It has been ten years since the US Supreme Court issued its decision in Mayo v. Prometheus. In that unanimous decision, the Court invalidated and made ineligible patent claims directed to medical diagnostic methods. It is tempting to use this anniversary as an opportunity to restate the myriad of legal flaws in a decision that has measurably damaged the biotechnology investment landscape. However, while such a rhetorical take-down might earn me some words of agreement or encouragement from like-minded readers, it would be like a fire that provides heat but no light. So instead, and with a ten-year perspective of patenting (or trying to patent) medical diagnostic methods in a post-Mayo world, here is a view of where we are and where we might be going.
Before we discuss the present, a few words about the past. Before Mayo, a medical diagnostic patent claim could be distilled to two main components: (1) Detecting a biomarker, which most commonly would be a specific gene sequence or a circulating biomolecule; and (2) Correlating the presence or absence of that biomarker with an associated disease or condition. One basis for patentability of such claims can be found in the basic requirements of patentable inventions set out in 35 U.S.C §101: "Whoever invents or discovers any new and useful process. . . may obtain a patent therefor" (emphasis added). However, the Court in Mayo held that the association between a biomarker and a condition is not a patentable discovery, but rather is no more than an unpatentable "law of nature," similar to Einstein's Theory of Relativity. To be patentable, Mayo required that a claim deemed to be directed to a law of nature must have some additional "inventive concept" that is "significantly more" than just the law of nature.
Unhelpfully, the Court in Mayo did not specify what constitutes a sufficient inventive concept to transform an unpatentable law of nature into a patentable invention. You might think, "It's been ten years, surely the combination of the USPTO and the courts, with guiding adjustments from the US Supreme Court in further cases, would have ironed out the details!" Think again. Ten years later, there is still no consensus. After Mayo, I had multiple interviews with US patent examiners in which we both expressed frustration and dismay at the lack of real guidance. Worse still, for many years, what "worked" for one patent examiner did not for another, and constantly changing guidance from the USPTO has been no more than reactive to disparate decisions in the courts.
The legal uncertainty that I experienced at ground-level has been further reflected in the variety of legal opinion expressed by the judges of the Court of Appeals for the Federal Circuit (CAFC), which has exclusive jurisdiction over patent appeals. Exhibit A for this was the 2019 dismissal of a petition for en banc rehearing of the diagnostic method case in Athena v. Mayo. In that case, the CAFC issued a short Order dismissing the petition, which was accompanied by eight separate opinions from the CAFC judges, four concurring in the denial of the petition and four dissenting in the denial of the petition. Despite this and other "cries for help" from the judiciary, the Supreme Court neither agreed to hear the Athena case, nor any other recent case presenting a question relating to patent eligibility.
So, in 2022, is it possible to obtain a medical diagnostic patent claim in the United States? The answer is a resounding (and unsatisfying) "sort of." Under current USPTO practice, and in view of the CAFC decision in Vanda v. West-Ward, it is possible to obtain a claim that recites a diagnostic method, so long as it is within the context of a method of treatment. How does this work? By adding a treatment step that is directed by the conclusion of the diagnosis steps. Conceptually, the connection of the diagnostic and treatment steps is an "inventive concept" because without the diagnosis, there would be no need to provide the claimed treatment. However, the treatment must be part of the claim. If your reaction to this is, "Wait a second, that isn't a diagnostic method claim!" You are correct, it's not, but under the current legal practice this is usually the best we can do. Any patent application that describes medical diagnostic methods (which remain patent-eligible in much of the world), should also include detailed description of treatments that should be administered following the diagnosis steps.
Is there any hope in the future for diagnostic method claims that do not require a treatment step? I think so, but not at the US Supreme Court. As it said in Mayo: "we must hesitate before departing from established general legal rules lest a new protective rule that seems to suit the needs of one field produce unforeseen results in another. And we must recognize the role of Congress in crafting more finely tailored rules where necessary. . . We need not determine here whether, from a policy perspective, increased protection for discoveries of diagnostic laws of nature is desirable." To put it a little bluntly, the Court had no issue breaking the system, but it is up to Congress to clean up the mess.
It will come as no surprise that no elected official is likely to win or lose an election based on their position when it comes to eligibility of medical diagnostic methods. However, despite it not being a front-page issue, the good news is that some officials in the US Congress are interested anyway. In 2019, following proposed legislation to revise the patent eligibility statute, the Senate Judiciary Committee held three days of hearings to examine the state of patent eligibility. While the proposed legislation did not move forward at the time, congressional pressure has recently induced the USPTO to begin a new pilot program in which patent applicants can defer a response to patent eligibility issues prior to responding to the other standard issues of novelty, non-obviousness, descriptive support, and claim language. This pilot program benefits applicants, because too often subject matter eligibility rejections become improperly tangled with issues of non-obviousness, and the pilot program will allow an applicant to demonstrate the "inventive concept" underlying a claim separately from subject matter eligibility. Secondly, and perhaps just as importantly, by deferring the patent eligibility issue until all other issues are resolved, the USPTO, and by extension Congress, will be able to clearly determine the number of patent applications that are patentable but for the issue of patent eligibility. Such data would undoubtedly be helpful in moving the legislative process forward.
Ten years after Mayo, obtaining a non-treatment-connected diagnostic method patent claim remains a challenge in the US. However, I think change is coming, even if it will take time. In the meantime, best practice, as in so many things, is to be flexible! Patent applications should include a variety of possibilities (i.e., with and without a treatment step) to enable a variety of claims, and so that when the legislation moves forward (and it will), we will be ready for it.
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