ProstaScint (R) Patent Noninfringement Holding Reversed

Goldenberg and Immunomedics, Inc v. Cytogen, Inc. and C.R. Bard, Inc. (Fed. Cir. June 23, 2004)

(GAJARSA) In an appeal of a summary judgment of noninfringement, the Federal Circuit upheld the district court’s claim construction and summary judgment of no literal infringement. However, the appellate panel reversed the lower court’s summary judgment of noninfringement based on the doctrine of equivalents (DOE).

The patent at suit issued in 1984 and involved tumor localization and antigen therapy. (U.S. Patent 4,460,559). Cytogen and Bard’s ProstaScint (R) products (used to image the extent and location of prostate cancer) allegedly infringe this and other patents held by the plaintiffs.


Summary judgment of noninfringement under the doctrine of equivalents is appropriate if “no reasonable jury could determine two elements to be equivalent.”

The district court explained that, under Dey, statements from the ’744 patent could not create prosecution history estoppel for the ’559 patent. For the same reasons stated above, we agree with the district court’s conclusion on this point. Despite the lack of estoppel, however, the district court still found that Immunomedics “had not met the requirements of the ‘function-way-result’ test.”

The district court appears to have viewed the world of antigens as consisting of two distinct categories—those that are intracellular and those that are on the cell surface—and concluded that antigens falling in different halves could not be equivalents as a matter of law. Transmembrane antigens, however, appear to be a category of their own, and are not susceptible to the black and white categorization made by the district court. As a “grey” category, transmembrane antigens are not addressed by the ’559 patent or its prosecution history and might be equivalents to either of the categories identified by the district court if such a finding was made. See generally Warner-Jenkinson, 520 U.S. at 40.Thus, the court remanded for further proceedings.

In dissent, J PROST would have allowed the claim term “intracellular marker substance” to encompass portions of an antigen located inside a cell.