2211 Time for Requesting Ex Parte Reexamination under 35 U.S.C. 302 [R-07.2015]
Under 37 CFR 1.510(a), any person may, at any time during the period of enforceability of a patent, file a request for ex parte reexamination. This period was set by rule, since the Office considered that Congress could not have intended expending Office resources on deciding patent validity questions in patents which cannot be enforced. See Patlex Corp. v. Mossinghoff, 758 F.2d 594, 225 USPQ 243, 249 (Fed. Cir. 1985). The period of enforceability is generally determined by adding 6 years to the date on which the patent expires but the period may be extended if there is pending litigation. Specifically, if litigation is instituted within the period of the statute of limitations, requests for reexamination may be filed after the statute of limitations has expired, as long as the patent is still enforceable.
The patent expiration date for a utility patent, for example, is determined by taking into account the term of the patent, whether maintenance fees have been paid for the patent, whether any disclaimer was filed as to the patent to shorten its term, any patent term extensions or adjustments for delays within the Office under 35 U.S.C. 154 (see MPEP § 2710, et seq.), and any patent term extensions available under 35 U.S.C. 156 for premarket regulatory review (see MPEP § 2750 et. seq.). Any other relevant information should also be taken into account.