically state that BRI applies to “unexpired patents,” which implies that BRI does not apply to expired patents.  See 37 C.F.R. 100(b), 200(b), and 300(b) (“A claim in an unexpired patent shall be given its broadest reasonable construction in light of the specification of the patent in which it appears.”)

The rationale for not following the BRI approach in interpreting expired claims takes into account the fact that the reexamination law (35 U.S.C. §305) permits patent owners to amend their claims to avoid cited prior art.   However, if a patent undergoing reexamination has expired, the patent owner's right to amend its claims is terminated.  See 37 CFR § 1.530(d).  Ex Parte Papst–Motoren, 1 U.S.P.Q.2d 1655, 1655–56 (B.P.A.I. Dec. 23, 1986).

The Papst-Motoren board concluded that in reexamination proceedings in which the Patent and Trademark Office is considering the patentability of claims of an expired patent which are not subject to amendment, a policy of liberal claim construction may properly and should be applied.  Such a policy favors a construction of a patent claim that will render it valid, i.e., a narrow construction, over a broad construction that would render it invalid.  Id., citing ACS Hosp. Systems, Inc. v. Montefiore Hosp., 732 F.2d 1572 [221 USPQ 929] (Fed. Cir. 1984) and Carmen Indus., Inc. v. Wahl, 724 F.2d 932 [220 USPQ 481] (Fed. Cir. 1983).

While the PTAB does not discuss this rationale in either Toyota or Amkor, one is only left to assume that it has adopted this rationale for claim construction in an IPR.