The chewing gum patent wars
Within the case
Cadbury’s argument that Abraxis Bioscience, Inc. v. Mayne Pharma Inc., 467 F.3d 1370 (Fed. Cir. 2006), compels a different result is unavailing. The issue in Abraxis was whether diethylenetriaminepentaacetic acid (“DTPA”) could be considered as an equivalent of edetate. Both compounds belonged to “a broad class of structurally analogous compounds known as polyaminocarboxylic acids.” Id. at 1379 n.7. The patentee, however, had narrowly claimed edetate. Id. at 1381. We rejected the
argument that such narrow claiming precluded the pat- entee from arguing that DPTA was an equivalent of edetate. Id. at 1380. In so finding, we relied on the fact that it was unknown at the time of the invention that the properties of DTPA made it a suitable substitute for edetate in the claimed invention. Id. at 1381-82. Because it was unknown that DTPA and edetate were inter- changeable, the patentee had no reason to claim DTPA, and we therefore held that DTPA could be considered to be within the scope of the patent under the doctrine of equivalents. Id.; see also Kinzenbaw v. Deere & Co., 741 F.2d 383, 389 (Fed. Cir. 1984) (“The doctrine of equiva- lents is designed to protect inventors from unscrupulous copyists and unanticipated equivalents.”).
The facts of this case support the opposite inference. The inventors of the ’893 patent were introduced to WS-3 and WS-23 by a salesman for Sterling Organics, the distributor of the compounds, during the same sales call, and they were told that the two compounds were appro- priate for the same uses. Although the fact that WS-23 did not enjoy FEMA-GRAS listing at the time of the invention might have prevented Cadbury from marketing a chewing gum containing a combination of WS-23 and menthol, it would not have precluded the inventors from anticipating that WS-23 could be used as a substitute for WS-3. Thus, the inventors were on notice of the potential interchangeability of WS-23 and WS-3, yet they drafted the claims of the ’893 patent narrowly to recite certain N- substituted-p-menthane carboxamides, not a broader category of carboxamides that would include WS-23. The trial court therefore properly held that Cadbury could not expand the coverage of its patent to include WS-23 through the doctrine of equivalents.
Judge Newman saw things a bit differently:
I concur in Part III of the court’s opinion, and agree that Wrigley does not infringe Cadbury’s ’893 patent. However, I must dissent from Parts I and II. I would sustain the valid- ity of Wrigley’s ’233 patent, for the district court departed from the routine correct law of obviousness and anticipation.
On the correct law, the district court’s decisions on these grounds are not supportable.
She invoked Learned Hand:
The district court erred in holding the ’233 composition prima facie obvious on only part of the evidence, ignoring the evidence that supports unobviousness. As remarked by Judge Learned Hand, “Courts, made up of laymen as they must be, are likely either to underrate, or to overrate, the difficulties in making new and profitable discoveries in fields with which they cannot be familiar; and, so far as it is available, they had best appraise the originality involved by the circumstances which preceded, attended and succeeded the appearance of the invention.” Safety Car Heating & Lighting Co. v. General Elec. Co., 155 F.2d 937, 939 (2d Cir. 1946).
My colleagues’ finding that nexus was not established, maj. op. at 13, is hard to fathom. Cadbury’s own documents showed that Cadbury changed its formulation to copy Wrig- ley’s new gums containing WS-23 and menthol.