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Enzo IP Suits Against Affy, Roche, Others Move Forward as Court Hands Down Summary Judgment

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A decade-old string of lawsuits that has embroiled seven life sciences firms is closer to resolution following a recent ruling.

Judge Richard Sullivan of the US District Court of the Southern District of New York on Sept. 21 granted in part and denied in part combined and individual motions from Affymetrix, Amersham, Molecular Probes, Orchid Biosciences, PerkinElmer, and Roche Diagnostics for summary judgment, ruling that they do not infringe IP owned by Enzo Biochem and its wholly owned subsidiary Enzo Life Sciences.

Enzo in October 2002 filed suits against the six companies for infringing 15 claims supporting eight of its patents by selling reagent kits, many of which are used in labeling probes on microarrays.

In July 2006, the court settled the interpretations of the eight patents following a Markman hearing. Afterward, the defendants sought summary judgment that they did not infringe the IP in question. While considering the motion, the judge in the case, Judge John Sprizzo, passed away, and the suit was assigned to Sullivan in 2009 (BAN 1/27/2009).

Though the lawsuits involve several patents, the defendants' motion involved only three: US Patent Nos. 4,994,373; 5,328,824; and 5,449,767. The '373 Patent discloses a method for detecting the presence of a certain nucleotide sequence in a sample of DNA by separating it into its two strands and determining whether the unknown sample will bond, or hybridize, with a known nucleotide sequence. The '824 and '767 patents explain how to modify nucleotides and attach detectable labels.

With regard to the '373 patent, attorneys for Affy, Amersham, PerkinElmer, and Roche argued that they did not infringe the ’373 patent because the IP covers only the specific test format in which the probe is labeled and the sample is fixed to a solid support, while the defendants' products use the inverse arrangement, in which the probe is fixed and the sample is labeled.

Enzo's attorneys had argued that even though these companies' labeling kits did not literally infringe its IP, they were still equivalent to the subject claimed in their patent under the so-called doctrine of equivalents. The court however sided with the defendants, noting that Enzo had specifically claimed a format in which the unlabeled sample is attached to a solid support and the labeled probe is unfixed, and therefore its inability to enforce the patent under the doctrine of equivalents was the "cost of its failure to seek protection for this foreseeable alteration of its claimed structure."

As such, the court granted the defendants summary judgment that they did not infringe the '373 patent.

In response to Enzo's claims that the defendants' products infringed the '824 and '767 patents, the six accused companies asserted that their products did not infringe because they relied on directly detectable labels, while Enzo's IP describes only indirectly detectable labels. As Enzo did not argue that the products infringed this limitation under the doctrine of equivalents, the court granted the six firms' request for summary judgment of non-infringement.

However, PerkinElmer asked the court for summary judgment that its products containing acycloterminators, molecules to which fluorescent labels are attached, as well as dideoxynucleotides, similarly did not infringe the '854 patent. Though the parties agreed that PerkinElmer's products did not literally infringe Enzo's IP, the court said it could not conclude that a "reasonable jury" could find that the accused products "infringe under the doctrine of equivalents," and denied PerkinElmer's motion.

Roche arguably had more success, stating that its DIG 5' End Labeling Kits did not infringe the '854 patent literally or under the doctrine of equivalents, an argument that Judge Sullivan agreed with, granting Roche's motion for summary judgment that the kits do not infringe Enzo's IP.

Though Judge Sullivan's decision on the defendants' motions for summary judgment moved the case forward, it has been nearly six years since the motions were made, and it is unclear when the lawsuits will finally be resolved. In his Sept. 21 order, Sullivan requested that the parties submit a joint proposal by Oct. 19 for what the "next steps in this matter should be."