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2000 Term, Number 17 / June 18, 2001

Today the Supreme Court granted certiorari in one case of potential interest to the business community. Amicus briefs in support of the petitioners are due on Thursday, August 2, 2001, and amicus briefs in support of the respondents are due on Tuesday, September 4, 2001. Any questions about this case should be directed to Eileen Penner (202-263-3242) or Miriam Nemetz (202-263-3253) in our Washington office.

Patent Law --- Doctrine of Equivalents --- Prosecution History Estoppel. The doctrine of equivalents provides patent protection against allegedly infringing devices that — although not falling literally within the claims of a patent — involve only unimportant and insubstantial changes to a patented invention. Prosecution history estoppel operates as a check on the doctrine of equivalents by providing that no range of equivalents is available as to aspects of the invention that have been surrendered by the inventor in the form of limiting amendments to claims during the patent prosecution process. The Court granted certiorari in Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., No. 00-1543, to decide several important questions regarding the balance between the doctrine of equivalents and prosecution history estoppel.

Festo Corporation owns two patents directed to linear actuators used in a variety of industrial applications. The patent examiner initially rejected Festo's claims under 35 U.S.C. § 112, ¶ 1, which requires that the patent specification contain a clear and concise description of the best mode of carrying out the invention. The examiner also objected to the claims under 35 U.S.C. §112, ¶ 2, which requires that the patent particularly point out and distinctly define the invention. After Festo amended certain claims, the Patent and Trademark Office issued the patents.

Festo sued Shoketsu Kinzoku Kogyo Kabushiki Co. ("SMC") for infringement of its patents. SMC's accused device was different in minor ways from the terms of Festo's patents, which precluded a finding of literal infringement. SMC was nevertheless found to have infringed under the doctrine of equivalents. The Federal Circuit affirmed. 72 F.3d 857 (1995).

SMC petitioned for certiorari, and the Supreme Court vacated the Federal Circuit's decision, see 520 U.S. 1111 (1997), and remanded the case for reconsideration in light of Warner-Jenkinson Co. v. Hilton-Davis Chemical Co., 520 U.S. 17 (1997). In Warner-Jenkinson, the Court reaffirmed the vitality of the doctrine of equivalents, but imposed a structured, element-by-element analysis requiring the factfinder to determine whether an accused device or process contains an equivalent of each element of the asserted patent claim, rather than merely considering whether the device as a whole is substantially similar. The Court also held that prosecution history estoppel applies only when the limits imposed by the amendment relate to the patentability of the invention. Id. at 30-32. The Court placed the burden on the patent holder to demonstrate the reason for an amendment during the prosecution process, and established a rebuttable presumption that all amendments are "related to patentability." Id. at 33.

On remand, a panel of the Federal Circuit affirmed the finding of infringement as to one of Festo's patents and remanded to the district court to determine the reason for amendments to the other patent. 172 F.3d 1361 (1999). The Federal Circuit then reheard the case en banc, presenting five "en banc questions" for briefing and argument. 187 F.3d 1381 (1999).

The en banc Federal Circuit reversed outright, reaching only the first four questions it had posed. 234 F.3d 558 (2000). First, by an 11-1 margin, the court of appeals held that "a narrowing amendment made for any reason related to the statutory requirements for a patent will give rise to prosecution history estoppel with respect to the amended claim element." Id. at 566. The court refused to limit prosecution history estoppel to amendments made to overcome prior art (i.e., amendments made to differentiate the invention from the body of knowledge in the field at the time the patent is sought).

Second, the court determined that "voluntary" claim amendments — amendments neither required by the patent examiner nor made in response to a rejection by the examiner — should be "treated the same as other amendments." 234 F.3d at 568. Accordingly, "a voluntary amendment that narrows the scope of a claim for a reason related to the statutory requirements for a patent will give rise to prosecution history estoppel as to the amended claim element." Ibid.

The court divided most closely in resolving the third question, which addressed the range of equivalents available for claim amendments that had given rise to prosecution history estoppel. By an 8-4 vote, the court held "that prosecution history estoppel acts as a complete bar to the application of the doctrine of equivalents when an amendment has narrowed the scope of a claim for a reason related to patentability." 234 F.3d at 574. To reach this result, the court overruled most of its prior decisions on the point. See id. at 574-575. Those decisions had applied a "flexible bar" approach, under which the range of equivalents was determined by examining the factors necessitating the claim amendment, and the doctrine of equivalents may apply to the amended claim if the accused device differs from the literal terms of the patent only as to an aspect of the amended claim that did not form the basis of the amendment. The en banc court found the "flexible bar" analysis "‘unworkable'" because it imposed too much uncertainty on the scope of equivalents surrendered by a claim amendment; by contrast, the court believed that the "complete bar" approach better serves the notice and definitional function of patent claims. Id. at 575-578.

Finally, the court held that, "[w]hen no explanation for a claim amendment is established, no range of equivalents is available for the claim element so amended." 234 F.3d at 578. Based on its resolution of the en banc questions, the court reversed the judgment against SMC because Festo's claim amendments estopped it from asserting the doctrine of equivalents. See id. at 591.

Judges Michel, Rader, Linn, and Newman each wrote dissenting opinions. Judge Newman was the only dissenter as to the first question, but all four judges dissented from the en banc court's adoption of the "complete bar" rule. The dissenting judges believed that the "complete bar" was inconsistent with Warner-Jenkinson and earlier Supreme Court decisions. See, e.g., 234 F.3d at 631-634 (dissenting opinion of Newman, J.). The dissenters also considered the "complete bar" rule unsound as a matter of policy. In their view, the "complete bar" would provide copyists with a relatively safe method of avoiding liability for infringement by making an insubstantial change to a claim element that had been amended during the prosecution process (see, e.g., id. at 616-617 (dissenting opinion of Michel, J.)). A "complete bar" also would provide inventors with insufficient protection against equivalent technology arising after issuance of the patent. See, e.g., id. at 619-620 (dissenting opinion of Rader, J.).

This case is of exceptional significance to intellectual property owners — particularly those seeking to enforce patents with amended claims — and to all businesses operating in heavily patented technological fields. The scope and availability of the doctrine of equivalents may be acutely important in the context of patents for biotechnology, computer software and circuitry, and business methods. Patentees concerned with protecting their rights against near-exact copies, and innovators threatened by the assertion of indeterminate patent rights, have equal interests in presenting their perspectives to the Court, especially if their experiences shed practical light on the analytical issues to be decided.

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The Court invited the Solicitor General to express the views of the United States in the following case of interest to the business community:

Chevron U.S.A., Inc. v. Echazabal, No. 00-1406: The question presented is whether a person who is unable to carry out the essential functions of a job without incurring significant risks to his own health and safety is a "qualified individual with a disability" entitled to the protections of the Americans with Disabilities Act. Decision below: 226 F.3d 1063 (9th Cir. 2000). Mayer, Brown & Platt is counsel of record for Chevron.

This Mayer, Brown, Rowe & Maw Supreme Court Docket Report provides information and comments on legal issues and developments of interest to our clients and friends. The foregoing is not a comprehensive treatment of the subject matter covered and is not intended to provide legal advice. Readers should seek specific legal advice before taking any action with respect to the matters discussed herein.

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