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Patent Specification's Disclaimer of Invention's Scope May Break Chain of Priority

By Payal Majumdar, Ph.D. & Peter Schechter

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In Akeva, LLC, v. Nike, Inc.,[1] the U.S. Court of Appeals for the Federal Circuit (“CAFC”) held that a disclaimer of claim scope in a patent specification that excluded a particular embodiment prevented later claims in the continuation patents from claiming the excluded embodiment, thereby breaking the priority chain.  The Court also held that a disclaimer of claim scope in a specification could not be subsequently rescinded without introducing prohibited new matter.   As a result, summary judgment of both non-infringement and invalidity was affirmed.

Akeva owned a portfolio of footwear patents describing improvements to athletic shoe rear soles and midsoles (“the Asserted Patents”).  A subset of four of the five Asserted Patents claimed priority to the fifth (“the ’126 Patent”), that subset being referred to as “the Continuation Patents.”   

Asics filed for declaratory judgment that it does not infringe the Asserted Patents and, in response, Akeva countersued for patent infringement. Akeva also added Nike, Inc., adidas America, Inc., New Balance Athletic Shoe, Inc., and Puma North America, Inc. to the suit alleging infringement of certain claims of the Asserted Patents. The district court granted Nike’s summary judgment of invalidity of the Continuation Patents because they were not entitled to claim priority to the ’126 patent.  On appeal, the CAFC held that the district court correctly determined that the Continuation Patents were not eligible to claim priority to the ’126 patent. 

The specification of the ’126 Patent describes the problem of rear sole wear in a shoe having a conventional fixed rear sole, in which “the heel typically wears out much faster than the rest of the athletic shoe, thus requiring replacement of the entire shoe even though the bulk of the shoe is still in satisfactory condition.” The ’126 Patent thus discloses a solution to the problem with a conventional fixed rear sole by replacing it with either a detachable rear sole that can be replaced or a rear sole that is rotatable.

All of Nike’s accused shoes included a conventional fixed rear sole, and Nike contended that the term “rear sole secured” in claim 25 of the ’126 Patent could not encompass a shoe with a conventional fixed rear sole because such claim scope was specifically disclaimed in the specification of an intervening patent in the priority chain that was not one of the Asserted Patents.  More specifically, the priority chain of all of the Continuation Patents included the unasserted ’300 Patent, a continuation-in-part of the ’126 Patent.  In previous litigation, the CAFC held that the ’300 Patent’s specification disclaimed conventional fixed rear soles, thus preventing the claims of the ’300 Patent from encompassing shoes with a conventional fixed rear sole.  

Akeva had subsequently deleted the specification disclaimer in the applications that issued as the Continuation Patents.  The trial court determined that Akeva’s revisions to the specifications of the Continuation Patents introduced new matter by broadening the disclosure, and as result the Continuation Patents could not claim priority through the ’300 Patent back to the ’126 Patent. The district court therefore held that the Continuation Patents were invalid under the on-sale bar of 35 U.S.C. Section 102. 

Akeva appealed, and the CAFC affirmed. Given the disparagement of conventional fixed rear sole shoes which suffer from rear sole wear found in both the ’126 Patent and ’300 Patent, their characterization of the invention as a removable and/or rotatable rear sole, and their uniform, lengthy disclosure of such rear soles, the CAFC agreed with the district court’s construction of “rear sole secured” to mean “rear sole selectively or permanently fastened, but not permanently fixed into position” disclaimed conventional rear fixed soles. The Court noted that several statements in the specification made it evident a conventional fixed rear sole was not within the scope of the invention. Accordingly, after reviewing the specification, the CAFC agreed with the district court that both the ’126 Patent and ’300 Patent disclaimed shoes with conventional fixed rear soles.

The CAFC then considered the district court’s ruling that the Continuation Patents could not claim priority to the ’126 Patent. The Court observed that to be entitled to the ’126 Patent priority date,

“there must be adequate written description support for the Continuation Patent claims through the chain of applications leading back to the ’126 patent, which here includes the ’300 patent. The disclaimer in the ’300 patent specifically excluded an athletic shoe with the conventional fixed rear sole and midsole insert from the patent’s scope, breaking any continuity of disclosure for that embodiment. As a result, the Continuation Patents cannot reach through the ’300 patent to claim an earlier priority date for claims directed to a shoe having a conventional fixed rear sole.

The CAFC explained that the “fundamental problem” with Akeva’s priority argument was that the ’300 patent disclaimed and failed to describe shoes with conventional fixed rear soles. Due to break in the priority chain, the asserted claims of the Continuation Patents could not claim priority to the ’126 patent for a shoe having a conventional fixed rear sole.
Akeva argued that the prior disclaimers were rescinded in the Continuation Patents, enabling the Continuation Patents to claim priority to the ’126 patent. The CAFC disagreed and held that a specification disclaimer to a specific embodiment could not be rescinded without introducing new matter. The Court explained that rescinding the specification disclaimer would bring an entirely new embodiment into the Continuation Patents that had originally been excluded from the ’300 patent’s disclosure. Such an embodiment would be “classical new matter” and is not within the scope of the invention as disclosed in the prior patent. Therefore, the CAFC agreed with the district court that the ’300 patent severed the priority chain for the Continuation Patents’ claims. Consequently, the CAFC held that the asserted claims of the Continuation Patents were anticipated.

There are several lessons to be learned from this case.  First, patent application specifications must be drafted carefully to seek broader scope of protection for the invention by including or describing any and all technical alternatives/embodiments to the invention. Second, a disclaimer of scope of the invention in any application in a priority chain prevents subsequent applications in the chain from recapturing the disclaimed claim scope without simultaneously breaking the priority chain.  Third, the decision highlights some of the limits patentees face when attempting to change strategies or fix errors made during prosecution as a result of a narrowly drafted specification. 


[1] 817 Fed. Appx. 1005 (Fed. Cir. 2020).