“Half-liquid” held indefinite by the Federal Circuit – IBSA v Teva

IBSA v Teva

Though IBSA provided direct and indirect evidence that one of ordinary skill in the art would understand the term to be a synonym of “semi-liquid,” the Federal Circuit discounted it.  The Court instead found support in a prosecution history where the term was not directly at issue.


IBSA is the assignee of US Patent 7,723,390 (“the ‘390 patent”) directed to thyroid hormone compositions. Teva Pharmaceuticals filed an ANDA application, which prompted IBSA to sue Teva for infringment. Teva countered that claims 1, 2, 4 and 7-9 of the ‘390 patent were invalid as indefinite under 35 USC §112.  The District Court sided with Teva, and IBSA appealed.

The issue on appeal was the construction of the phrase “half-liquid” which appears in independent claim one as follows:

A soft elastic capsule consisting of a shell of gelatin material containing a liquid or half-liquid inner phase…

After reviewing the intrinsic and extrinsic evidence, the Federal Circuit affirmed the District Court’s finding that the term “half-liquid” was indefinite, and holding the ‘390 patent invalid.

Evidence provided by IBSA was held insufficient

This was the result even though IBSA had provided intrinsic evidence in the form of i) the priority application, which arguably supported an interpretation of “half-liquid” to be a synonym of “semi-liquid”, ii) the description of several liquid or half-liquid vehicles in the specification of the ‘390 patent and extrinsic evidence in the form of dictionary definitions, use of the term in patents assigned to others and expert testimony interpreting the same.

With respect to the priority application, the District Court found, and the Federal Circuit agreed, that the interchangeable usage of “half-liquid” and “semi-liquid” between the ‘390 patent and its Italian priority application were construed to be a conscious choice on the part of IBSA, “implying that the different word choice has a different claim scope.”  The Court even had a cite for this – Abbott Labs v Sandoz, Inc. 566 F.3d 1282, 1290 (Fed. Cir. 2009) (“when discrepancies between a foreign priority document and the US filing exist, it may be proper to view the discrepancies as intentional.”).  The content included in the specification was held to provide “little guidance” regarding the meaning of the term “half-liquid.”

The Court was similarly unimpressed with IBSA’s extrinsic evidence.  Specifically, the Court found the dictionary definition unpersuasive, as it was from a “non-scientific” dictionary.  The other patents were deemed unhelpful as they used the term “half-liquid” in a different context, and IBSA’s expert was not a convincing witness and/or relied upon the extrinsic evidence deemed deficient.

Prosecution history was construed against IBSA’s position

The factors that contributed to the Court’s finding that “half-liquid” was indefinite are also interesting.  Specifically, the Court was persuaded by arguments made by IBSA during the prosecution of the ‘390 patent not directly in response to a 112 rejection of the term.

First, the District Court found it informative that IBSA had introduced a dependent claim using the term “semi-liquid.” This claim depended on an independent claim that used the term “half-liquid.” IBSA later canceled the claim, but this portion of the prosecution history was construed as evidence that IBSA did not mean “semi-liquid” when the term “half-liquid” was used, or, that IBSA knew of the term “semi-liquid” and elected to use the term “half-liquid” to mean something different.

Second, in overcoming an obviousness rejection, IBSA argued that the claimed invention “is not a macromolecular gel-lattice matrix” and also that the claimed invention “is not a high concentration slurry.” The District Court determined that, while the full scope of these disclaimers was not clear, IBSA had disclaimed some portion of the claim’s scope that might otherwise qualify as a “half- liquid.”

The ‘390 specification’s citation to pharmaceutical references which used the term “semi-liquid” were also deemed not to show that “half-liquid” meant “semi-liquid.”  Instead, the court reasoned that such citations showed that IBSA new of the term “semi-liquid” and intentionally chose not to use it.