By: Katherine Rubino

On February 6th, 2019 the U.S. Court of Appeals for the Federal Circuit (CAFC) in Athena Diagnostics, Inc., v. Mayo Collaborative Services, held that diagnostic method claims were patent ineligible.

Athena Diagnostics is the exclusive licensee of the ‘820 patent, directed at methods for diagnosing neurological disorders, by detecting antibodies to a protein named muscle-specific tyrosine kinase (MuSK). The method covered by the ‘820 patent is particularly useful in diagnosing myasthenia gravis, a neurological disorders that can cause muscle weakness, drooping eyelids, double vision, and slurred speech. Myasthenia gravis is an autoimmune disease that causes a patient to produce antibodies against his or her own acetylcholine receptors. Some patients with myasthenia gravis do not produce antibodies to acetylcholine receptors but instead produce antibodies to MuSK. The method described in the ‘820 patent is useful for detecting the 20% of myasthenia gravis patients who produce the MuSK antibodies.

The District Court analyzed claims 7-9 of the ‘820 patent, applying the test for subject matter eligibility established by the Supreme Court in Mayo Collaborative Services v. Prometheus Laboratories, Inc. In Mayo v. Prometheus, the Supreme Court unanimously found that claims directed to a method of giving a drug to a patient and measuring the metabolites of that drug to then adjust a patient’s dose, was not patent eligible subject matter. The Supreme Court held that the correlation between drug metabolites and dose adjustments were directed towards “natural laws.” The Supreme Court further reasoned that a law of nature is itself unpatentable, and the application of a law of nature is unpatentable if the application relies upon elements already known in the art.

In Athena v. Mayo, the District Court concluded that the claims in the ‘820 were directed towards a law of nature. On appeal, the CAFC affirmed, reasoning that “claiming a natural cause of an ailment and well-known means of observing it is not eligible for patent because such a claim in effect only encompasses the natural law itself. But claiming a new treatment for an ailment, albeit using a natural law, is not claiming the natural law.”

The CAFC then turned to the rationale set forth in Alice Corp. v. CLS Bank International to examine whether the elements of each claim both individually and as an ordered combination transform the claims into patent-eligible subject matter. Athena argued that the claims provide an inventive step that includes man-made molecules. Athena pointed out that the method described in the ‘820 patent was the first one to detect MuSK antibodies. Mayo argued that the method steps described in the ‘820 patent were commonly known in the art.

The CAFC considered all arguments and affirmed the ruling of the District Court, finding that claims 6-9 of the ‘820 patent are patent ineligible under ⸹101. This case is significant in that the majority and the corresponding dissenting opinion highlight the split opinion among the justices in this area. While the majority opinion upheld and applied prior cases decided at the Supreme Court, the dissenting opinion highlighted the hamper this decision places on innovation in the chemical arts field. Judge Newman declared that “the public interest is poorly served by adding disincentive to the development of new diagnostic methods.” Going forward, it will be interesting to see if further cases provide subsequent developments in this area.

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