In Sanofi-Aventis Deutschland GMBH v. Mylan Pharms, Inc., No. 21-1981 (Fed. Cir. May 9, 2023), the Federal Circuit reversed the PTAB’s finding that Sanofi’s patent claims were obvious, determining the PTAB used the wrong test for deciding whether an existing patent was “analogous” to the one being challenged.

Mylan Pharmaceuticals had asserted all claims of Sanofi’s U.S. Patent No. RE47,614 directed to a drug delivery device were obvious in view of a combination of three references. All challenged claims required a “spring washer” secured by “at least two fixing elements.” Mylan argued that the combination of two references taught use of spring washers within drug-delivery devices. Mylan further argued the third reference disclosed “snap-fit engagement grips” to secure the spring washer, rendering obvious the use of “two fixing elements.”

This third reference, however, was directed not to drug delivery devices, but to clutch bearings used in automobiles. Mylan argued this reference nevertheless addressed an analogous problem, axial fixation and support of two components relative to one another. Sanofi countered that this particular fixation problem was identified in one of the other prior art references, not by the challenged patent. Mylan responded the problems identified in the prior art and those identified in the challenged patent were themselves analogous. 

On appeal, the Federal Circuit stated it had consistently held that the patent challenger must compare the prior art to the challenged patent when considering whether a reference is analogous. Id. at 6 (citing Donner Tech., LLC v. Pro Stage Gear, LLC, 979 F.3d 1353, 1359 (Fed. Cir. 2020)). The court observed that even if one prior art reference addresses a problem analogous to that addressed by the challenged patent, it does not inherently follow that another prior art reference which addresses the problem of the first is thereby deemed art analogous to the challenged patent. This conclusion is reinforced by the purpose of the analogous art test, which is to examine whether a reference can be considered as prior art to the challenged patent in the first place, and an adjudicator must consider the “purposes of both the invention and the prior art,” but the purpose of the “prior art” must be evaluated with reference to the inventor’s purported invention disclosed within the challenged patent. In re Clay, 966 F.2d 656, 658–59 (Fed. Cir. 1992); see also Chemours Co. FC, LLC v. Daikin Indus., Ltd., 4 F.4th 1370, 1376 (Fed. Cir. 2021).

The court determined Mylan did not otherwise, in its Petition, present arguments that that third prior art reference was analogous to the challenged ’614 patent. The court noted that at oral argument Mylan simply made a conclusory statement that this reference and the ’614 patent addressed the “same problem.” The court concluded that Mylan, by arguing only that the third reference was analogous to another prior art reference, and not to the challenged patent, had failed to meet its burden to establish obviousness. The Federal Circuit reversed the PTAB’s finding of non-obviousness. 

In the end, the decision turned on whether Mylan had sufficiently argued that a reference was analogous to the ‘614 patent, and not whether this reference was properly combinable with the other prior art references resulting in the claimed invention. In an IPR proceeding, the patent challenger must be mindful to tie their arguments for each piece of analogous prior art to the challenged patent in some fashion.