To what extent are statements made during prosecution, which alter the meaning of a claim, enough to invoke the doctrine of prosecution history disclaimer? The Federal Circuit, in Ecolab, Inc. v. FMC Corporation, recently took a step in answering this question.

Prosecution history disclaimer occurs when an Applicant, or agent of the Applicant, makes disclaiming statements with reference to claim language during the prosecution of a patent application. The Federal Circuit found that in this case, a single statement made during prosecution was not enough to invoke prosecution history disclaimer.

Ecolab appealed and FMC cross-appealed from the district court’s final judgment based on three issues. The first issue concerned the jury’s verdict that Ecolab infringed certain claims of FMC’s U.S. Patent No. 5,632,676 (“the ‘676 patent”).

The second issue concerned FMC’s willful infringement of certain claims of Ecolab’s U.S. Patent Nos. 6,010,729 (“the ‘729 patent”) and 6,113,963 (“the ‘963 patent”). The third issue concerned the invalidity of certain claims of the Ecolab patents.

The patents at issue are directed to the use of peracetic acid (“PAA”), an antimicrobial agent, as a sanitizer in beef and poultry processing.

Ecolab asserted that the district court should have granted judgment as a matter of law (“JMOL”) that Ecolab did not infringe the ‘676 patent claims, and that FMC induced infringement of Ecolab’s patent claims.

On the other hand, FMC asserted that the district court should have: i) granted JMOL that certain claims of the ‘729 patent and the ‘963 patent are invalid as anticipated or obvious in light of the prior art, ii) Ecolab induced infringement of FMC’s patent claims, and iii) FMC did not willfully infringe Ecolab’s patent claims.

The Federal Circuit affirmed the district court’s denial of Ecolab’s motion for JMOL of noninfringement of the ‘676 patent claims based on the following. During prosecution, FMC made statements indicating that PAA is the sole antimicrobial agent in the sanitizing solution, to distinguish over prior art cited by the patent examiner. Ecolab asserted that these statements made by FMC altered the meaning of the claim language, “consisting essentially of [PAA],” to exclude compositions that contain multiple antimicrobial agents, including Ecolab’s composition.

The Federal Circuit held that FMC’s statements, when considered in the context of the prosecution history as a whole, are not clear and unmistakable enough to invoke the doctrine of prosecution history disclaimer.

The examiner had responded to FMC’s statements that PAA is the sole antimicrobial agent in the sanitizing solution by noting that the claim language, “consisting essentially of [PAA],” does not limit the claims to compositions containing PAA as the sole antimicrobial agent.

Following the examiner’s clarification, FMC did not repeat the allegedly disclaiming statements, but instead, set forth alternative arguments for patentability. Because these statements, when considering the prosecution as a whole, tend to negate FMC’s earlier statement, the Federal Circuit declined to find that FMC had limited the claim by disclaimer.

In this case, Ecolab also asserted that its product cannot infringe the ‘676 patent claims because the ‘676 patent explicitly states that the claim term, “sanitize,” “denote[s] a bacterial population reduction to a level that is safe for human handling and consumption,” yet its product does not and cannot make raw poultry safe for human consumption because cooking is required. The Federal Circuit held that, while an inventor may act as his own lexicographer (defining claim terms in the specification regardless of common or technical meaning) and that courts must construe claims as written, the definition of “sanitize” is ambiguous in that it does not indicate when consumption is to take place. Based on expert testimony, the Federal Circuit determined that consumption occurs after cooking.

The Federal Circuit reversed the district court’s denial of FMC’s motion for JMOL that certain claims of the ‘729 patent and the ‘963 patent are invalid as anticipated or obvious.

With respect to anticipation, the Federal Circuit found that the jury’s verdict was not supported by substantial evidence and pointed to FMC’s expert testimony, addressing each element of the ‘729 patent claim, showing how each element was disclosed in a prior art publication. As a result, the Federal Circuit further dismissed Ecolab’s arguments of undue experimentation based upon the extensive testing required to develop the Ecolab product.

With respect to obviousness, the Federal Circuit held that the addition of an “at least 50 psi” pressure limitation in the ‘963 patent claims would have been obvious because the advantages of spraying antimicrobial solutions onto meat at high pressure were known, and thus there was an apparent reason to combine the known elements in the fashion claimed. Additionally, a person of ordinary skill would have known how to make this combination. Accordingly, the Federal Circuit held that the claims are invalid as obvious because the claims recite a combination of familiar elements to yield predictable results.