The U.S. Court of Appeals for the Federal Circuit restated the proposition that if a patent applicant wants to initiate an interference with an issued patent, it must present an interfering claim prior to one year of the grant date of the patent.  Adair v. Carter, Case No. 2011-1212 (Fed. Cir. Feb. 7, 2012)(Linn, J.).  This requirement under 35 U.S.C. § 135(b)(1) is known colloquially as the “one-year rule”. 

Section 135(b)(1) requires, in essence, that a claim which is for the same or substantially the same subject matter as a claim to an issued patent may not be made in an application unless such claim is made prior to one year from the date on which the patent was granted.  Notwithstanding the seemingly strict language of § 135(b)(1), there is an exception to this statute. 

As the Court explained, citing to the 1977 Court of Customs and Patent Appeals (CCPA) case of Corbett v. Chisholm, a limited exception to this one-year bar exists “where the copier had already been claiming substantially the same invention as the patentee” during the critical time period.  That is, an applicant can add a claim to his application after the one-year “critical date” and not run afoul of the one-year rule if the added “post-critical date claim” is not materially different from a claim or claims that was filed within the critical period. 

Adair argued that the comparison as to whether its post-critical date claim is materially different should be viewed with respect to the claim in the patent rather than to its pre-critical date claims.  Adair based its argument on U. of California v. U. of Iowa Res. Found. (Fed. Cir. 2006) and In re Berger, 279 F.3d 975 (Fed. Cir. 2002).  The Federal Circuit disagreed, explaining that “the relationship between the post- and pre-critical date claims . . . is not only relevant, but dispositive of the § 135(b)(1) question.” 

The Court further agreed with the Board of Patent Appeals and Interferences (Board) that there were material differences between Adair’s post- and pre-critical date claims.  During prosecution, Adair added several limitations to the post-critical date claim to avoid examiner rejections.  The Court held under Festo (IP Update, Vol. 5, No. 5) that there is a presumption that such amendments are material and therefore the post-critical date claims were presumptively materially different from the pre-critical date claims.  Adair never rebutted this presumption and thus was barred from initiating an interference by the one-year rule.