In what may be another blow to diagnostic patents, the US Court of Appeals for the Federal Circuit affirmed the patent ineligibility of claims that it held to be directed to detecting natural phenomena by conventional techniques. CareDx, Inc. v. Natera, Inc., Case No. 2022-1027 (Fed. Cir. July 18, 2022) (Lourie, Bryson, Hughes, JJ.)
CareDx is the exclusive licensee of three Stanford University patents directed to diagnosing or predicting organ transplant status by using methods to detect a donor’s cell-free DNA (cfDNA). When an organ transplant is rejected, the recipient’s body destroys the donor cells, releasing cfDNA from the donated organ’s dying cells into the blood. Detecting the naturally increased levels of donor cfDNA (due to the deteriorating organ condition) can be used to diagnose the likelihood of an organ transplant rejection.
The representative claims were summarized as having four steps for detecting a donor’s cfDNA in a transplant recipient:
- “Obtaining” or “providing” a “sample” from the recipient that contains cfDNA
- “Genotyping” the transplant donor and/or recipient to develop “polymorphism” or “SNP” “profiles”
- “Sequencing” the cfDNA from the sample using “multiplex” or “high-throughput” sequencing, or performing “digital PCR”
- “Determining” or “quantifying” the amount of donor cfDNA.
CareDx filed two lawsuits, one alleging that Natera’s kidney transplant rejection test infringed the patents, and another alleging that Eurofins Viracor’s various organ transplant rejection tests infringed one of the patents. Natera and Eurofins moved to dismiss the complaints for failing to state a claim because of a lack of patent-eligible subject matter under 35 U.S.C. § 101. The magistrate judge who reviewed the motions recommended that they be denied, finding that the claims were a “purportedly new, unconventional combination of steps” to detect natural phenomena. Although the recommendation was vacated with regard to Natera because the complaint was amended, the district court adopted the magistrate’s recommendation as to Eurofins with modified reasoning that the patent “specifications raise doubts about the patents’ validity” by suggesting that the steps were neither new nor unconventional. Still, the district court was wary of ruling prematurely and denied the motion so that the parties could conduct discovery to develop the record on what was considered conventional in the art.
Following expert discovery relating to § 101 eligibility, Natera and Eurofins moved for summary judgment on patent ineligibility. The district court denied summary judgment, citing a factual dispute as to the conventionality of the techniques for performing the claimed methods. Natera and Eurofins moved for certification of interlocutory appeals of the district court’s denial. After conferring with the parties, the district court agreed to reconsider its decision in view of case law raised in the certification motion. After reconsideration, the district court granted the summary judgment motions of ineligibility, finding that the asserted claims were directed to the detection of natural phenomena—specifically, the presence of donor cfDNA in a transplant recipient and the correlation between donor cfDNA and transplant rejection—and concluding that based on the specification’s many admissions, the claims recited only conventional techniques.
CareDx appealed, arguing that under the Supreme Court’s Alice/Mayo two-step test, the patents’ claimed improved measurement methods were superior to “inadequate prior art measurement techniques.” CareDx argued that the district court’s step one analysis (whether the claims are “directed to” a law of nature or natural phenomenon) was improper because the district court collapsed its step one analysis with its step two analysis centering on conventionality (instead of properly examining whether the limitations of the claim apart from the law of nature or natural phenomenon, considered individually and as an ordered combination, “‘transform the nature of the claim’ into a patent-eligible application”). CareDx argued that under a proper step two analysis, using digital PCR and next-generation sequencing to identify and measure donor-specific SNPs was an inventive breakthrough, and a specific and useful application claimed by the patents. CareDx also made procedural arguments, pointing to the court’s initial acknowledgment that there was a factual dispute as to the conventionality of the claimed techniques.
Natera responded that the asserted claims were directed to detecting natural phenomena—the presence of an organ donor’s cfDNA in the blood of a transplant recipient and the correlation between elevated levels of that cfDNA and organ transplant rejection. It also argued that the claims recited performing this detection using only existing conventional collection and measurement techniques without modification and noted admissions of conventionality in the specification. Natera argued the asserted claims were indistinguishable from other diagnostic method claims that the Supreme Court found ineligible in Mayo and that the Federal Circuit found ineligible on multiple occasions.
In terms of the two-step Alice/Mayo analysis, Natera argued that the district court properly applied step one and relied on the express use of the word “detecting” in the claims, as well as Federal Circuit case law addressing similar “detecting” claims, to conclude that the claims were directed to a natural phenomenon. Natera also argued that the district court recognized that Alice step one can overlap with step two.
The Federal Circuit agreed with Natera, finding that the asserted claims were directed to detecting the natural phenomena of an organ donor’s cfDNA in the blood of a transplant recipient and the correlation between elevated levels of that cfDNA and organ transplant rejection. The Court agreed that the claims recited performing such detection using collection and measurement techniques that the specification admitted were conventional and could be performed using existing technology without modification. The Court deemed the claims indistinguishable from other diagnostic method claims that the Supreme Court found ineligible in Mayo.
The Federal Circuit found no error in the district court’s application of Alice/Mayo step one or in its reliance on case law finding similar “detecting” claims to be directed to a natural phenomenon, consistent with claims discussed in the 2015 Federal Circuit decision in Illumina v. Ariosa Diagnostics (relating also to cfDNA detection). The Court felt that the claims were “equally as ineligible” and “boil[ed] down to” collecting a bodily sample, analyzing the cfDNA using conventional techniques (including PCR), identifying naturally occurring DNA from the donor organ, and using the natural correlation between heightened cfDNA levels and transplant health to identify a potential rejection. The Court deemed none of this as inventive.
The Federal Circuit further noted that there can be overlap between Alice/Mayo steps one and two, at least in terms of the conventionality inquiry (“we have repeatedly analyzed conventionality at step one as well.”)
Practice Note: Be extremely careful about specification descriptions of the background and state of the art and categorizations or suggestions of what methods and techniques are known and can be applied to claimed methods.