The Significance Of Claim Language In The Patent Validity - IBSA Institut Biochimique Vs S.A.V. Teva Pharmaceuticals

The U.S. Court of Appeals for the Federal Circuit (CAFC) latest decision, in IBSA Institut Biochimique, S.A. v. Teva Pharmaceuticals USA, Inc., affirmed a District Court's decision that the asserted claims relating to a pharmaceutical composition were invalid as indefinite under 35 U.S.C §112.


IBSA is the assignee of the orange book listed patent, US 7,723,390 (‘390 patent) claimingTirosint® product, which is a soft gel capsule formulation of the active ingredient levothyroxine sodium. The ’390 patent claims priority from the Italian Patent Application, which is in the Italian language.IBSA sued Teva for the infringement of ‘390 patent in continuance to the Teva’sANDA of the Tirosint® product.


patent validity invalidityCentral to this appeal is the parties’ dispute over the construction of the term “half-liquid,” which appears in independent claim 1 of ‘390 patent. Claim 1 of the ‘390 patent is shown below.

  1. A pharmaceutical composition comprising thyroid hormones or their sodium salts…..: a) a soft elastic capsule ……… containing a liquid or half-liquid inner phase comprising ……..ethanol, said liquid or half-liquid inner phase being …….., or b) a swallowable uniform soft-gel matrix ……… 0.001 and 1% by weight of the said matrix.

(Emphasis added.)

IBSA proposed that "half-liquid" should be construed to mean "semi-liquid" i.e., to be interpreted as "having a thick consistency between solid and liquid."  On the other hand, Teva contended that the term"half-liquid" is indefinite or should be construed to mean "a non-solid, non-paste, non-gel, non-slurry, non-gas substance."


(I) Analysis of Intrinsic Evidence

By looking first at the claim language of the ‘390 patent, the Federal Circuit said that the claim language does not make the meaning of “half-liquid” reasonably clear. Therefore, the Federal Circuit concluded that the claim language clarifies only that the term “half-liquid” differs from the liquid.

Moving next to the specification, the Federal Circuit agreed with the district court that numerous passages containing disjunctive lists designate that the term“half-liquid” is an alternative to the other members of the list, including pastes and gels.  However, pastes and gels have a thick consistency between a liquid and a solid and would be included in IBSA’s proposed construction. Such inclusion creates uncertainty as to the boundaries of the term, “half-liquid”. Thus, the Federal Circuit concluded that the specification does not help clarify the boundaries of the term “half-liquid.”

Turning next to the prosecution history, the Federal Circuit agreed with the district court that there are substantial differences between the Italian patent application and the‘390 patent. Accordingly, the substantial differences would indicate POSA that usage of“half-liquid” and “semiliquid” in the ’390 patent and the Italian application to be intentional, implying that the different word choice has a different scope. Furthermore, the Federal Circuit said that the deletion of a dependent claim reciting the term “semi-liquid” confirms an intentional difference between the terms, “semi-liquid” and “half-liquid.”

(II) Analysis of Extrinsic Evidence

Finally, turning to extrinsic evidence, including dictionary definitions, other patents, and expert testimony, the Federal Circuit agreed with the district court that the extrinsic evidence does not supply “half-liquid” with a definite meaning under 35 U.S.C §112.

Applying the Supreme Court decision of Nautilus, Inc. v. Biosig Instruments, Inc., on the indefiniteness standards, the Federal Circuit held that the intrinsic and extrinsic evidence failed to inform, with reasonable certainty, those skilled in the art about the scope of the invention.


This case clearly shows that the undefined terms in the claims of the patent may become indefinite when the terms do not have well-established meanings in the art and the proposed construction of the terms is not supported by the specification. In addition, this case also indicates the importance of the proper translation of the patent specification while filing a patent application with the patent offices.

About the author: Mr. Dhakshina Moorthy, a legal practitioner at Global Patent Filing. In case of any queries please contact/write back to us at

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