Prosecution history disclaimer does not apply to the amendment if the examiner is convinced of patentability without regard to the amendment

Trivascular, Inc. v. Samuels, No. 2015-1631 (Fed. Cir. Feb. 5, 2016)

The patentee claimed infringement of its intraluminal stent technology patent, and the alleged infringer filed a petition for inter partes review (IPR) on the grounds that the patent was invalid as obvious. The resolution of this case hinged on the issue of claim construction. The alleged infringer appealed the Patent Trial and Appeal Board’s (PTAB’s or Board’s) decision on several grounds.  

The key issue on appeal was the PTAB’s construction of term “circumferential ridges.” Even though the term was not limited by its terms to “continuously formed” ridges, the PTAB found that the term did not include a series of the stent. The accused infringer appealed the decision on the basis that the broadest reasonable interpretation of the term included “an elevated part of the outer surface” that could be either “continuous or discontinuous.”  

First, the alleged infringer appealed the PTAB’s decision to not use a topological or cartographical definition of the word “ridge” in evaluating the “broadest reasonable interpretation” of the term, which would have resulted in a broader definition and more importantly, in a finding of obviousness. The Federal Circuit reiterated that a general dictionary definition that is consistent with both the specification’s teachings and the remaining claim limitation takes precedence over a topological or cartographical definition. The court stated that the “broadest reasonable interpretation standard does not give the Board an unfettered license to interpret the words in a claim without regard for the full claim language and the written description.”  

The alleged infringer also argued that the PTAB should have applied the doctrine of prosecution history disclaimer to prohibit a construction of “ridges” that is limited to continuous ridges, as opposed to including both continuous and discontinuous ridges. Specifically, the infringer argued that because the patentee responded to the initial rejection by stating that the patent did not disclose “continuous” ridges, and then introduced an amendment adding the word “continuously” to the claim phrase; and because the patentee did not expressly include the term “continuous” in the final issued claims; prosecution history disclaimer should bar the patentee from arguing for a construction that is limited to “continuous” ridges, which was not claimed in the final issued claims.  

The Federal Circuit ruled that the alleged patent infringer failed to meet its burden of demonstrating the existence of a “clear and unmistakable” disclaimer that would have been evident to one skilled in the art. Although the patentee did offer the “continuous” ridges limitation as one of several possible bases for distinguishing the prior art, the examiner never adopted this particular amendment as the reason for allowing the claims over the prior art. Only after a series of subsequent exchanges and interviews showing that the position of the examiner and the patentee changed, did the examiner ultimately allow the claims over the prior art without the proposed amendment. Thus, the examiner was convinced of the patentability of the claimed invention over the prior art by the other amendments made to the relevant claim, without regard to the proposed addition of the word “continuously” to the claims.  

Finally, the alleged patent infringer contended that the PTAB’s conclusion of nonobviousness was inconsistent with its findings from its institution decision because the PTAB ruled that the alleged infringer had initially demonstrated a reasonable expectation of success in demonstrating obviousness. However, the Federal Circuit noted that the PTAB is free to change its view of the merits at the trial stage from its initial findings at the institution stage, after further development of the record.

A copy of the opinion can be found here.