Branching Misunderstandings: When Chemistry Meets Legalese in Alnylam v. Moderna

The legal clash between Alnylam Pharmaceuticals and Moderna spotlights a fascinating intersection of chemical innovation and patent law. At the heart of the case lies a dispute over the interpretation of specific chemical terms in Alnylam’s patents, which could have significant implications for the biotech industry and patent drafting practices.

The Contested Terrain

Alnylam accuses Moderna’s COVID-19 vaccine, SPIKEVAX®, of infringing on two of its patents—U.S. Patent Nos. 11,246,933 and 11,382,979 (the ’933 and ’979 Patents). These patents describe and claim cationic lipids with defined chemical features, including “branched alkyl” and “branched C10-C20 alkyl” groups. The central legal question revolves around the proper definition of these terms.

In August 2023, the district court adopted Moderna’s narrower interpretation, which defined “branched alkyl” as requiring one carbon atom to be bound to at least three other carbons. Alnylam, however, argues that the terms should have a broader, more inclusive meaning. This dispute has now moved to the Federal Circuit, where the decision could reshape the legal landscape for how patent claims are construed.

The Procedural Backdrop

The dispute began in March 2022, when Alnylam sued Moderna for infringing the ’933 Patent. A second lawsuit followed in July 2022 for the ’979 Patent. These cases were consolidated, along with similar lawsuits Alnylam filed against Pfizer and BioNTech.

The pivotal moment came during a Markman hearing, where Chief Judge Connolly ruled in favor of Moderna, citing a clear lexicographical definition within Alnylam’s ’933 Patent. Based on the patent’s “Definitions” section, the ruling concluded that the term “branched alkyl” required one carbon atom to be bound to at least three others. This interpretation led to a judgment of non-infringement in favor of Moderna, which Alnylam is now challenging on appeal.

Alnylam’s Argument: Broadening the Scope

Alnylam contends that the district court improperly narrowed the terms “branched alkyl” and “branched C10-C20 alkyl.” It argues that these terms should be given their plain and ordinary meanings: a saturated hydrocarbon moiety that is not a straight chain. This broader interpretation includes alpha-branched structures where a carbon atom is bound to two others.

The key points of Alnylam’s argument include:

1. Plain Language and Context Support Inclusion
   Alnylam asserts that the claims, written description, and prosecution history clearly contemplate alpha-branching (carbon atoms bound to two others) as part of the invention. By excluding these structures, the court improperly narrowed the claims.
2. Exclusion of Embodiments Violates Patent Law
   Alnylam argues that the district court’s interpretation excludes specific embodiments disclosed in the patent, violating the principle that claim terms should not be construed to exclude disclosed examples.
3. The “Unless Otherwise Specified” Clause Adds Flexibility
   Alnylam emphasizes the clause “unless otherwise specified” in the patent’s definition of “branched alkyl,” arguing it allows for broader interpretations and supports inclusion of 2-carbon branching.

Moderna’s Argument: Lexicography Rules the Day

Moderna counters that the district court correctly applied the patents’ explicit definition of “branched alkyl.” The ’933 Patent defines the term as an alkyl group in which one carbon atom is bound to at least three others, excluding cyclic structures. This definition, Moderna argues, is unambiguous and legally binding.

Moderna’s key points include:

1. Clear and Unambiguous Lexicography
   The patent explicitly defines “branched alkyl” in its “Definitions” section. Moderna argues that this definition must control unless explicitly overridden, consistent with Federal Circuit precedent, such as Sinorgchem v. International Trade Commission.
2. No Broader Meaning Is “Otherwise Specified”
   Moderna asserts that the phrase “unless otherwise specified” does not introduce ambiguity or broader meanings, as the specification provides no alternative definition.
3. Examples Are Not Controlling
   Moderna contends that claim construction does not require accommodating every example in the specification, particularly when those examples fall outside the claims’ scope.
4. Alnylam’s New Arguments Are Forfeited
   Moderna argues that any new claim construction arguments raised by Alnylam on appeal should be deemed forfeited.

Legal Precedent: A Mixed Picture

Federal Circuit precedent often upholds clear lexicographical definitions, especially when included in a patent’s “Definitions” section. However, there are exceptions where courts have rejected ambiguous or inconsistent definitions. For example:

• In Abbott Laboratories v. Andrx Pharmaceuticals, the court rejected a definition due to conflicting descriptions in the specification.
• In Baxalta Inc. v. Genentech, Inc., the Federal Circuit overruled a narrow claim construction inconsistent with the specification and claim language.

In contrast, no precedent exists for rejecting a clear, express definition simply because it excludes certain disclosed examples.

Lessons for Patent Drafters

This case underscores the importance of precision and consistency in patent drafting. The Federal Circuit’s decision could set new standards for balancing lexicography with contextual interpretations.

The best practices for patent drafting include:

1. Define All Terms Clearly
   Ensure all terms of art are explicitly defined, even those familiar to a person of ordinary skill in the art.
2. Align Definitions and Examples
   Examples in the specification should align with the provided definitions. If an example falls outside a term’s definition, either exclude it or modify it.
3. Anticipate Litigation
   Draft definitions and specifications with future litigation in mind, ensuring clarity and consistency to withstand judicial scrutiny.

Why This Case Matters

The Federal Circuit’s decision in Alnylam v. Moderna could influence how courts interpret patent claims, especially when there’s tension between express definitions and contextual examples. The case serves as a reminder for the biotech and pharmaceutical industries that even the smallest details in patent language can have outsized consequences. As the legal battle unfolds, it underscores the critical interplay between chemistry and legalese in shaping the future of innovation.