The US Court of Appeals for the Federal Circuit affirmed the vacatur of a jury verdict of infringement under the doctrine of equivalents and denial of infringement judgment as a matter of law (JMOL) where the patentee failed to propose a proper hypothetical claim in a post-trial proceeding on whether (1) the doctrine of equivalents theory ensnared the prior art and (2) substantial evidence supported the jury verdict of no literal infringement. Jang v. Boston Scientific Corp., Case Nos. 16-1275; -1575 (Fed. Cir., Sept. 29, 2017) (Chen, J).

G. David Jang, MD, is the named inventor of a patent directed to coronary stents. The claimed stents include “expansion columns” made up of sinusoidal expansion struts and “connecting strut columns” made up of connecting struts that have end sections that connect to expansion struts in different expansion columns, and an intermediate section that is not parallel to the two end sections. The connecting struts connect the expansion struts in a “peak-to-peak” configuration.

As part of an agreement between Jang and Boston Scientific Corporation (BSC), BSC was obligated to pay Jang a royalty on stents that practiced Jang’s patent. Jang and BSC disputed whether the BSC Express stent gave rise to a royalty obligation. The Express stent has two types of alternating columns or elements, referred to as “macroelements” and “microelements.” Both elements are sinusoidal, and linear bars join the microelements and macroelements together in a “peak-to-valley” configuration.

At trial, the jury returned a verdict of infringement under the doctrine of equivalents, and the district court conducted a post-trial proceeding on ensnarement. Jang elected to use a hypothetical claim analysis to establish his entitlement to the scope of equivalents, and asserted two different hypothetical claims. After concluding that neither proposed hypothetical claim was proper, the district court vacated the jury verdict of infringement under the doctrine of equivalents and entered judgment of non-infringement in favor of BSC. Jang then moved for JMOL of literal infringement, which the district court denied because substantial evidence supported the jury’s finding of no literal infringement.

Jang appealed the vacatur, arguing that his proposed hypothetical claims were proper, but that if they were flawed, the district court should have devised its own hypothetical claim to proceed with the ensnarement analysis. The Federal Circuit disagreed on both points. Specifically, the Court found that Jang’s first proposed hypothetical claim improperly narrowed the actual claim in some respects, and that his second proposed hypothetical claim improperly failed to broaden the actual claim. Accordingly, the Federal Circuit found that the district court properly rejected Jang’s proposals. Moreover, the Court explained that the patentee has the burden of establishing the patentability of the hypothetical claim, and therefore the district court was under no obligation to propose a hypothetical claim. Because Jang failed to establish the patentability of any hypothetical claim, the Federal Circuit affirmed vacatur of the jury’s verdict of infringement under the doctrine of equivalents.

Jang also appealed the denial of JMOL of literal infringement. The Federal Circuit, noting expert testimony that the microelements and macroelements of the Express stent were both more like the claimed expansion columns than the claimed connecting strut columns, and that the Express stent used a “peak-to-valley” configuration as opposed to the claimed “peak-to-peak” configuration, found that substantial evidence supported the jury’s verdict of no literal infringement. Accordingly, the Court affirmed the district court’s denial of JMOL.

Practice Note: The propriety of hypothetical claims is a threshold question in an ensnarement analysis. It is the patent owner’s burden to present a proposed hypothetical claim (or claims) that is both broader than the underlying actual claim and patentable over the prior art.