In a 104-page ruling, U.S. District Judge Mark L. Wolf granted summary judgment in favor of Celltrion and Hospira, finding that a doctrine of equivalents claim made by Janssen Biotech (“Janssen”) with respect to a Remicide®-related patent would ensnare the prior art.

Janssen makes Remicade®, a biologic drug whose active ingredient is the monoclonal antibody infliximab. Id. at 2.  Celltrion and Hospira produce a biosimilar of infliximab sold under the tradenames Inflectra® and Remsima®. Id.  Janssen filed suit in the United States District Court for the District of Massachusetts alleging that Celltrion and Hospira infringe U.S. Patent No. 7,598,083 (“the ’083 patent”) under the doctrine of equivalents through the process used for making the Inflectra® and Remsima® biosimilar products. Id.

Janssen originally alleged that Celltrion and Hospira infringed a patent covering the infliximab antibody; however, the Court invalidated the patent in 2016 for obviousness-type double patenting. Id. (citing Janssen Biotech, Inc. v. Celltrion Healthcare Co., Ltd., 211 F. Supp. 3d 364, 366 (D. Mass. 2016)).  The focus in the case then shifted to the ’083 patent, which “claims a soluble composition [] suitable for producing a final volume of cell culture media and lists 61 ingredients for the media and a concentration range for each.” Id. (internal quotation marks omitted).  The court noted that the ’083 patent does not mention infliximab and that Janssen does not use an embodiment of the claimed invention to produce Remicade®. Id. at 3.  However, Janssen alleged that Celltrion indirectly infringed the ’083 patent by employing a third party to make the cell culture media used to produce its infliximab products and that Hospira was liable for Celltrion’s actions as a joint venturer. Id. at 4.

Celltrion and Hospira “moved for summary judgment of non-infringement on the grounds that Janssen’s asserted scope of equivalents would ensnare the prior art.” Id. at 5.  “The ensnarement defense prevents the patentee from obtaining under the doctrine of equivalents coverage that could not be lawfully obtained from the PTO by literal claims.” Id.  “In other words, the patentee cannot assert a right to a monopoly over equivalents that is so broad that such claims, if included in the patent application, would not have been patentable over prior art.” Id. at 7-8.  When determining whether a doctrine of equivalents theory would ensnare the prior art, the court conducts a “hypothetical claim” analysis, where a hypothetical claim is constructed that literally covers the accused device (i.e., the claimed limitations of the patent are expanded to encompass the features of the accused product). Id. at 8.  The court then determines whether the hypothetical claim is patentable over the prior art. Id.

After conducting a lengthy obviousness analysis, the court found that “no reasonable factfinder could conclude that Janssen [had] satisfied its burden of proving that the hypothetical claims would have been patentable over the [prior art] media,” and held that Celltrion and Hospira were “entitled to summary judgment of non-infringement of the ’083 Patent because Janssen [had] not produced sufficient evidence to prove that the scope of equivalents would not ensnare the prior art.” Id. at 103.

This decision brings an end to a long-running dispute over patents covering and related to infliximab between Celltrion, Hospira, and Janssen.