Recently, the Federal Circuit denied en banc review of a panel decision invalidating a medical diagnostic method in a move that could signal a turning point in the continued struggle to define patent eligible subject matter. In Ariosa Diagnostics, Inc. v. Sequenom, Inc., No. 14-1139 (Fed. Cir. Dec. 2, 2015), the court affirmed the panel's holding that Sequenom's patent on a method of detecting paternally-inherited fetal DNA in maternal blood samples and performing a prenatal diagnosis based on that DNA is invalid as directed to non-statutory subject matter under 35 U.S.C. § 101.

While the facts of the case are otherwise unremarkable and triggered a straightforward application of Mayo Collaborative Services v. Prometheus Laboratories, Inc., 132 S. Ct. 1289 (2012), of interest to practitioners is language used in the various concurrences that seems to openly question the wisdom of highly restrictive tests for patent eligibility.

Though the court felt compelled to apply Mayo and struck down the patent on those grounds, both Judge Lourie and Judge Dyk raised concerns that the currently applicable tests for subject matter eligibility could discourage innovation and delay the development of new diagnostic methods in the life sciences. Citing arguments made by Sequenom and various amici, Judge Lourie noted that the court's decision implicated a possible "crisis of patent law and medical innovation," and could place "a broad range of claims... in serious jeopardy." Ariosa Diagnostics, at 4. He concluded that "it is unsound to have a rule that takes inventions of this nature out of the realm of patent eligibility on the grounds that they only claim a natural phenomenon plus conventional steps, or that they claim abstract concepts."

Similarly, while acknowledging that the framework outlined in Mayo and Alice Corp. v. CLS Bank International, 134 S. Ct. 2347 (2014), is an "essential ingredient of a healthy patent system," Judge Dyk also called into question the wisdom of overly restrictive eligibility tests. He took issue with the rigidity of Mayo, writing that a "too restrictive test for patent eligibility under 35 U.S.C. § 101 with respect to laws of nature... may discourage development and disclosure of new diagnostic and therapeutic methods in the life sciences, which are often driven by discovery of new natural laws and phenomenon." Ariosa Diagnostics, at 2. Judge Dyk called for "further illumination of the scope of Mayo" but acknowledged that such guidance must come from the Supreme Court.

Though the case addressed the viability of specific medical diagnostic claims, its lessons can be generalized well beyond the life sciences realm. Ariosa suggests an inflection point in the Federal Circuit's approach to defining patent eligible subject matter. Tasked with implementing often vague Supreme Court decisions regarding subject matter eligibility, the Federal Circuit appears to be calling for more explicit guidance that would strike a reasonable balance between promoting innovation and preserving competition. Whether the Supreme Court obliges this request remains to be seen, but in the meantime, patent practitioners can take comfort in the fact that they are not the only ones struggling to navigate the murky waters of § 101.

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