Reexamination of Expired Patents

Takeaways

• Expired patents may be eligible for reexamination.
• Owner’s options during reexamination of an expired patent are severely limited.

Similar to reexamination practice, which has long allowed reexamination of expired patents through the end of patent enforceability, the Federal Circuit has precedentially held that PTAB post-grant proceedings could be granted and conducted upon expired patents. However, reexamination of expired patents has been available since the creation of the proceeding.

Established in 1981 by PL 96-517, ex parte reexamination is the Office’s oldest experiment with administrative patent revocation proceedings. When created, 37 C.F.R. § 1.510(a) provided that “any person may, at any time during the period of enforceability of a patent, file a request for ex parte reexamination.” This period of “patent enforceability” was set by rule, since the Office considered that Congress could not have intended expending Office resources on deciding patent validity questions in patents that cannot be enforced. The court soon confirmed the Office made the correct choice. Patlex Corp. v. Mossinghoff, 758 F.2d 594 (Fed. Cir. 1985).

It must be appreciated that patent enforceability is different than patent expiration. Generally, enforceability is six years from the date of patent expiration, and may be extended even longer if patent litigation has been instituted and remains pending. Patent expiration is determined by taking into account the term of the patent, whether maintenance fees have been paid, whether any disclaimer was filed shortening the patent term, any patent term extensions or adjustments for delays within the Office under 35 U.S.C. § 154, and any patent term extensions available under 35 U.S.C. § 156 for premarket regulatory review. Thus, requesters may request reexaminations on expired yet still enforceable patents and owners may be called to defend their claims before the CRU if such a reexamination is granted, albeit under a changed claim construction standard and without the ability to amend.

Practically, there are advantages and disadvantages to reexaminations during this post-expiration point of a patent’s enforceable life, depending on which side one views the issue. A determination to reexamine may be made at any time during the period of enforceability of a patent. Thus, requests for reexamination, including the rare reexamination ordered at the Director’s initiative, may be undertaken well into the enforceability period. After patent expiration, no claim amendments may be proposed by owner. No amendment other than the cancellation of claims will be incorporated into the patent by a reexamination certificate issued after the expiration of the patent. Moreover, the Office must apply the Phillips standard (ordinary and customary meaning” during claim construction and reexamination rather than the more liberal “broadest reasonable interpretation” standard used in the reexamination of unexpired patents. See Phillips v. AWH Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005), In re Rambus, Inc., 694 F.3d. 42 (Fed. Cir. 2012), and In re Yamamoto, 740 F.2d 1569 (Fed. Cir. 1984).

During the expired-but-enforceable period of a patent, reexamination provides a viable administrative patent revocation proceeding that has a deeply developed body of case law. Such guidance can provide a requester with greater certainty than pursuing administrative revocation through PTAB post-grant proceedings where the body of case law still remains under development even after 12 years.