Astrazeneca AB v. Mutual Pharmaceutical Co. (Fed. Cir. 2004): Specification king in claim construction, despite the absence of a clear lexicography or disavowal.
By Dr. Baltazar Gomez,
Astrazeneca sued Mutual for patent infringement based on submission of an ANDA to the FDA. The patent in question was Astrazeneca’s U.S. Patent No. 4,803,081 (the “‘081 patent”) directed to extended-release formulations for felodipine using “a semi-solid or liquid nonionic solubilizer.” Mutual’s ANDA was for extended-release felodipine using a co-solvent as a solubilizer. The question analyzed by the CAFC was whether the definition of “solubilizer” in the ‘081 patent takes priority in claim construction or if the ordinary meaning of the term, as determined from sources such as treatises and dictionaries, controls claim construction in the absence of clear lexicography or disavowal.
Both parties agreed that “solubilizer” embraced surface active agents (or surfactants), co-solvents, and complexation agents. But the CAFC accepted Mutual’s argument that the Patentees acted as their own lexicographers and limited the scope of “solubilizer” to surfactants. The ‘081 patent states that “[t]he solubilizers suitable according to the invention are defined below”, and later, states that “[t]he solubilizers suitable…are semi-solid or liquid non-ionic surface active agents.” The ‘081 patent also describes micelle structures as features of the claimed formulation. Astrazeneca argued that these statements referred to preferred embodiments of suitable solubilizers. The CAFC disagreed because the ‘081 patent did not state, for example, “a solubilizer suitable for,” but in fact, the specification stated “the solubilizers suitable for.” The CAFC noted that the language of the ‘081 patent provided a strong signal of lexicography that clearly disavowed nonsurfactant solubilizers.
Thus, the CAFC held that Mutual did not infringe Astrazeneca’s patent because the ‘081 patent limited “solubilizer” to surfactants and overcame any ordinary meaning of the term derived from any other evidence. The CAFC followed a long line of cases that indicate that a patent’s specification is the primary source for determining claim meaning. Where the ordinary meaning of a claim is evident, the inventor’s written description of the invention is relevant only insofar as it provides clear lexicography or disavowal of the ordinary meaning.
Note: Dr. Baltazar Gomez is a law clerk at McDonnell Boehnen Hulbert & Berghoff LLP in Chicago. Dr. Gomez obtained his PhD in biochemistry from the University of Texas and researched biochemistry and molecular biology as a PostDoc at Cornell. He is now a law student at DePaul.