The US Court of Appeals for the Federal Circuit reversed a district court's claim construction, finding that later-added dependent claims cannot broaden claim scope affirmatively limited by the specification. Cave Consulting Grp., LLC v. Optuminsight, Inc., Case No. 17-1060 (Fed. Cir., Mar. 21, 2018) (Lourie, J). 

Cave owns a patent directed to a method for measuring physician efficiency and patient health risk stratification. The patent describes that a physician's efficiency can be determined by calculating "weighted episode of care statistics" of a peer group and of a physician. The patent explains that the invention "uses an indirect standardization technique for weighing together the episodes within the core group of medical conditions." After Cave sued Optum for infringement, Optum argued that the term "weighted episode of care statistics" should be construed to exclude direct standardization, while Cave argued for a broader claim scope that includes both direct and indirect standardization. Cave contended that indirect standardization was merely one embodiment and the claims were not so limited. The district court adopted Cave's construction, and a jury found infringement by Optum. Optum appealed.

On appeal, the Federal Circuit found that the district court erred in construing the term "weighted episode of care statistics" to include direct standardization. The Court noted that the only support for the district court's broad construction was based on the rationale of claim differentiation to preserve the validity of the dependent claims. In rejecting the district court's finding, the Federal Circuit noted that claim language is not read in isolation and that the patent describes its method as one that employs indirect standardization. Addressing the direct standardization claimed in the dependent claims, the Court found that the only support came exclusively from the description of the prior art methods, and not from the patent specification. The Court also noted that the dependent claims were added after the filing of the original application. The Court noted that if the originally filed application included claims reciting direct standardization, then the later-added dependent claims specifically claiming direct standardization would have lent support for the broader construction. However, in view of the specification's consistently limiting description, the Court concluded that these interpretive canons, despite the later-added dependent claims, cannot overcome the claim scope that is unambiguously prescribed by the specification.

The Federal Circuit also rejected Cave's argument that indirect standardization is merely one embodiment, explaining that the specification affirmatively limits its method of use to one that uses indirect standardization, as opposed to other methods disclosed in the prior art. The Court also rejected Cave's argument that a clear and unmistakable disavowal is required to find disclaimer, explaining that explicit redefinition or disavowal is not required when the description itself is affirmatively limiting.

Finally, the Court concluded that Optum did not infringe as a matter of law. The Court noted that it is undisputed that Optum's method performs direct standardization, and no reasonable jury could find that Optum infringes under the correct construction of "weighted episode of care statistics," which excludes direct standardization.

Practice Note: Avoid limiting description of invention in the specification, and where feasible include dependent claims that rely on prior art methods in the original application.

Claim Differentiation Cannot Be Used To Broaden Narrowly Described Invention

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