Sequenom’s More Specific Claims Survive

The U.S. Court of Appeals for the Federal Circuit took another look at Sequenom’s techniques for detecting fetal blood cells in a maternal blood sample. In Illumina Inc. & Sequenom, Inc. v. Ariosa Diagnostics, Inc., No. 2019-1419, 2020 U.S. App. LEXIS 8327 (Fed. Cir. March 17, 2020), the Court held that specific, unconventional acts in the claims survived the patent-eligibility challenge.

Prior Decision

In its prior decision (Ariosa v. Sequenom, 788 F.3d 1371 (Fed. Cir. 2015)), the Federal Circuit had said it was constrained by precedent to find the claims directed to a natural phenomenon ineligible for patent protection. The claims at issue in the earlier litigation generally required three steps: (1) obtain a maternal blood sample, (2) amplify paternally inherited DNA from the sample, and (3) detect the paternally inherited DNA identifying the fetus’s DNA in the sample. There, the Court emphasized that the existence of fetal DNA, and the paternally inherited markers in that DNA, were naturally occurring within a mother’s blood. It was undisputed by the parties that the lab techniques used to draw blood, amplify targeted DNA, and detect amplified DNA were conventional. The only potential point of novelty was applying those techniques to a maternal blood sample to identify fetal DNA in that sample. The majority said it was constrained by the Supreme Court’s Mayo decision to invalidate the claims as being directed to a patent-ineligible natural phenomenon.

However, the panel recognized that the claimed techniques were an important breakthrough that we should incentivize with patent rights. The conventional wisdom at the time was that any trace fetal DNA in a pregnant mother’s blood would be scant. As a result, tests that needed to be run using fetal DNA required extracting blood directly from the fetus utilizing a needle puncturing through the uterus. This procedure was dangerous, sometimes fatal, to the fetus. Sequenom’s discovery enabled DNA testing for the fetus to be performed from a maternal blood sample drawn using safe, standard blood draw techniques.

New Decision

In the more recent litigation, Sequenom’s patent included additional steps: (1) performing size discrimination on extracullular circulatory DNA fragments and (2) removing DNA fragments greater than about 300 or 500 base pairs. Sequenom had made a follow-on discovery that the fetal DNA in the bloodstream of a pregnant mother had size characteristics distinguishing it from maternal DNA.

Unlike the claims from the prior case, the asserted claims in this case required the performance of unconventional steps tied to the discovery. While Sequenom had not invented size discrimination writ large, it applied size discrimination targeting a specific number of base pairs in a way that had not been done before. This rendered the claims similar to the claims confirmed patent-eligible in Cellzdirect. There, the inventors had not invented freezing cells to form a sample of adequate size. However, they claimed a refreezing step upon discovering that certain cells would survive multiple freeze-thaw cycles. This discovery went against the accepted wisdom that refreezing would damage the cells, making them unusable for samples. Tying the claims to a specific, unconventional act ensured they would survive a patent-eligibility challenge.

The Dissent

Judge Reyna wrote a dissent, arguing that the panel majority’s decision was wrong. He argued the majority had mischaracterized what the advance really was. The inventors had not come up with size discrimination for DNA testing; they merely applied that known technique to their discovery of the naturally occurring differences in numbers of base pairs between extracellular fetal DNA and maternal DNA in a maternal blood sample. As a result, he argued that the claims should have been invalidated because they were directed to a patent-ineligible natural phenomenon.

Tips for Practitioners and Inventors

When an invention approaches the line between an unpatentable natural phenomenon or abstract idea and a patentable application, practitioners should take care to dig deep into the specifics of the invention. This starts with a thorough interview, exploring the problems faced by the inventor(s) along the way, the solutions tried, and all the specifics that enable success. Taking care to protect any information that may be more valuable when kept as a trade secret, as much of the foregoing detail as possible should be included in the patent application. This will provide a robust disclosure with many options for amending the claims, granting flexibility in strategies for obtaining valuable, valid claims. Practitioners should also take care to keep characterizations regarding the problems and solutions that were known to the inventor(s), but not known generally, out of the background section to avoid making any untoward admissions regarding what was in the prior art. Finally, the unconventional acts taken as a result of any discoveries made by the inventors should be emphasized, including presenting at least one in the independent claims, to strengthen the claims against a subject-matter eligibility challenge.

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