Federal Circuit Rejects Patentability of Test for Fetal DNA in Maternal Circulation

On June 12, 2015, the Court of Appeals for the Federal Circuit (CAFC) held the DNA detection method claims at issue in Ariosa v. Sequenom invalid as directed to non-patentable subject matter.  The decision is the latest in a line of recent Supreme Court and CAFC decisions constricting the scope of patentable inventions in the fields of biotechnology and diagnostics.

At issue in Ariosa was the validity of U.S. Patent No. 6,258,540, which claimed methods for detecting fetal DNA circulating in the bloodstream of the mother.  These methods allowed physicians to determine, for example, the gender of a fetus by testing a blood sample from the mother rather than resorting to the riskier methods of determining gender that had been used previously.  The claims included the steps of amplifying and detecting the presence of paternal DNA in the mother’s blood sample.

The CAFC held that the claims in Ariosa invalid under 35 U.S.C. § 101 of the patent laws because the claims were not directed to patent eligible subject matter.  The Federal Circuit applied a two-step test for patent eligibility that it derived from the Supreme Court’s decision in Mayo v. Prometheus.  In step one of the Mayo test, the court asked whether the claim is directed to a patent-ineligible concept, such as a law of nature or an abstract idea.  In step two, the court asked whether the claim includes other limitations providing an “inventive concept” such that the claim is directed to “significantly more” than the patent-ineligible concept itself.

Following this rubric, the CAFC first concluded that the presence of fetal DNA in a woman’s blood sample is a natural phenomenon, and not itself patent-eligible.  Second, the CAFC concluded that amplifying and detecting the DNA are routine, conventional steps, even if not previously used to detect paternally-inherited fetal DNA in a blood sample from the mother.  While acknowledging that the claimed method represented a “positive and valuable contribution to science,” the CAFC nevertheless found that the claims failed the two-step Mayo test and were therefore invalid.

This decision highlights the vulnerability of certain patents that are potentially important to the biologics industry.  Patents like those in Ariosa and Mayo, relating to diagnostics can be at significant risk, even when directed to testing a newly-discovered biomarker, or a biomarker newly discovered to be found in a previously unappreciated place.  Because a companion diagnostic is necessarily developed after its corresponding therapeutic is discovered, and would typically lead to later-expiring patents, limitations on patent-eligibility may leave an innovator with fewer options for protecting its inventions and potentially facilitating competitive entry.