Specific Exclusion Exception to the Doctrine of Equivalence

MucosalLayerCook Biotech v. ACell (Fed. Cir. 2006).

Cook’s claims were directed to a urinary bladder submucosa derived tissue graft composition that is entirely delaminated from “the luminal portion of the tunica mucosa.”  The graft can be implanted to support damaged tissues.  A number of claim construction and inventorship issues were raised.  However, an interesting aspect of the case is the court’s further development of the specific exclusion exception to the doctrine of equivalents.

The specific exclusion exception can be considered part of the “all limitations rule” and operates to exclude from the doctrine of equivalents, any elements “specifically excluded by a claim limitation.”

A claim that specifically excludes an element cannot through a theory of equivalence be used to capture a composition that contains that expressly excluded element without violating the “all limitations rule.”

Here, the accused infringing product contains at least a portion of the luminal portion of the tunica mucosa.  ACell argued, and the CAFC agreed, that the DOE cannot be extended to the accused product without rendering the delamination requirement meaningless.

Permitting appellees to assert such a theory of equivalence would effectively remove the requirement that the urinary bladder submucosa be delaminated from “the luminal portion of the tunica mucosa.”

Although the CAFC does not use the term “vitiation” here, the specific exclusion exception is essentially the same concept. As the court held in the 2005 Freedman Seating case,

an element of an accused product or process is not, as a matter of law, equivalent to a limitation of the claimed invention if such a finding would entirely vitiate the limitation.