Everything you say in the patent application can come back to bite you. WILSON v. MARTIN

A patent is a set of exclusive rights granted to the inventor of a new invention. The steps that an inventor follows to gain a patent is referred to as patent prosecution. Patent prosecution is a cooperative, interactive process in which the patent applicant and the applicant’s attorney work with the staff and the United States Patent and Trademark Office to address various concerns regarding an invention’s patentability.

The patent prosecution process typically begins with an inventor choosing a patent attorney to assist them. The patent attorney will review the invention to determine the likelihood a patent can be obtained. The patent attorney then files a patent application with the United States Patent and Trademark Office. The United States Patent and Trademark Office will assign an examining attorney to review the patent application. The applicant’s attorney and the examining attorney will communicate regularly during the patent examination process until the patent is granted or the examining attorney refuses to issue a patent.

The patent examination process and the communication that the patent applicant has with the patent examiner must be carefully crafted. This is because all communications are preserved after the patent is granted. What a patent applicant makes a statement during the examination of the patent application, it cannot later make an inconsistent statement. Judicial estoppel prevents a patent applicant from making one argument during prosecution and an opposite argument afterwards.

The doctrine of judicial estoppel provides that where a party successfully urges a particular position in a legal proceeding, it is estopped from taking a contrary position in a subsequent proceeding where its interests have changed. To decide whether to apply judicial estoppel, courts typically consider several factors, including (1) whether a party’s later position is “clearly inconsistent” with its earlier position; (2) whether a court has accepted the party’s prior position, such that accepting its “inconsistent position in a later proceeding would create the perception that either the first or the second court was misled”; and (3) whether the party changing its position “would derive an unfair advantage or impose an unfair detriment on the opposing party if not estopped.”

WILSON v. MARTIN, 2018-1980 (C.A.F.C. 2019) is a case which illustrates the pitfalls that can be created by judicial estoppel. Wilson filed an interference proceeding against Martin to invalidate certain claims of U.S Patent No. 8,809,044 unpatentable as anticipated or obvious. The patent relates to growing animal cells in a device that has a membrane that is gas permeable but not liquid permeable. The interference proceeding went to the Patent Trial and Appeal Board, who sided with Martin.

The case revolved around one piece of prior art, U.S. Patent No. 6,759,245 (“Toner”), which relates to growing animal cells in a device. The patent examiner raised it as an objection during patent examination, Martin explained how the prior art didn’t apply. Wilson claims that Martin’s explanation of how the ‘245 was not prior art to the Patent Trial and Appeal Board was opposite the argument made during patent examination.

Wilson appealed to the Court of Appeals for the Federal Circuit on the grounds that Martin’s argument was barred by judicial estoppel. The Federal Circuit sided with Martin. The Federal Circuit noted that Toner’s Figure 8b was referenced by Martin in the patent examination process, in the interference proceeding Toner’s Figure 8a was referenced. The statements made during the patent examination process and the interference proceeding were related to different aspects of the prior art and therefore the Board did not err in finding judicial estoppel did not apply.

While Martin prevailed in this case, the important takeaway is a patent applicant must carefully craft all responses to a patent examiner because those responses are attached to the patent forever.

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