August 1, 2020

“Half-Liquid” is Wholly Indefinite

In IBSA Institut Biochemique, S.A. v. Teva Pharmaceuticals USA, Inc., [2019-2400] (July 31, 2020), the Federal Circuit affirmed the district court determination that claims 1, 2, 4, and 7–9 of U.S. Patent No. 7,723,390 were invalid as indefinite under 35 U.S.C. § 112.

Central to the appeal was the parties’ dispute over the construction of “half-liquid,” which appears in independent claim 1. IBSA proposed that the term “half-liquid” should be construed to mean “semi-liquid, i.e., having a thick consistency between solid and liquid.” Teva argued that the term “half-liquid” is indefinite or should be construed as “a non-solid, non-paste, non-gel, non-slurry, non-gas substance.”

The district court determined that IBSA’s proposed construction was not supported by the record, and that a skilled artisan could not otherwise ascertain a reasonably certain meaning for “half-liquid.”

The Federal Circuit began by noting that a claim is invalid for indefiniteness if its language, read in light of the specification and prosecution history, fails to inform, with reasonable certainty, those skilled in the art about the scope of the invention.

The Federal Circuit then turned to the language of the claim to determine whether the meaning of “half-liquid” is reasonably clear. Neither party meaningfully disputed that the claim language did not make the meaning of “half-liquid” reasonably clear. The Federal Circuit found that the claim language clarifies only that a “half-liquid” differs from a liquid.

The Federal Circuit then turned to the specification and prosecution history, which did not help. In fact, the fact that at one time a claim to a semi-liquid depended from the claim to the half-liquid established that half-liquid and semi-liquid were not synonyms.

Because the intrinsic evidence failed to establish the boundaries of a “half-liquid,” the  Federal Circuit turned to the extrinsic evidence, and found no error in the district court’s determination that the extrinsic evidence does not supply “half-liquid” with a definite meaning under § 112.

The Federal Circuit concluded that taken together, the intrinsic and extrinsic evidence fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention, and affirmed the judgment of the district court.


It is important to make sure the meaning of every claim term is clear from the specification, particularly where the claims have been translated from another language.