Alnylam Stock Plummets 31.67% with 2.10 Billion Shares Traded Ranking 423rd in Volume Amid Legal Victory

On June 20, 2025, Alnylam Pharmaceuticals, Inc. (ALNY) experienced a significant decline in its stock price, dropping by 31.67% with a trading volume of 2.10 billion. This decline placed Alnylam at the 423rd position in terms of trading volume for the day.

In a recent legal development, the Federal Circuit affirmed a district court's claim construction ruling in the case of Alnylam Pharmaceuticals, Inc. v. Moderna, Inc. The court held that Alnylam acted as a lexicographer regarding the claim term "branched alkyl" in the specification. This ruling was based on the clear and specific definition provided in the "Definitions" section of the patent, which included the phrase "refer to," indicating a definitional intent. The court emphasized that a clear reason would be required to depart from this controlling definition, which was not found in the claims, specification, or prosecution history.

This legal affirmation is likely to have a stabilizing effect on Alnylam's patent portfolio, providing clarity and strength to its intellectual property claims. The ruling underscores the importance of precise and unambiguous language in patent specifications, which can significantly impact the outcome of legal disputes. For investors, this development suggests that Alnylam's patents are well-defined and less susceptible to challenges, potentially mitigating future legal risks and enhancing the company's competitive position in the pharmaceutical industry.