Medical Process Patents Declared Invalid

Medical process patents are important for personalized medicine because they can protect certain types of innovations such as therapeutic treatments and diagnostic and genetic testing methods. Such patents, however, face uncertainty as an increasing number of validity challenges are being brought under section 101 of the Patent Act.¹ The standard for determining patent-eligibility has changed since the 1980s and the U. S. Supreme Court has recently been taking a more restrictive approach to granting patent protection. In the most recent case — Prometheus Laboratories, Inc. v. Mayo Collaborative Services² — a unanimous Court held that diagnostic testing method claims that represent conventional applications of the laws of nature were invalid under section 101.

Background

To qualify for patent protection, an invention must first satisfy several criteria, including novelty, usefulness, and nonobviousness. As a general rule, anything under the sun that is created by man can qualify for patent protection. On the other hand, laws of nature, natural phenomena, abstract ideas, and mental processes cannot. At issue in Mayo was how this exception applies to medical diagnostic testing claims.

Denying patent coverage of natural correlations could stimulate genetic research, says Joanna T. Brougher, JD, MPH.

The claims at the center of the dispute involve the method of administering a drug to a patient — in this case, to treat autoimmune diseases — and then determining the level of metabolite in the patient’s body as a measure of the toxicity and efficacy of the dosages. Prometheus Laboratories, based in San Diego, developed and sold diagnostic tests based on those claims, and Mayo Clinic Rochester and Mayo Collaborative Services (Mayo) bought and used those tests. In 2004, however, Mayo stopped using Prometheus’s tests in favor of its own test, which employed higher metabolite levels to determine toxicity. Prometheus then sued Mayo for patent infringement.

The district court held that Mayo infringed Prometheus’s patents but ultimately found those patents to be invalid because they claimed protection for laws of nature. Specifically, the court found that the correlation between metabolite levels and the toxicity and efficacy of drug dosages are correlations that are found in nature.

On appeal, the federal circuit overruled the district court and upheld Prometheus’s claims in view of the “machine or transformation” test. According to the federal circuit, Prometheus’s claims satisfied the “transformation” prong of the machine or transformation test because (1) the human body is transformed during drug administration because “drugs do not pass through the body untouched,” and (2) in determining metabolite levels, “[s]ome form of manipulation … is necessary to extract the metabolites from a bodily sample and determine their concentration.”³ On remand, the federal circuit reaffirmed its decision, stating that Prometheus’s method “recite[s] specific treatment steps, not just the correlations themselves,” and “involve a particular application of the natural correlations: the treatment of a specific disease by administering specific drugs and measuring specific metabolites.”⁴

The Supreme Court’s Decision

Mayo filed a petition for certiorari, which was granted by the Supreme Court, and on March 20, 2012, the Supreme Court issued a decision in favor of Mayo.⁵ The court recognized “a process is not unpatentable simply because it contains a law of nature or a mathematical algorithm.”However, the court said, “to transform an un-patentable law of nature into a patent-eligible application of such a law, one must do more than simply state the law of nature while adding the words ‘apply it.’” Because Prometheus’s claims set forth laws of nature — namely, correlations between metabolites in the blood and efficacy and toxicity of a drug — the question before the Supreme Court was whether these claims “add enough to their statements of the correlations to allow the processes they describe to qualify as patent-eligible processes that apply the natural laws.”

In deciding whether the claims do more than simply describe natural correlations, the Supreme Court analyzed each step of the method patent as well as their combination. First, the court analyzed administration of the drug and found that it simply referred to the relevant audience, i.e., doctors treating patients. The next step, determining metabolite levels, only told doctors to determine the level of the relevant metabolites in the blood using any applicable process. The “wherein” step, moreover, only told the doctor about relevant natural laws and suggested that the doctor take those natural laws into consideration when treating patients. Finally, the court considered the steps as a combination and found that the combination “amounts to nothing significantly more than an instruction to doctors to apply the applicable laws when treating their patients.”

According to the Supreme Court, the three steps claimed by the patents consisted solely of “well-understood, routine, conventional activity already engaged in by the scientific community,” and “when viewed as a whole, add nothing significant beyond the sum of their parts taken separately.” Because Prometheus’s claims added nothing of value to the laws of nature, the Supreme Court found them insufficient to transform natural correlations into patentable subject matter.

In its decision, the Court stressed the importance of the laws of nature in excluding inventions from patentability. In particular, the Court refused to uphold claims to laws of nature even if those claims otherwise satisfied the “machine or transformation” test and even if those claims were narrowly and specifically tailored to that particular law of nature. Thus, the court upheld a clearly established prohibition against patenting laws of nature.

Impact of Mayo

The Supreme Court’s decision in Mayo has profound implications for innovations related to diagnostics and personalized medicine. Perhaps the most significant issue will be the manner in which future courts decide whether a claimed process does more than simply describe a natural correlation.

Two cases lurk in the wake of the Mayo decision. The first is Classen Immunotherapies, Inc. v. Biogen,⁶ which is directed to methods for determining an optimal immunization schedule based on comparing the observed incidence of immune-mediated disorders in treatment groups subjected to different vaccination schedules. Read broadly, such a claim could be infringed by any person who reviews relevant information. In view of Mayo, these claims may be invalidated as doing nothing more than simply describing a natural correlation.

The second case involves Myriad Genetics’s patents related to genetic diagnostic testing. While Myriad is better known for its patents covering the BRCA1 and BRCA2 genes, it also has patent claims covering their application in diagnostic tests. One claim is directed to comparing the BRCA1 germline sequence of a patient to the BRCA1 germline sequence in a control to see if there is an alteration in the patient’s gene. Based on the precedent set by Mayo, Myriad’s claims may be seen as doing no more than simply describing a natural correlation.

Conclusion

The Supreme Court’s decision may affect innovation in the development of diagnostics where patents are involved. On the other hand, denying patent coverage of natural correlations could stimulate genetic research — with fewer intellectual property hurdles, researchers might be able to conduct more extensive research that could then serve as the basis for developing new therapeutics. Patients and healthcare providers, accordingly, would have access to more affordable diagnostic tests and, therefore, more personalized treatment options.