The Federal Circuit recently clarified language in pre-AIA 35 U.S.C. § 102(a) and (e) such that prior work by a subset of inventors of a later application may be available as prior art to that later application. Those provisions establish as prior art matter that was known or used “by others” and published patent applications and issued patents “by another.” Thus, in a straight-forward permutation, knowledge/use/invention by B is prior art to an application by inventor A. Further, it had been widely understood that work by a superset of an inventive entity could be patent-defeating. Stated differently, knowledge/use/invention by A and B jointly is prior art to an application by inventor A (unless A can establish the knowledge/use/invention was in fact A’s alone). In Merck Serono S.A. v. Hopewell Pharma Ventures, Inc., Appeal Nos. 2025-1210, -1211 (Fed. Cir. Oct. 30, 2025), the court clarified that knowledge/use/invention by a subset of inventive entities is also available as prior art. Thus, for example, knowledge/use/invention by A alone is prior art to an application by inventors A and B.
Procedural Background
The case came to the Federal Circuit on appeal of Final Written Decisions in two related Inter Partes Reviews. In both IPRs, Hopewell successfully challenged the patentability of two of Merck’s patents based on an allegedly obvious combination of two references—Bodor (a published PCT application) and Stelmasiak (a journal article). Bodor was filed on March 26, 2004, by Drs. Bodor and Dandiker and published on October 14, 2004. The challenged Merck patents issued from applications that claim the priority benefit of provisional applications filed on December 22, 2004. The challenged Merck patents named four inventors: Drs. De Luca, Ythier, Munafo, and Lopez-Bresnahan. Hopewell asserted Bodor as prior art under pre-AIA 35 U.S.C. § 102(a) or § 102(e).
One of the major disputes during the IPR was the availability of Bodor as prior art. Merck argued that the portion of Bodor cited by Hopewell, which was only a short excerpt, was in fact not the work of Drs. Bodor and Dandiker but instead the work of the four named inventors of the Merck patents. According to Merck, under a partnership agreement between the respective employers of the Bodor inventors and the inventors of Merck’s challenged patents, the latter communicated their invention to the former. Hopewell countered, alleging there was insufficient evidence showing that Dr. De Luca (one of the four inventors of the challenged Merck patents) contributed to the relevant portion of Bodor.
The Patent Trial and Appeal Board (“the Board”) found that, because there is no facial overlap of the inventors of Bodor on the one hand and the challenged Merck patents on the other hand, Hopewell met its initial burden of showing that Bodor qualifies as prior art. Thus, the Board noted that the burden shifted to Merck to come forward with evidence to show that the relevant portion of Bodor, i.e., the portion cited by Hopewell, was not prior art. The Board found that Merck failed to discharge that burden, specifically because it failed to produce evidence showing that Dr. De Luca provided an inventive contribution. In so doing, the Board resolved a legal dispute that had crystallized by holding that work done by Drs. Ythier, Munafo, and Lopez-Bresnahan could be used as prior art against the challenged Merck patents listing those same individuals as inventors and additionally Dr. De Luca.
Federal Circuit Decision
The Federal Circuit affirmed the Board. Among other things, the Federal Circuit held that the Board properly applied pre-AIA 35 U.S.C. § 102(a) and (e) to require absolute identity in the inventive entities to avoid prior art.
The parties devoted much of their briefs to the proper interpretation of various precedent, with Hopewell relying heavily on In re Land, 368 F.2d 866 (C.C.P.A. 1966). In that case, an application filed by two inventors—Land and Rogers—was rejected over a combination of a patent issued to Land individually and a patent issued to Rogers individually. Because there was no indication that any of the relevant portions of the prior patents reflect joint work of Land and Rogers, the court held that the patents to the inventors individually were available as prior art. Merck, on the other hand, relied on its interpretation of other Federal Circuit precedent and certain provisions of the Manual of Patent Examining Procedure (“MPEP”), and also noted numerous instances in which the Patent Office allegedly declined to treat prior work by a subset of inventors as prior art.
The Federal Circuit sided with Hopewell, finding Land applicable and further that “[l]ater opinions of this court have consistently required identity of inventive entity to exclude a reference from the prior art as not ‘by another.’” The court was unmoved by Merck’s insistence that the Board deviated from the MPEP. The court found that Land—and not the MPEP—controls as to the proper legal meaning of “by others” and “by another.”
The Federal Circuit’s clarification of “by others” and “by another” did not end the matter but instead established the proper framework. Thus, the court addressed Merck’s argument that the Board erred in finding that Dr. De Luca did not contribute to the relevant portion of Bodor. Here again, the court sided with Hopewell. In an effort to evidence Dr. De Luca’s alleged contribution, Merck primarily relied on the testimony of Dr. Munafo. However, he testified that he was “not aware of [Dr. De Luca’s] . . . personal intellectual contribution,” and could not “give details” of his alleged contribution, besides the fact that Dr. De Luca’s department was involved in the project.
Conclusion
The Merck case serves as a reminder of the strict identity requirement in order to avoid prior work from serving as prior art under pre-AIA 35 U.S.C. § 102(a) or (e). Thus, patent challengers should not overlook potential prior art simply because there is overlap among the inventive entities. To be sure, the patent owner may be able to remove a reference by showing that the relevant portions of a reference reflect those of the inventive entity of their patent. As the Federal Circuit has previously held, “[w]hat is significant is not merely the differences in the listed inventors, but whether the portions of the reference relied on as prior art, and the subject matter of the claims in question, represent the work of a common inventive entity.” Riverwood Int’l Corp. v. R.A. Jones & Co., Inc., 324 F.3d 1346, 1356 (Fed. Cir. 2003). However, as the Merck case illustrates, patent owners may be unable to muster sufficient evidence in that regard.