Last week, in Enzo Biochem Inc. v. Applera Corp., the Federal Circuit determined that the District Court for the District of Connecticut accurately interpreted the Federal Circuit's decision in Enzo Biochem, Inc. v. Applera Corp. (Enzo II), 780 F.3d 1149 (Fed. Cir. 2015), concerning the proper construction of the claims in U.S. Patent No. 5,449,767, and correctly analyzed the doctrine of equivalents argument of Plaintiffs-Appellants Enzo Biochem, Inc., Enzo Life Sciences, Inc., and Yale University ("Enzo").  The District Court had found that the Federal Circuit's decision in Enzo II applied to all of the claims in the '767 patent, and not just claim 1 as Enzo had asserted, and had rejected Enzo's argument that the claims covered direct detection (in addition to indirect detection) under the doctrine of equivalents.  The Federal Circuit affirmed both determinations by the District Court.

The opinion begins by noting that the Federal Circuit had considered the infringement action between Enzo and Defendants-Appellees Applera Corp. and Tropix, Inc. ("Applera") on three separate occasions over thirteen years.  The dispute began in 2004, when Enzo filed suit against Applera alleging infringement of six patents, including the '767 patent.  The '767 patent is directed to the use of nucleotide probes to detect the presence of a particular DNA or RNA sequence in a sample or to identify an otherwise unknown DNA sequence.  Such detection occurs via hybridization of the probes with the DNA or RNA sequence of interest, wherein hybridization of the probe and target sequence may be directly detected (by using a labeled probe) or indirectly detected (by using a secondary chemical agent that is bound to the labeled probe).

After a jury found that Applera infringed claims 1, 8, 67, 68, and 70 of the '767 patent, Applera appealed, arguing that the District Court had erred in construing the claims to only cover indirect detection.  The Federal Circuit in Enzo II reversed, concluding that "the inventors were claiming only indirect detection," and therefore that the District Court had erred in construing the claims to cover both direct and indirect detection.  On remand, the District Court granted Applera's motion for summary judgment of noninfringement, determining that Enzo II applied to all of the claims of the '767 patent and rejecting Enzo's doctrine of equivalents argument.  Enzo appealed the District Court's judgment to the Federal Circuit.

With respect to Enzo's argument that the District Court incorrectly interpreted the Federal Circuit's decision in Enzo II as applying to all of the claims of the '767 patent, with Enzo asserting that Enzo II should only apply to claim 1, the panel concluded that:

[A]fter carefully parsing our decision, the district court correctly interpreted Enzo II.  As the district court explained, Enzo II consistently refers to the "claims" at issue in that appeal, which extended beyond claim 1 to include claims 8, 67, 68, and 70.  . . .  For example, our opinion in Enzo II, after acknowledging that Enzo had asserted claims 1, 8, 67, 68, and 70, states that the district court "erred in its claim construction by finding that the claims at issue covered direct detection" [emphasis in original].

As for Enzo's argument that Applera infringed claims 1 and 8 under the doctrine of equivalents, the panel notes that "[t]he district court explained that the patent 'describes its method of indirect detection as a superior means of detection as compared to direct detection, with 'detection capacities equal to or greater than products which utilize' direct detection,'" and determined that "Enzo's attempt to reframe its infringement case under the doctrine of equivalents runs headfirst into our decision in Enzo II," where the Federal Circuit found that the claims covered only indirect detection.  As a result, the opinion concludes that "Enzo's attempt to incorporate direct detection methods now through the doctrine of equivalents fails."

Finding that the District Court properly interpreted Enzo II as applying to all of the claims of the '767 patent, and further, that the District Court correctly held that Applera's accused products using direct detection did not infringe Enzo's '767 patent claiming indirect detection, the Federal Circuit affirmed the District Court's judgment.

Enzo Biochem Inc. v. Applera Corp. (Fed. Cir. 2017)
Nonprecedential disposition
Panel: Chief Judge Prost and Circuit Judges O'Malley and Wallach
Opinion by Circuit Judge O'Malley