37 CFR 1.601 Filing of papers in supplemental examination.
- (c) A request for supplemental examination of a patent may be filed at any time during the period of enforceability of the patent.
Under 37 CFR 1.601(c), a patent owner may, at any time during the period of enforceability of a patent, file a request for supplemental examination. This period was set by rule, because the Office believes that Congress could not have intended the Office to expend resources on the supplemental examination of a patent which cannot be enforced. The enforceability period is generally determined by adding six years to the date on which the patent expires, but the period may be extended if litigation is pending. Specifically, if litigation is instituted within the statute of limitations (see 35 U.S.C. 286), requests for supplemental examination may be filed after the statute of limitations has expired, as long as the patent is still enforceable against someone.
It is the responsibility of the patent owner to determine the expiration date of the patent for which supplemental examination is requested. For example, the expiration date of a utility patent may be 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 § 2750et seq.). Any other relevant information should also be taken into account.