The patent eligibility of diagnostic testing methods remains uncertain after the Federal Circuit refused to rehear Ariosa v. Sequenom.1 In Ariosa, the Federal Circuit panel found that Sequenom’s patent on fetal DNA testing was patent ineligible, despite noting the high commercial value of the technology. The panel concluded that the claims failed Mayo’s2 two step analysis for patent eligibility. The claims recited a method for detecting fetal DNA (cffDNA), which can be used for non-invasive genetic testing of the fetus in a variety of applications.

In denying Sequenom’s petition for re hearing en banc, Judge Lourie, with Judge Moore joining, opined that the patent eligibility test in Mayo is too restrictive, but ultimately concluded that the Federal Circuit panel correctly applied the test. Judge Dyk, in a separate concurrence, explained his reasons for reaching the same conclusion. Judge Newman, on the other hand, would have granted rehearing en banc, explaining that “this incorrect decision is [not] required by Supreme Court precedent.”

Judge Lourie’s concurrence expresses concern that a broad range of claims “of this sort” appear in jeopardy because of Mayo, which held that if certain steps merely recite natural laws, the remaining steps must be sufficiently innovative apart from the natural laws. Judge Lourie stated that the claims at issue “contain the nucleus of patent-eligible subject matter” because they “rely on or operate by, but do not recite, a natural phenomenon or law.” Instead, taking maternal serum, separating it, etc. are all physical steps requiring human intervention.3

Judge Dyk’s concurrence takes a different approach, and focuses on claim breadth. Judge Dyk proposes that claims involving laws of nature should be held patent eligible “if the breadth of the claim is sufficiently limited to a specific application of the new law of nature discovered by the patent applicant and reduced to practice . . . .”4 From Judge Dyk’s point of view, the approach would reach the correct balance of allowing the inventor to preclude others from practicing what he/she invented, but not prevent new applications of the natural law by others.5

Judge Newman’s dissent would have granted the petition for en banc rehearing, arguing that the facts of this case diverge significantly from the facts of Mayo and Myriad. In Mayo, argues Judge Newman, the medicinal products and its metabolites were previously known, whereas in the present case, the claims are directed to a new method. Likewise, in Myriad, the claims were directed to the natural phenomenon itself, and the holding was limited to the patent ineligibility of genes and the information they encode.