Patent law typically provides protections for people who invent or discover new processes. However, the Court makes exceptions to this rule by providing exceptions for those who try and patent "laws of nature." One court case involving Mayo Collaborative Services v. Prometheus Laboratories, Inc. explores the limits of patentable inventions and processes and has severe implications for pending and future Federal Circuit cases. Let's discuss what happened in this case.


The Mayo Foundation for Medical Education and Research, affiliated with a nonprofit academic medical center called the Mayo Clinic, operates a for-profit testing lab called Mayo Collaborative Services.

At the testing lab, Mayo Collaborative Services bought medical tests from Prometheus Laboratories, Inc. to help improve patient outcomes will administering medications.

Essentially, the treatment of autoimmune diseases requires the use of thiopurine drugs. Yet, there's a challenge with administering thiopurines. Every individual's body metabolizes this class of drugs differently. Therefore, safe, and effective administration of thiopurines requires doctors to run diagnostic tests to ensure patients are prescribed the correct dose. Too high of a dose leads to adverse side effects, while too low and the thiopurines become ineffective at treating disease.

Scientists at the Hospital Sainte-Justine in Montreal were the first to discover the threshold of efficacy while treating some autoimmune diseases by testing a patient's blood. After making this discovery, these scientists filed a patent on methods that use the threshold level to determine the correct dosage for patients.

Prometheus Laboratories, a corporation owned by Nestlé, creates diagnostic testing kits and operates a testing lab to obtain information about a patient that helps diagnose and treat disease. They were the party to license two patents from the Hospital Sainte-Justine to build tests that help doctors discover the correct medication dosage.

Mayo Collaborative Services used diagnostic kits from Prometheus Laboratories until 2004. Afterward, Mayo created its diagnostic equipment, which it planned to operate within its testing lab, while also selling it to other medical centers. After announcing that Mayo would produce and sell their diagnostic kits to identify the proper dosage of thiopurines for fighting autoimmune disease, Prometheus sued Mayo for patent infringement.

The case went to District Court, the Federal Circuit Court twice, and finally, the Supreme Court. The District Court found that to use the test required three steps:

  1. A doctor must administer a thiopurine-containing drug to a patient.
  2. The medical professional performs a test to determine the metabolite levels in the patient's blood.
  3. From testing, the doctor determines whether there should be a change in the dosage of the thiopurine medications.

During the case, the third point became a point of dispute between both parties. Although Prometheus felt that the whole process was patentable, the Court decided otherwise, believing that the inventors were observing the relationship of a natural process rather than creating a new process itself. Therefore, Prometheus held patents to a "law of nature," which shouldn't be patent-eligible.

In the higher courts, there was much back and forth between both corporations about the earlier rulings. However, in 2012, there was a unanimous decision from the Supreme Court that supported the initial findings of the District Court. The Justice argued that companies could not patent a product that identifies the connection between naturally produced chemicals within the body and the efficacy of a medication.


This ruling brought support and opposition to the Supreme Court by those in the biotech industry, law schools, and medical associations. After one day of the verdict, the United States Patent and Trademark Office issued a memorandum that explained how to determine whether new patents were valid per the Supreme Court ruling. 


Disclaimer: The views and opinions expressed throughout this blog are the views and opinions of the individual author(s) and/or contributor(s) and do not necessarily reflect the views and opinions of our firm, CIONCA IP Law. P.C. 

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  • CIONCA IP TEAM (SE)8/13/2021 4:57:49 PM

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Marin Cionca | Founder of CIONCA IP

Marin Cionca, Esq.

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About CIONCA® IP Law firm: We are an Irvine, Orange County, California based boutique intellectual property law firm with a focus on patent and trademark application, prosecution, opinion, licensing and IP enforcement services, including IP litigation, offering its IP services, other than IP litigation, primarily at flat fee rates. We serve local OC (Orange County) clients, as well as clients from the Los Angeles, San Diego and Riverside Counties and clients throughout the state of California, the United States and also international clients, such as EU clients.

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