The “Inventive Step” in Analogous Prior Art
The “Inventive Step” in Analogous Prior Art

In Sanofi-Aventis Deutschland GMBH v. Mylan Pharmaceuticals Inc., No. 2021-1981, 2023 U.S. App. LEXIS 11311 (Fed. Cir. 2023), the Federal Circuit reversed a decision by the Patent Trial and Appeal Board (“PTAB”) that found all challenged claims of U.S. Patent No. RE47,614 (“the ‘614 patent”) unpatentable in Inter Partes Review (IPR) IPR2019-01657. The Petitioner (Mylan) argued that the combination of three prior art references rendered the claims obvious. In attempting to sustain its burden of establishing obviousness, Mylan appears to have attempted to apply the European Patent Office (“EPO”) standard and argued that one of the prior art references was analogous to another prior art reference but not to the ‘614 patent itself.

Summary of Facts
The ‘614 patent’s stated invention relates to a “drug delivery device” that can be configured to allow setting of different dose sizes”Id, at *2  (internal citations omitted). It achieves this objective using a spring washer that can “exert a force on the cartridge and secure the cartridge against movement” and is “secured to the housing so as to prevent relative axial movement between [the] spring washer and housing.” Id. at *2-3 (internal citations omitted). The claims all require a “‘spring washer’ secured by ‘at least two fixing elements.’” Id. at *3 (internal citations omitted).

Mylan’s petition asserted that all claims were obvious based on a combination of three prior art references, Buren, Venezia, and de Gennes. Mylan sought to combine Burren with Venezia to teach the use of “spring washers” within a drug-delivery system and used de Gennes to add “snap-fit engagement grips” to secure the washer. Mylan argued that de Gennes constituted analogous art because it addressed a problem pertinent to that addressed in Burren. However, Mylan failed to make any argument that de Gennes was pertinent to the problem addressed in the ‘614 patent.

Sanofi responded by arguing that de Gennes relates to cars and not medical devices such that a person of ordinary skill in the art would not consider it to be in the same field of endeavor as the ‘614 patent, nor is de Gennes reasonably pertinent to the problem presented in the ‘614 patent. Id. at *4. However, the PTAB ruled in favor of Mylan, reasoning that Sanofi’s definition of the problem was too narrow.

Analogous Art Arguments/Test
On appeal, Sanofi argued that the PTAB “altered and extended” Mylan’s argument by analyzing whether de Gennes was analogous art to the ‘614 patent when Mylan only presented arguments with respect to Burren. Id. at *6 (internal citations omitted). Sanofi further argued that the PTAB “adopted Mylan’s problem statement derived from Burren and then worked backward to relate that problem to the ‘614 patent.” In response, Mylan argued that the PTAB was correct in treating de Gennes as analogous art because there is no functional difference between the problem presented in Burren and the problem presented in the ‘614 patent.

The Federal Circuit agreed with Sanofi that Mylan failed to carry its burden in establishing de Gennes as analogous art to the ‘614 patent. In its reasoning, the Court examined the framework a fact finder must use when evaluating whether a reference is analogous art by applying two separate tests as set forth in In re Bigio:

(1) whether the art is from the same field of endeavor, regardless of the problem addressed, and

(2) if the reference is not within the field of the inventor’s endeavor, whether the reference is still reasonably pertinent to the particular problem with which the inventor is involved.

Id. at *7 (citing In re Bigio, 381 F.3d 1320, 1325 (Fed. Cir. 2004)). The Federal Circuit has also consistently held that when evaluating whether a reference is analogous art a patent challenger must compare the reference to the challenged patent. Id. at 10 (Donner Tech., 979 F.3d 1353, 1359 (Fed. Cir. 2020)). Accepting Mylan’s arguments would allow a challenger to focus on the problems of alleged prior art references while ignoring the problems of the patent that is being challenged. “Even if a reference is analogous to one problem considered in another reference, it does not follow that the reference would be analogous to the problems of the challenged patent.” Id. at *12.

Finally, the Court analyzed whether, in light of the above framework, Mylan properly supported its argument that de Gennes is analogous art to the ‘614 patent. Here, Mylan failed to carry its burden of establishing de Gennes as analogous art because its argument was framed with respect to Burren rather than the ‘614 patent. Because the PTAB found that Burren and Venezia alone do not render the claims of the ‘614 patent obvious without considering de Gennes, the Federal Circuit held that Mylan failed to meet its burden of establishing obviousness and reversed the PTAB’s decision

Contrast to EPO Practice
In many instances, the standards for establishing non-obviousness under 35 U.S.C. §103 closely parallel their EPO counterpart for the “inventive step” of EPC Art. 56. However, Sanofi-Aventis, highlights a divergence between the USPTO and EPO.

Under the EPO’s “problem solution” approach, “the technical problem means the aim and task of modifying or adapting the closest prior art to provide the technical effects that the invention provides over the closest prior art.” (5.2 Formulation of the objective technical problem ( To formulate the technical problem, the “Guidelines for Examination in the European Patent Office”, (the EPO counterpart to the MPEP) instructs that “one studies the application (or the patent), the closest prior art and the difference (also called “the distinguishing feature(s)” of the claimed invention) in terms of features (either structural or functional) between the claimed invention and the closest prior art, identifies the technical effect resulting from the distinguishing features, and then formulates the technical problem.” Id. The EPO expressly states that “[t]he objective technical problem derived in this way may not be what the applicant presented as “the problem” in the application.” Id. As a result, under the EPO approach, “the formulated problem should be one which the skilled person would wish to solve knowing only the prior art”.” (EPO - T 0800/91 (Heat-shrinkable film/KUREHA) of 20.7.1995

In Sanofi-Aventis, Mylan effectively tried to apply the EPO approach in its IPR proceeding by establishing de Gennes in the context of the problem identified in Burren rather than the ‘614 patent. However, the Court expressly rejected this approach. Instead, the Court held that under 35 U.S.C. §103, the inquiry is based on the problem identified by the patent, not based on solving the gap between the closet prior art and the claimed invention.

For Patent Owners in an IPR
Patent Owners facing a challenge based on potentially non-analogous art need to be mindful that it is the petitioner’s burden to show that all references are analogous art to the patent being challenged. Accordingly, Patent Owners, particularly at the Patent Owner Preliminary Response (“POPR”) stage, can benefit from framing the problem solved by the challenged patent in a manner that is different than the problem addressed by the cited references. If the PTAB adopts the Patent Owners’ framing of the problem as different than the cited art, the IPR petition will be denied because the cited references are not analogous art. 

For Petitioners in an IPR
A petitioner bears the burden of showing that the cited reference is analogous to the challenged patent and not other prior art references. As a result, Petitioners relying upon art that has the potential of being categorized as non-analogous need to carefully craft the problem addressed by the challenged patent in a way that includes the art.



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