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Embodiments Missing from CIP Patent Are Not Restricted from Claim Scope

August 12, 2003

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Last Month at the Federal Circuit - September 2003

Judges: Bryson (author), Newman, and Gajarsa

In Cordis Corporation v. Medtronic AVE, Inc., No. 02-1457 (Fed. Cir. Aug. 12, 2003), the Federal Circuit reversed the district court’s judgment of noninfringement after disagreeing with the district court’s claim construction and its application of prosecution history estoppel.

The patents at issue relate to balloonexpandable coronary stents for use in balloonangioplasty procedures. Cordis Corporation (“Cordis”) sued Medtronic AVE, Inc. and several other companies (collectively “Medtronic”) for infringement of U.S. Patent Nos. 4,739,762 (“the ‘762 patent”) and 5,195,984 (“the ‘984 patent”). Each of the asserted claims recites a “wall surface having a substantially uniform thickness and a plurality of slots formed therein.” The district court had construed this limitation to be limited to devices in which the slots are formed by the removal of material. And, because the accused stents have slots that are formed when wire-like material is bent into sinusoidal rings, which are then connected together, the district court granted SJ of no literal infringement. The district court also construed the claim phrase “wall surface having a substantially uniform thickness” to mean the thickness of the wall may not vary by more than 0.001 inch. A jury found the accused stents to infringe under the DOE and awarded Cordis $271 million in damages. On post-trial motions, however, the district court granted JMOL of no infringement, holding that Cordis was barred from asserting equivalence on the foregoing claim limitations.

The Federal Circuit disagreed with the district court’s claim constructions. According to the Federal Circuit, nothing about the phrase “slots formed therein” suggests that the slots must be formed by any particular process. The phrase “slots formed therein” describes the physical characteristics of the product, not the method of its manufacture, according to the Court. The specifications of the ‘762 and ‘984 patents do not define the “slots formed therein” as openings created by the removal of material from a pre-existing wall surface, even though the preferred embodiment discloses such a configuration.

The district court had based its conclusion on the absence of a particular embodiment from a parent application in a CIP application that led to the patents-in-suit. The district court interpreted this omission of an embodiment as a surrendering of bent-wire or wire mesh-like stents. The Federal Circuit rejected this reasoning, concluding that there may have been several reasons that the patentee choose not to include that embodiment in the CIP application. The Court concluded that a patentee may choose not to carry forward a particular embodiment from a parent patent into a CIP application because that embodiment does not satisfy a limitation that was added to the claims in the CIP. That choice, however, does not mean that the scope of the CIP is limited to the preferred embodiments that were carried forward.

Concerning the claim limitation “substantially uniform thickness,” the Federal Circuit concluded that the patent does not set out any numerical standard by which to determine whether the thickness of the wall surface is “substantially uniform.” During the prosecution history, applicants distinguished certain prior art by explaining that the wall thickness of the prior art stent varied at different points and ranged from a minimum thickness of 0.0035 inches to a maximum thickness of 0.0045 inches. According to the Federal Circuit, this prosecution history does not disclaim stents that vary in thickness by 0.001 inches or more. The Federal Circuit ruled that the prosecution history overall did not indicate that this one area of distinction was the only distinguishing feature between the claims and the prior art. Moreover, the Federal Circuit concluded that this particular distinction was not a clear and unmistakable disclaimer.

For the same reasons, this prosecution history did not rise to the clear level necessary to support an argument-based estoppel against application of the DOE. Accordingly, the Federal Circuit reversed the judgments of noninfringement and remanded.