Under 35 U.S.C. § 101, only a “new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof” is patent eligible. Long-recognized judicial exceptions to § 101 bar patenting laws of nature, natural phenomena, and abstract ideas. Since the U.S. Supreme Court’s decisions in Mayo and Alice developed the exceptions, courts, commentators, and patent practitioners have been seeking clarification on the contours of patent eligibility under 35 U.S.C. § 101.
In 2019, the U.S. Congress was poised to hand those constituencies exactly that, with Senators Thom Tillis and Chris Coons introducing a draft bill that would largely abrogate the judicial exceptions to patent eligibility. But subsequent hearings made clear that key stakeholders did not agree on the proposed changes, leading Senator Tillis to conclude that “absent stakeholder consensus I don’t see a path forward for producing a bill—much less steering it to passage—in this Congress.”
Also in 2019, the U.S. Patent and Trademark Office (USTPO) significantly revised its examining procedures for patent eligibility by incorporating the U.S. Court of Appeals for the Federal Circuit’s post-Mayo case law on § 101. While the revisions potentially help patent applicants and examiners, the Federal Circuit has previously expressed resistance to the USPTO’s interpretation of judicial exceptions to § 101, making it unlikely that the guidance will affect litigated issues of patent eligibility.
Meanwhile, the Supreme Court has not shown interest in clarifying its patent eligibility case law: In January 2020, the Court declined to hear several cases on patent eligibility. The move establishes the Federal Circuit as the best situated institutional player to address the inconsistencies of the Supreme Court’s § 101 jurisprudence. Yet, the Federal Circuit’s efforts to clarify the post-Mayo line of cases in the biotechnology field have been ineffective at best, and incompatible with Supreme Court precedent at worst. In the chaos, one clear line has emerged: method of treatment claims are patent eligible, while method of diagnosis claims are not.
In applying the Mayo framework to diagnostic technologies, the Federal Circuit has taken Mayo too literally. Rather than refining Mayo’s broad principles, the Federal Circuit’s test is basically: “Does it smell like Mayo?” This Comment argues that this approach is inconsistent with the Mayo Court’s articulation of the law of nature exception to § 101. Diagnostic technologies should not be per se patent ineligible, even under Mayo’s broad framework. In applying Mayo to diagnostic technologies in particular, the Federal Circuit must find patent eligibility by interpreting claims as a whole where the patentee has discovered a novel way of measuring a biomarker.
Part I provides a brief overview of Mayo and the disparate approach the Federal Circuit has taken towards treatment and diagnostic inventions. Part II criticizes the approach for relying too much on—and misinterpreting—Mayo’s strange factual backdrop and ill-conceived dicta. This approach can also be attributed to another error: importing the search for improvements from Step 2 to Step 1 of the Mayo framework, much to the detriment of diagnostic methods. Part II also advances a better approach that the Federal Circuit could undertake: Specifically, it emphasizes the need to consider claims as a whole to ensure that diagnostic methods that include non-routine steps as claim limitations are patent eligible.