The Definition of “Half-Liquid” Is Only Half Baked

| Karen Cassidy Selvaggio


Before Prost, Reyna, and Hughes. Appeal from the District Court of Delaware

Summary: A term may be indefinite when the proposed construction is not supported by the record and the meaning is not reasonably ascertainable from the record.

Teva Pharmaceuticals USA, Inc. (“Teva”) sought to market a generic version of a drug sold by IBSA Institut Biochimique, S.A., Altergon, S.A., and IBSA Pharma Inc. (collectively “IBSA”). In response, IBSA sued Teva for infringement of its U.S. Patent No. 7,723,390 (the ’390 patent) in the U.S. District Court for the District of Delaware. The District Court found the ’390 patent invalid because the claimed term “half-liquid” was indefinite. IBSA appealed.

Reviewing determinations about legal standards and intrinsic evidence de novo and factual findings based on extrinsic evidence for clear error, the Federal Circuit affirmed the District Court’s decision. In particular, the Federal Circuit could not construe “half-liquid” to mean “semi-liquid,” as IBSA had argued. First, the Federal Circuit determined that the meaning of “half-liquid” was not reasonably clear from the claims. Next, turning to the specification, the Federal Circuit found that language listing “half-liquid” separately from gels and pastes indicated that a “half-liquid” is not necessarily a gel or paste. IBSA’s construction, however, encompassed gels and pastes as “half-liquids.” Looking next at the prosecution history, the Federal Circuit explained that, while an Italian patent – to which the ’390 patent claimed priority – used the word “semiliquido” or “semi-liquid” similarly to the ’390 patent’s use of “half-liquid,” the terms could not have the same meaning in the ’390 patent. The ’390 patent used both the term “half-liquid” and the term “semi-liquid” in its claims. Moreover, differences in language between the certified translation of the Italian application and the ’390 patent suggested that the discrepancy in usage was intentional, implying that the different word choice of “half-liquid” and “semi-liquid” results in a different scope. Finally, turning to extrinsic evidence, the Federal Circuit highlighted the inability of IBSA’s expert witness to define “half-liquid” and the term’s absence from technical dictionaries. Accordingly, the Federal Circuit found no clear error in the District Court’s determination that the record does not supply “half-liquid” with a definite meaning and affirmed the judgment.

Editor: Paul Stewart