Federal Circuit affirmed the ITC’s ruling that an open-ended claim may be construed to have a more limited, enabled scope, if the open-ended claimed range has an inherent upper limit.

The Federal Circuit, FS.COM INC. v. International Trade Commission Corning Optical Communications LLC, 65 F.4th 1373 (Fed. Cir. Apr. 20, 2023), affirmed the International Trade Commission (“ITC”) determination of enablement of U.S. Patent Nos. 9,020,320 and 10,444,456. The Federal Circuit and ITC relied on the general rule that open-ended claims are not inherently improper and may be enabled if there is an inherent, albeit not precisely known, upper limit and the specification enables one of skill in the art to approach that limit. In this case, the Federal Circuit affirmed the ITC’s finding that the recited open-ended density range had an inherent upper limit because a skilled artisan would have understood that the densities substantially above this limit were technologically infeasible based upon expert testimony and the written description of the patents, and that the claims were properly construed as being bounded in scope by this enabled limit.