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PTAB decision invalidating claims as obvious based on analogous art reversed by Federal Circuit

Procedural History

Sanofi-Aventis Deutschland GMBH v. Mylan Pharmaceuticals Inc. is an appeal from a final written decision in an inter partes proceeding (“IPR”) of the Patent Trial and Appeal Board (“PTAB”) that found claims 1-18 of U.S. Patent No. RE47,614 (“the ’614 Patent”) invalid as obvious over prior art. The Federal Circuit reversed.


Sanofi-Aventis Deutschland GmbH (“Sanofi”) owns the ’614 Patent, which is directed to a drug delivery device that can be configured to allow settings of different dose sizes.  (Slip Op. at 2.) The ’614 Patent uses a spring washer to improve operability with respect to dosage control and improve reproducibility of the dosage in connection with different cartridges. Id. The spring washer exerts force on the cartridge to secure the cartridge against movement and is secured to the housing in a manner that prevents relative axial movement between the spring washer and the housing. (Slip Op. at 2-3.) The ’614 Patent has 18 claims, all of which require a spring washer secured by at least two fixing elements. (Slip Op. at 3.)

Mylan Pharmaceuticals Inc. (“Mylan”) filed a petition for IPR challenging claims 1-18 of the ’614 Patent as obvious based on a combination of three prior art references: (1) U.S. Patent Application No. 2007/0021718 (“Burren”); (2) U.S. Patent No. 2,882,901 (“Venezia”); and (3) U.S. Patent No. 4,144,957 (“de Gennes”). Id. Mylan argued that Burren teaches the use of springs within a drug-delivery device, Burren and Venezia collectively teach the use of spring washers within drug-delivery devices, and de Gennes teaches the addition of “snap-fit engagement grips” to secure the spring washer. (Slip Op. at 3-4.)  Sanofi responded that de Gennes is not analogous art to the ’614 Patent and that a skilled artisan would not have considered a clutch bearing in automobiles to be within the same field as the drug delivery device at issue in the ’614 Patent. (Slip Op. at 4.) Similarly, Sanofi argued that de Gennes is not “reasonably pertinent” to the problem the ’614 Patent addresses (i.e., securing a cartridge against movement within a housing).1 Id.  

The PTAB made two determinations in its final written decision. (Slip Op. at 5.) First, it concluded that Burren and Venezia collectively do not render the challenged claims of the ’614 Patent unpatentable. Id. Second, it held that the three prior art references collectively do render the challenged claims unpatentable because, among other things, de Gennes’s snap-fit connection teaches the fixing elements of the ’614 Patent. Id. The PTAB found that de Gennes constituted analogous art to the ’614 Patent because the reference was “reasonably pertinent” to Mylan’s definition of the problem faced by the inventors of the ’614 Patent: “axially fixing two components relative towards each other.” Id.  

On appeal, Sanofi argued that the PTAB erred by analyzing whether de Gennes constituted analogous art to the ’614 Patent because Mylan only presented arguments with respect to Burren, not de Gennes. (Slip Op. at 6.)  Mylan contended that the PTAB properly evaluated de Gennes as analogous art because Burren’s and the ’614 Patent’s problems are functionally equivalent. (Slip Op. at 6-7.)


First, the Federal Circuit examined the framework a fact-finder must use to evaluate whether a reference constitutes analogous art, explaining that “[t]wo separate tests define the scope of analogous prior art: (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 still is reasonably pertinent to the particular problem with which the inventor is involved.” (Slip Op. at 7.) The Court further elaborated that “[i]n evaluating whether a reference is analogous, we have consistently held that a patent challenger must compare the reference to the challenged patent.” (Slip Op. at 8.)

Applying this framework, the Court reversed the PTAB’s final written decision that de Gennes is analogous art to the ’614 Patent as unsupported by substantial evidence. (Slip Op. at 7-13.) While the Court noted that Mylan, as petitioner, was “not required to anticipate and raise analogous art arguments in its petition,” it observed that Mylan argued that de Gennes was analogous to Burren, but not to the ’614 Patent, in its reply. (Slip Op. at 12-13.) Therefore, the Court held that Mylan had not met its burden to establish obviousness premised on de Gennes and thus the PTAB’s factual finding on this issue was erroneous. (Slip Op. at 13.)

Key Takeaway

Patent challengers in an IPR proceeding should tether analogous prior art arguments to the challenged patent, not merely to other prior art. 


1 The PTAB rejected Sanofi’s definition of the ’614 Patent’s problem as too narrow. (Slip Op. at 5.)