The Federal Circuit delivered one of its most anticipated opinions in recent years in its Festo decision, concluding that claim elements added during prosecution which narrow the claim are entitled to no range of equivalents.
Question 1:
For the purposes of determining whether an amendment to a claim creates prosecution history estoppel, is "a substantial reason related to patentability" limited to those amendments made to overcome prior art under Section 102 and Section 103, or does "patentability" mean any reason affecting the issuance of a patent?Answer:
A "substantial reason related to patentability" is not limited to overcoming or avoiding prior art, but includes any reason that relates to the statutory requirements of a patent.Question 2:
Does a "voluntary" claim amendment - one not required by the examiner or made in response to a rejection by an examiner for a stated reason - create prosecution history estoppel?Answer:
Yes, "voluntary" claim amendments are treated like any other amendments.Question 3:
If a claim amendment creates prosecution history estoppel, what range of equivalents is available under the doctrine of equivalents for the amended claim element?Answer:
None. When a claim amendment creates prosecution history estoppel with regard to a claim element, application of the doctrine of equivalents to the claim element is completely barred.Question 4:
When "no explanation [for a claim amendment] is established," thus invoking the presumption of prosecution history estoppel under Warner-Jenkinson, what range of equivalents is available under the doctrine of equivalents for the amended claim element?Answer:
When no explanation for a claim amendment is established, no range of equivalents is available for the amended claim element.The Federal Circuit’s en banc answers to four questions provide a concise synopsis of the majority’s reasoning:
The effect of the Federal Circuit’s majority opinion in Festo is draconian - if a patentee cannot establish that a claim amendment was made for some reason unrelated to patentability, he or she is completely barred from alleging infringement under the doctrine of equivalents for that element. The practical meaning of the Federal Circuit’s holding was explored by Judge Plager in a concurring opinion. He surmised that "[a]n unintended consequence . . . may be that patent litigation will lean ever more heavily on the doctrine of equivalents, especially in those cases in which the patent application . . . was approved without any amendment in the area that affects the accused product." Although Festo has been labeled by some as a mortal blow to the doctrine of equivalents, it may actually invigorate the doctrine for narrowly drafted, unamended claims.
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