Jushutterstock_147164960dge Newman’s dissent in Enzoidemonstrates that the Federal Circuit is struggling with how much deference to give to a district court’s claim construction in view of the Supreme Court’s ruling in Teva.ii

In Enzo, the majority found that the district court’s claim construction of the phrase “at least one component of a signaling moiety,” was incorrect when reviewing the intrinsic evidence and taking into account the ordinary and customary meaning of the term “component.”iii The court pointed to a number of instances in the specification where the only examples of “signaling moiety” required at least two components and thus the claims encompassed only indirect detection.iv This was contrary to the district court’s claim construction, which determined that direct detection of the signaling moiety without an additional compound was also encompassed by the claims.v

However, the majority seemed to gloss over the specific factual findings supported by expert testimony that, in fact, at least one example in the specification did support a construction that “at least one component” could mean a single signaling moiety.iv Instead, the Federal Circuit noted that “this sole factual finding does not override our analysis of the totality of the specification.”vii In addition, rather awkwardly, the Federal Circuit dismissed the use of claim differentiation used by the district court to support its holding, stating that a dependent claim cannot broaden claim 1.viiiThis conclusion, however, came only after the majority first found claim 1 should have been construed more narrowly.

In the dissent, Judge Newman identifies several instances where the majority failed to follow the Supreme Court’s holding in Teva. For instance, she argues that the majority opinion “ignore[s] the testimony and the district court’s findings and the jury verdict based on the evidence at trial.”ix As argued by Judge Newman, the majority reviewed all aspects of the claim construction under a de novo standard, rather than reviewing the findings of fact that the district court found critical to its decision for clear error.x

With Enzo, it would appear that the Federal Circuit is reluctant to let go of its hold on the review of claim construction. Perhaps when the district court relies more heavily on expert testimony, its claim construction would be given more deference. But according to Judge Newman, the majority “show[s] error in neither fact nor law in the court’s findings and conclusions,”xi which makes it difficult to predict the court’s reasoning in subsequent claim construction rulings.

i Enzo Biochem, Inc. v. Applera Corp., 780 F.3d 1149, 1157-59 (Fed. Cir. 2015).
ii Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831 (2015).
iii Enzo, 780 F.3d at 1154.
iv Id. at 1155.
v Id. at 1153.
vi Id. at 1155-56.
vii Id. at 1156.
viii Id.
ix Id. at 1159.
x Id.
xi Id.