The doctrine of equivalents cannot cover an alternative element that appears in the specification but not the claims, the Federal Circuit found on Friday, even in some cases where the patent owner says the alternative is only relevant to other types of embodiments.

In Eagle Pharmaceuticals Inc. v. Slayback Pharma LLC, the claims required (1) the active pharmaceutical ingredient, (2) an antioxidant, and (3) a mixture of polyethylene glycol (PEG) and polypropylene glycol (PG) as a pharmaceutically acceptable fluid. Another “pharmaceutically acceptable fluid” mentioned in the full specification was ethanol, though the claims were silent about ethanol.

Eagle, the patent owner, wanted the claims to also cover ethanol as an equivalent to the PEG/PG mixture. But typically in such situations, the patent owner cannot get coverage of a disclosed-but-unclaimed alternative. Therefore, defendant Slayback argued that their ethanol-based composition does not infringe, even under the doctrine of equivalents.

In response, the patent owner tried to argue that ethanol is only an equivalent in other embodiments. Particularly, they said that the specification only teaches ethanol as an alternative liquid if a chloride salt in place of an antioxidant. For compositions with the antioxidant, they said, the specification does not teach ethanol as an alternative.

The Federal Circuit disagreed, noting that “The disclosure-dedication doctrine does not require the specification to disclose the allegedly dedicated subject matter in an embodiment that exactly matches the claimed embodiment,” citing its own 2002 en banc decision in Johnson & Johnston Assoc. v. R.E. Servs. The court also upheld the decision to enter judgment on the pleadings in a lower court, finding that the patents themselves gave enough information to decide on the equivalents issue without a full trial.

Interestingly, even before any amendments were made, the claims of the earliest-filed Eagle patent asserted here did not recite ethanol as the pharmaceutically acceptable fluid. Even though the patent owner did not narrow the claims during prosecution to exclude ethanol as a fluid, other factors prevented them from covering it as a fluid under the doctrine of equivalents. This case continues a string of recent Federal Circuit cases about the doctrine of equivalents, some of which we have previously discussed here (see our reports on UCB v. Watson and Pharma Tech v. LifeScan).