Prosecution History Estoppel in Patent Litigation: Avoiding the Presumption, Limitation of Doctrine of Equivalents

Recording of a 90-minute premium CLE video webinar with Q&A

Conducted on Thursday, May 27, 2021

Recorded event now available

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Course Materials

This CLE course will guide patent litigators on prosecution history estoppel and when it applies. The panel will discuss the exceptions and the guidance provided by the courts in recent decisions. The panel will review strategies to avoid the presumption of estoppel while getting the desired claim allowed.


Prosecution history estoppel can play an important role in patent litigation. Patent litigators must understand the scope of the estoppel as well as when it applies. The Supreme Court held that under the doctrine of equivalents, an accused product or process that does not literally include every limitation of an asserted patent claim can still infringe the claim if it includes an equivalent of the missing limitation. Warner-Jenkinson Co. v. Hilton Davis Chem Co. (1997).

The presumption of estoppel arises when a claim is amended to overcome a rejection. Once there is a presumption of estoppel it is difficult to overcome. For estoppel to be triggered, the claim amendment must have been made for the claim to be patentable and must narrow the claim. It is important to know when an amendment is considered to be narrowing.

The case law is complicated and not always clear. Counsel must understand how the courts have treated prosecution history estoppel and when the courts have allowed some claims.

Listen as our authoritative panel of patent attorneys examines prosecution history estoppel. The panel will discuss the exceptions when they apply and the courts' guidance in recent decisions. The panel will review strategies to avoid the presumption of estoppel while getting the desired claim allowed.



  1. Prosecution history estoppel
    1. When it applies
    2. Limiting the use of equivalents to expand protection
  2. Exceptions
  3. Recent court treatment
  4. Best practices for avoiding or overcoming the presumption


The panel will review these and other important issues:

  • What are the criteria for rebuttal of the presumption of estoppel?
  • How have the courts addressed the application of prosecution history estoppel?
  • What options are available to avoid the presumption of prosecution history estoppel?


Hughey, Rachel
Rachel C. Hughey

Merchant & Gould

As a Co-Chair of the firm’s Appellate Practice, Ms. Hughey is one of the firm’s appellate specialists. She...  |  Read More

Jakes, J. Michael
J. Michael Jakes

Finnegan Henderson Farabow Garrett & Dunner

Mr. Jakes concentrates his practice on patent litigation and related counseling. He serves as lead counsel in federal...  |  Read More

Noonan, Kevin
Kevin E. Noonan, Ph.D.

McDonnell Boehnen Hulbert & Berghoff

Dr. Noonan's practice involves all aspects of patent prosecution, interferences, and litigation. He represents...  |  Read More

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