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IP Alert
IP Alert: Pitfalls of Pivoting During Patent Prosecution

September 15, 2016

The recent Federal Circuit case UCB, Inc., v. Yeda Research and Development Co., Ltd. provides a vivid example of the complexity of patent prosecution and the difficult strategic choices that applicants sometimes must make. In Yeda Research, patentee Yeda lost its case because the U.S. Patent and Trademark Office (USPTO) rejected an attempted amendment during prosecution of the patent at issue. Had Yeda not attempted this amendment, it likely would have obtained a patent with exactly the same claim language, and very well might have won its case. At the very least, Yeda would not have lost on the grounds enumerated by the district court.

Developing a concept into a market-viable product may require “pivoting” along the way—that is, changing course to implement a new product strategy. What happens when it is decided to pivot to an embodiment not previously considered, and thus not disclosed in the patent application? Patent claims are not necessarily limited to the embodiments disclosed in the patent. By way of example, a patent claim that specifies a “support beam” likely would be held to cover a stainless steel support beam, even if the patent specification described a support beam made of ordinary steel. For this reason, the courts and the USPTO must determine whether the claims are specifically written to only the disclosed embodiments or whether the claims more broadly encompass other embodiments not disclosed. When the competitor’s product includes a stainless steel support beam, it is tempting to add a claim that recites stainless steel support beams. Doing so removes the risk that the USPTO or the courts may decide that the claims do not encompass stainless steel support beams, and provides a potential fallback position in case the broader claim is held invalid over the prior art. If, however, only ordinary steel support beams are disclosed in the patent, then it may be counterproductive to attempt to add such a claim—the effort may backfire.

That is what happened to Yeda in this case. The patent in Yeda Research was drawn to “antibodies,” an invention in the biological sciences. At the time the patent was drafted, the specification described only antibodies that were derived from mice (known as “murine-derived” antibodies). Subsequently, though, Yeda sought to pivot, attempting to present broader claims that did not specify the animal source of the antibodies. In addition, Yeda presented claims specifically drawn to antibodies derived from other animals, including rat and hamster, as well as a claim drawn generally to non-mouse-derived antibodies (“non-murine”).

The USPTO rejected the broad claim not specifying the source of the antibodies for lack of enablement. In response, Yeda submitted an expert declaration that stated that any gaps between the disclosed murine-derived antibodies and the claim breadth could be easily bridged by those skilled in the art at the time the application was filed. Upon receipt of this declaration, the USPTO conceded Yeda’s position and allowed the broad claim. As this broad claim did not specify the animal source, it presumably would have extended patent protection to non-murine antibodies, including antibodies derived from rat and hamster.

But the USPTO rejected the specific claims to rat, hamster, and non-murine antibodies for lack of written description. The USPTO determined that the specification did not say “non-murine” and did not expressly specify rat or hamster, even though the specification broadly enabled this claim scope. Yeda responded by canceling these claims, and the USPTO then allowed the application.

Yeda then sued UCB for infringing the resulting patent. UCB’s Cimzia® product line included non-murine antibodies. At the district court, UCB moved for summary judgment of noninfringement. According to UCB, Yeda had given up non-murine antibodies to obtain a patent. Agreeing that Yeda had surrendered non-murine antibodies, the court granted UCB’s motion, and Yeda appealed.

On appeal, the Federal Circuit affirmed, holding that the claims could not be construed to cover non-murine antibodies despite the broad, enabling disclosure. The court reasoned that “a patent applicant cannot later obtain scope that was requested during prosecution, rejected by the [USPTO], and then withdrawn by the applicant.” In other words, because Yeda had requested claims specifically reciting non-murine antibodies, was denied this claim, and then canceled this claim, Yeda would not be permitted to assert the patent against non-murine antibodies.

The court rejected Yeda’s argument that the claim should be construed as broadly as the enabling scope of the specification permitted. Specifically, the court held, “Yeda is correct in that generic terms in claims are construed in light of that which is already known. However, the content of the specification and actions and arguments during prosecution must also be considered, in defining the scope of a generic term in a claim.” Based upon Yeda cancelling the claims specifically reciting “non-murine” antibodies so it could receive a patent, the court found that prosecution history estoppel precluded Yeda from asserting the claim not specifying the source of the antibodies against UCB’s Cimzia non-murine product line. The court further rejected Yeda’s argument that no prosecution history estoppel should apply because claim 1 had not been amended during prosecution, reasoning that Yeda had withdrawn claims that were specifically drawn to the non-murine embodiments and therefore could not construe its generic patent claim to cover such embodiments.

This result is striking. Yeda successfully obtained a claim broadly covering antibodies regardless of their source, which the USPTO expressly found enabled by the specification. Despite this, Yeda was held to be estopped from asserting the full scope of the claim based on its failed effort to claim rat, hamster, and non-murine antibodies.

What if Yeda had not attempted to present the claims specifically reciting “non-murine” antibodies? Had Yeda not done so, then the court might not have construed the broadly worded genus claim to exclude the antibodies UCB’s Cimzia product line. In any case, absent the failed attempt to specifically claim non-murine antibodies, the court would have had no grounds for its holding of prosecution history estoppel. Although Yeda cannot necessarily be faulted for its effort, had Yeda successfully been able to obtain the “non-murine” claim, it seems certain that the court would have construed the claim the other way, and Yeda would have had a potential fallback claim.

It may seem odd that claims presumably providing patent protection to non-murine antibodies—including antibodies derived from rat and hamster—were allowed, while claims specifically reciting rat, hamster, and non-murine antibodies were rejected. But this result follows from the patent laws. The description of general features and characteristics of a claimed feature does not necessarily describe a particular embodiment of that feature—e.g., “steel” does not necessarily describe “stainless steel,” as noted above. Consequently, Yeda’s attempt to amend the claims to recite the source of the antibody was held to impermissibly attempt to specify more than described. A patent applicant presented with a similar opportunity to amend claims has a difficult decision to make, as the Yeda Research decision illustrates.

If you have questions regarding this case, please contact Fitch Even partner Allen E. Hoover or attorney James A. Zak, author of this alert.


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