Reverse Doctrine of Equivalents as an Escape From Literal Infringement? Unlikely, but worth a shot.

In Steuben Foods, Inc., v. Shibuya Hoppmann Corporation et al., 202301790, Decided January 24, 2025, the Federal Circuit revisited the reverse doctrine of equivalents (RDOE).

In patent law, the Doctrine of Equivalents (DOE) allows for a finding of infringement, even if a product or process does not literally infringe a patent claim, if the accused product or process contains elements identical or equivalent to each claimed element of the patent claim.

Under the RDOE, a literal infringer may avoid liability if “the accused ‘product has been so far changed in principle [from the asserted claims] that it performs the same or similar function in a substantially different way.'”

But is the RDOE even a viable defense? Maybe. In its decision, the Federal Circuit, although noting: (1) that “RDOE [is] an ‘anochronistic exception, long mentioned but rarely applied'”; (2) that it has never affirmed a decision finding noninfringement based on the reverse doctrine of equivalents; and (3) that Steuben’s arguments that the RDOE did not survive the 1952 Patent Act were compelling, declined to decide whether RDOE was a viable defense. Instead, the Federal Circuit reversed the JMOL, finding that there was substantial evidence to rebut any prima facie case of RDOE. 

Moving Forward

So what should alleged infringers do? RDOE has not been declared an invalid defense to literal infringement, even though it seems that may occur one day. Thus, for now, one should evaluate each situation to decide whether an assertion of RDOE may be proper.

The full decision is available here: Steuben Foods, Inc. v. Shibuya et al.

If you need assistance in filing a patent application, please contact the author of this post, Fabian Nehrbass, Patent Attorney, or one of our other registered Patent Attorneys.