The Federal Circuit found a pharmaceutical composition patent invalid last week for lack of sufficient clarity, hinging on the term “half-liquid” in the claims. Before drawing this conclusion, the court properly considered the claims, specification, and prosecution history, then looked to extrinsic evidence.

IBSA’s patent in IBSA Institut Biochimique v. Teva Pharmaceuticals USA is directed towards a composition comprising thyroid hormones or salts thereof. Claim 1 recites a capsule consisting of a shell containing a liquid or half-liquid inner phase comprising the hormones or their salts. Teva applied to market a generic version of IBSA’s Tirosint® product, which IBSA’s patent covers. IBSA suggested that “half-liquid” should be a semi-liquid having a consistency between solid and liquid states. Teva asserted that the term is indefinite or should be construed as a non-solid, non-paste, non-gel, non-slurry, non-gas substance. Before the case reached the Federal Circuit, the district court determined that IBSA’s patent was invalid as indefinite and that IBSA’s proposed construction was not supported or ascertainable from the record.

A claim is invalid for indefiniteness if its language, in view of the specification and prosecution history, does not give reasonable certainty about the scope of the invention.

On appeal, the court reviewed intrinsic evidence beginning first with the claim language to determine whether the meaning of “half-liquid” is reasonably clear. From the claim language itself, the court could only determine that “half-liquid” differs from a liquid.  Next, the court examined the specification and determined that “half-liquid” does not include a gel or paste. Furthermore, the construction proposed by IBSA did not appear to be supported by the specification, because it presents a paste as an alternative to a “half-liquid.” Therefore, a paste cannot be a type of “half-liquid” in the same patent.

The court then examined the prosecution history. The patent claims priority to an Italian application. IBSA asserted that the term “semiliquido,” which translates to “semi-liquid,” appears in the Italian application to describe components that are described as “half-liquid” in the U.S. patent and, therefore, a skilled artisan would equate “half-liquid” and “semi-liquid.” Teva asserted that the claim language of claim 1 of the Italian application and claim 1 of the U.S. patent differ. The U.S. patent includes a fourth embodiment not found in the Italian application. The Italian application does not use the term “gel.” The court determined that the different use of the words means that the Italian application and U.S. patent have different scope. When discrepancies exist between a foreign priority document and a U.S. filing, the court noted, it may be proper to view the discrepancies as intentional. During prosecution, a pending claim recited the term “half-liquid” and another claim depending therefrom recited the term “semi-liquid.” The latter was removed during prosecution. From this timeline, the court indicated that the applicant was aware of both terms, and elected to use “half-liquid” to refer to something different.

Having concluded that the intrinsic evidence fails to establish boundaries of the term “half-liquid,” the court turned to examining extrinsic evidence. The court noted that IBSA failed to identify scientific dictionaries that contained the term “half-liquid.” The four patents IBSA cited that use the term “half-liquid” are not informative in the context of the patent at issue. IBSA’s expert also could not clearly define the boundaries of the term “half-liquid.” The court concluded that the extrinsic evidence does not provide any definite meaning to the term “half-liquid.”

Thus, the court affirmed the district court’s decision and held that, “the intrinsic and extrinsic evidence fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.”