Federal Circuit IP

Sanofi-Aventis Deutschland GMBH v. Mylan Pharmaceuticals Inc.

By Julia F. Kottmeier Published June 20, 2023

Overview: For determining analogous art, the problem addressed by the cited reference must be compared to that of the patent at issue (not only to problems addressed in other prior art references).


  • Mylan filed IPR against Sanofi’s U.S. Pat. No. RE47,614 (“the ’614 Patent”), which is directed to a drug delivery device including a spring washer for fixing a position of a cartridge within the device and providing higher accuracy drug delivery.
  • Mylan argued the ‘614 Patent was obvious in view of a combination of three references, including U.S. Pat. Pub. No. 2007/0021718 (“Burren”) directed to a syringe, U.S. Pat. No. 4,144,957 (“de Gennes”) directed to a clutch bearing, and a third reference directed to a syringe including a spring washer. Mylan asserted de Gennes addressed a problem analogous to Burren (“axially fixing two components relative to each other”).
  • The Board found all challenged claims unpatentable for obviousness based on the combined references, finding that de Gennes was “reasonably pertinent” to a problem faced in the ’614 Patent (“axially fixing two components relative to each other”).
  • Sanofi appealed on grounds that Mylan failed to argue that de Gennes was analogous to the ’614 Patent, and therefore the Board’s decision lacks substantial evidence.

Issue: Whether Mylan met its burden to establish obviousness of the ’614 Patent premised on de Gennes.

Test for Analogous 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 same field, whether the reference is reasonably pertinent to the particular problem with which the inventor is involved.

CAFC Decision and Analysis: Reversed the Board’s decision.

Did Mylan meet its burden to establish obviousness of the ’614 Patent based on de Gennes? – NO

  • Rationale: In evaluating whether a reference is analogous, a patent challenger must compare the reference to the challenged patent. The purpose of the analogous art test is to examine whether a reference can be considered prior art to the challenged patent.  Although the challenger can look to problems solved in the prior art and can construe the scope of analogous art broadly (KSR), the problems addressed by the challenged patent cannot be ignored or excluded.  In its Petition and Response, Mylan argued that de Gennes addressed a problem analogous to that addressed in Burren (“axially fixing two components relative to each other”) but failed to compare de Gennes to the challenged patent.  At Oral Arguments, Mylan further asserted that Burren and ’614 Patent address the same problem – “accommodating cartridges of various lengths,” but never connected de Gennes or the problem of de Gennes to the ’614 Patent.  Instead, Mylan disputed the need to frame its arguments as to the ’614 patent and accused Sanofi of misinterpreting the law.
  • Holding: Mylan had a burden to assert that de Gennes is analogous to the ’614 patent to show obviousness of the ‘614 Patent, and it did not meet that burden. Therefore, the Board lacked substantial evidence to support its finding of obviousness premised on de Gennes.


  • Ensure that in an analogous art argument, the problem of the cited art is compared to that of a patent challenged in an IPR or to that of a patent application under prosecution.
  • The Board cannot fill in gaps in a petitioner’s arguments – may be a basis for appeal of a PTAB decision.
  • Even if it is believed that the opposing party misinterprets the law, provide the alternative argument regardless (arguendo)!