United States Court of Appeals for the Federal Circuit ______________________

SANOFI-AVENTIS DEUTSCHLAND GMBH, Appellant

v.

MYLAN PHARMACEUTICALS INC., Appellee ______________________

2021-1981 ______________________

Appeal from the United States Patent and Trademark Office, Patent Trial and Appeal Board in No. IPR2019- 01657. ______________________

Decided: May 9, 2023 ______________________

KENNETH WAYNE DARBY, Fish & Richardson PC, Aus- tin, TX, argued for appellant. Also represented by MATT COLVIN, Dallas, TX; LAUREN ANN DEGNAN, WALTER KARL RENNER, Washington, DC; JOHN STEPHEN GOETZ, New York, NY.

DOUGLAS H. CARSTEN, McDermott Will & Emery, Ir- vine, CA, argued for appellee. Also represented by WENDY L. DEVINE, Wilson, Sonsini, Goodrich & Rosati, PC, San Francisco, CA; ELHAM FIROUZI STEINER, San Diego, CA; TASHA THOMAS, RICHARD TORCZON, Washington, DC. ______________________ Case: 21-1981 Document: 36 Page: 2 Filed: 05/09/2023

2 SANOFI-AVENTIS DEUTSCHLAND GMBH v. MYLAN PHARMACEUTICALS INC.

Before REYNA, MAYER, and CUNNINGHAM, Circuit Judges. CUNNINGHAM, Circuit Judge. Sanofi-Aventis Deutschland GmbH owns U.S. Patent No. RE47,614 (“the ’614 patent”). Mylan Pharmaceuticals Inc. petitioned the Patent Trial and Appeal Board (“Board”) for inter partes review of claims 1–18 of the ’614 patent. In its final written decision, the Board found all challenged claims unpatentable as obvious over prior art. Mylan Pharms. Inc. v. Sanofi-Aventis Deutschland GmbH, IPR2019-01657, Paper 39, 2021 WL 1158193 (P.T.A.B. Mar. 26, 2021) (“Decision”). Sanofi argues on appeal that Mylan failed to argue that U.S. Patent No. 4,144,957 (“de Gennes”) constitutes analogous art to the ’614 patent and instead compared de Gennes to another prior art reference. We agree with Sanofi. Because Mylan argued that de Gennes is analogous to another prior art reference and not the challenged patent, Mylan did not meet its burden to establish obviousness premised on de Gennes and the Board’s factual findings regarding analogousness are not supported by substantial evidence. We reverse. I. BACKGROUND A. The Challenged Patents The ’614 patent is entitled “Drug Delivery Device and Method of Manufacturing a Drug Delivery Device.” The ’614 patent’s stated invention relates to a “drug delivery device” that can be “configured to allow setting of different dose sizes.” ’614 patent col. 1 ll. 26–32. The ’614 patent seeks to provide a drug delivery device to improve “operability with respect to dosage control and/or improved reproducibility of the dosage in connection with different cartridges.” Id. col. 1 ll. 51–55. It purport- edly 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 Case: 21-1981 Document: 36 Page: 3 Filed: 05/09/2023

SANOFI-AVENTIS DEUTSCHLAND GMBH v. 3 MYLAN PHARMACEUTICALS INC.

washer and housing.” Id. col. 1 ll. 59–67, col. 2 ll. 31–35. The ’614 patent explains that spring washers are advanta- geous because spring washers can secure the cartridge “without requiring much space,” allowing for “a very com- pact drug delivery device.” Id. col. 2 ll. 15–17. The ’614 patent has 18 claims, all of which require a “spring washer” secured by “at least two fixing elements.” Id. col. 8 l. 1 to col. 10 l. 18. As an example, claim 1 recites: 1. A drug delivery device comprising: a housing with a proximal end and a distal end,