When responding to an office action from the Patent and Trademark Office (PTO), a representative must carefully consider not only the potential impact of amending claims, but also the possible longer-term ramifications of her arguments. By doing so, the practitioner can avoid unnecessarily limiting the protective scope of her claims. While most representatives are aware of the effects that prosecution history estoppel or disclaimer can have on a patent during litigation, practitioners should also consider how their remarks might be interpreted during a reexamination. Additionally, as implementation of post-grant procedures begins, practitioners should monitor developments of the procedures as they pertain to remarks, amendments, claim construction and equivalents.

Response language

When drafting a response, it is important to ensure that it characterizes only the prior art, not the claims. By not characterizing the claims, the practitioner can reduce the likelihood that prosecution history estoppel or disclaimer will be attached. It is important to be mindful of how a possible infringer might attempt to construe the words in the response as a characterization of claim language, rather than comment on the art of record. If amendments are made for reasons not related to prior art, the related remarks should make that fact abundantly clear. It is generally best to avoid blanket assertions that amendments are not necessitated by prior art. Instead a representative should present an appropriately detailed explanation of the reasons for the amendment. She should review her remarks concerning claim amendments, both objectively and subjectively, in order to discover and eliminate those comments, which an opponent might persuasively characterize as raising estoppel or disclaimer issues.


While many practitioners are mindful that remarks and amendments made during prosecution can be cited during litigation, practitioners must also understand the possible effect that prosecution history can have on subsequent requests for reexamination and on possible constructions of art by the PTO. When deciding whether to grant a request, the office will review the file history including statements the patent owner made through its representatives. For example, an examiner might cite a reference, but fail to apply the reference against the claims. It may thus be wise for the representative to submit remarks concerning the art, so as to create an obstacle for a third-party requester who might otherwise describe the art as a “non-applied reference.”  In doing so, a practitioner can effectively raise the threshold for a substantial new question of patentability.

Post-grant procedures

Practitioners should pay close attention to the post-grant procedures in the new rules so that they can take the procedures into account when responding to the PTO during prosecution. The new rules will provide potential infringers with additional avenues to challenge validity outside of court, and practitioners must be aware of the implications that these procedures have for prosecution.  


When a practitioner prepares a response to an

action, the practitioner should consider how amendments and remarks might be interpreted during future litigation, reexamination or other post-grant procedures. By being careful, the practitioner can avoid unnecessarily limiting the scope of protection afforded by the resulting patent.