• Finally Festo - U.S. Supreme Court Issues Long-Awaited Ruling
  • May 6, 2003
  • Law Firm: Orrick, Herrington & Sutcliffe LLP - San Francisco Office
  • The U.S. Supreme Court issued its long-awaited opinion in Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd on May 28, 2002. Generally, the Supreme Court considered the effect of patent claim amendment on the application of the doctrine of equivalents for purposes of a finding of patent infringement. The Supreme Court reviewed an en banc Federal Circuit decision that held: (1) prosecution history estoppel applied to every narrowing claim amendment made to satisfy patentability requirements; and (2) prosecution history estoppel barred reliance on the doctrine of equivalents where narrowing amendments were made to a claim limitation for reasons of patentability.

    With respect to the first issue, the Supreme Court agreed with the Federal Circuit that "a narrowing amendment made to satisfy any requirement of the Patent Act may give rise to an estoppel." Slip Op. at 11. However, on the more important issue of the effect of such an amendment, the Supreme Court rejected the Federal Circuit's absolute bar approach, and instead concluded that "[t]hough prosecution history estoppel can bar challenges to a wide range of equivalents, its reach requires an examination of the subject matter surrendered by the narrowing amendment." Slip Op. at 12.

    The Supreme Court stated that prosecution history estoppel prevents a patentee from recapturing through the doctrine of equivalents the subject matter that was specifically surrendered in order to obtain the patent. Rejecting the Federal Circuit's approach, the Supreme Court held that such estoppel need not be a complete bar to asserting infringement against all equivalents to the narrowed element. Rather, the Supreme Court placed the burden on the patentee to explain that the amendment was not made for reasons of patentability. If unable to meet that burden, the patentee could not rely on the doctrine of equivalents as to that claim element "for all subject matter between the broader and the narrower language." Further, the Supreme Court placed the burden on the patentee to demonstrate "that the amendment does not surrender the particular equivalent in question." Slip Op. at 15. The patentee can do so by showing that "at the time of the amendment one skilled in the art could not reasonably be expected to have drafted a claim that would have literally encompassed the alleged equivalent." Id.

    The Supreme Court's decision in Festo raises a number of issues for those seeking to enforce patents, and those defending against claims of patent infringement. The Supreme Court has shifted the infringement analysis from the Federal Circuit's "bright line" approach to a case-by-case inquiry. Both those asserting and defending against claims based on the doctrine of equivalents must now carefully scrutinize claim amendments to determine their effects. The proper presentation of the record surrounding such amendments may become critical to litigation outcomes. In addition, patent prosecutors should now consider whether appeal, rather than acquiescence and amendment may still be a safer prosecution strategy, at least for high value patent applications. Finally, those relying on opinions of counsel should review those opinions in light of the Supreme Court's Festo decision.