As Congress weighs proposed changes to patent eligibility law, WilmerHale Partner Arthur Coviello, Counsel Chris Cherry, Ph.D., and Associate Jeffrey Wu are helping practitioners better understand one of the most consequential frameworks governing the patentability of composition-of-matter claims. In "How 'Markedly Different' Test Shapes Patent Eligibility Debate," published by Law360, the authors examine how courts and the US Patent and Trademark Office have applied the "markedly different characteristics" test first articulated by the US Supreme Court in Diamond v. Chakrabarty.
Set against the backdrop of the July 2026 Senate Judiciary Committee hearing on the proposed Patent Eligibility Restoration Act (PERA), the article traces how the test has been applied across decades of case law—generally distinguishing compositions found eligible for their manmade altered structures or new or enhanced functional properties and potential for significant utility from those deemed ineligible for merely isolating or synthetically replicating natural products. The authors also explain how the USPTO applies the test and offer practical guidance for practitioners.
"As efforts in Congress to alter patent eligibility law continue, practitioners drafting or defending composition of matter claims should focus on clearly articulating how the claimed composition departs from its natural counterpart in structure or function," the authors write. Where structural distinctions are less apparent, they advise, practitioners should emphasize new or enhanced functional properties with the potential for significant utility.
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