Before fancying yourself as your own lexicographer, read the cautionary tale told by the U.S. Court of Appeals for the Federal Circuit’s decision in Alnylam Pharmaceuticals, Inc. v. Moderna, Inc., No. 2023-2357. In this case, the court held Alnylam to their narrow definition of “branched alkyl” instead of its ordinary meaning. The narrow definition allowed Moderna’s COVID-19 vaccine SPIKEVAX® to avoid infringement of Moderna’s patents (U.S. Patent Nos. 11,246,933 and 11,382,979).
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Introduction: Conflict between a term’s ordinary meaning and an applicant’s own definition
Generally, words or phrases are given their ordinary and customary meaning in a patent claim. However, an inventor may act as their own lexicographer and define terms inconsistently from the term’s ordinary meaning. While drafting definitions of terms more narrowly than their ordinary meaning may be advantageous at times, such definitions may be disadvantageous if the broader ordinary and customary meaning is needed in litigation.
High Level Summary
In Alnylam’s case, Moderna did not infringe Alnylam’s patents because Alnylam defined its term “Branched Alkyl” too narrowly. The court held Alnylam to its patent definition of “Branched Alkyl” to mean an “alkyl in which one carbon atom in the group (1) is bound to at least three other carbon atoms, and (2) is not a ring atom of a cyclic group,” instead of Alnylam’s later suggested ordinary meaning of “a saturated hydrocarbon moiety that is not a straight chain.” The patent’s definition limited Alnylam’s claims to covering only lipids that comprised tertiary or quaternary carbons. Therefore, Alnylam’s claims could not cover Moderna’s cationic lipid SM-102, which only comprised primary or secondary carbons, as used in SPIKEVAX®.
The court treated the term “Branched Alkyl” as having a binding lexicographic definition because:
(1) the term was located in a “Definitions” section,
(2) the term was in quotation marks,
(3) the definition included the phrase “refers to,” which confers definition intent,
(4) other definitions used non-liming phrases such as “for example” and “including, but not limited to,” and
(5) the definition included the phrase “unless otherwise specified,” which suggests that the rest of the sentence establishes a generally applicable rule or definition.
