CASE BRIEF: Mayo Collaborative Services v. Prometheus Laboratories, Inc.

 

Citation	566 U.S. 66 (2012)
Docket no.	10-1150
Granted on	June 20, 2011
Presented on	December 7, 2011
Decided on	March 20, 2012

Introduction 

The case of Mayo Collaborative Services v. Prometheus Laboratories centered on patents related to the optimization of thiopurine drug treatment for autoimmune diseases. At its core, the case addressed a fundamental question in patent law: when does the application of a natural law become patent-eligible?

The background of the case involved two patents (No. 6,355,623 and No. 6,680,302) owned by Prometheus Laboratories that covered a method for determining the optimal dosage of thiopurine drugs. These drugs, used to treat autoimmune diseases, are metabolized differently by different patients, making it challenging for doctors to determine the right dosage. The patents described a process that involved:

1. Administering the thiopurine drug to a patient
2. Measuring the levels of certain metabolites in the patient’s blood
3. Adjusting the dosage based on specific correlations between metabolite levels and drug efficacy/toxicity

The controversy arose when Mayo Clinic, which had previously been purchasing and using Prometheus’s diagnostic tests, announced in 2004 that it would begin using its own test with slightly different metabolite thresholds. Prometheus responded by filing a patent infringement lawsuit.

The case’s significance lies in how it addressed the fundamental tension between:

– The need to protect genuine innovations in medical treatment

– The principle that laws of nature (such as the natural correlation between metabolite levels and drug efficacy) should remain free for all to use

The Supreme Court had to determine whether the patents added enough to the natural correlations they described to qualify as patent-eligible processes, or whether they simply claimed natural laws with instructions to “apply it” – a distinction that would prove crucial for future patent applications in the medical and biotechnology fields.

This case would go on to establish important precedent about what constitutes patent-eligible subject matter under Section 101 of the Patent Act, particularly in the context of diagnostic methods and medical treatments that rely on natural phenomena or laws of nature.

Facts of the case 

The facts of Mayo v. Prometheus centered around the medical use of thiopurine drugs and their metabolization in patients with autoimmune diseases. Thiopurine, when ingested by patients, is metabolized in the body, forming metabolites in the bloodstream. However, this metabolization process varies significantly among individuals, creating a clinical challenge where the same dose could affect different patients in vastly different ways. Some patients might receive too high a dose, risking harmful side effects, while others might receive too low a dose, rendering the treatment ineffective.

Prior to the patents in question, scientists had established a general correlation between metabolite levels in a patient’s blood and the likelihood of the thiopurine dosage being harmful or ineffective. However, the precise correlations between these metabolite levels and clinical outcomes were not well understood by practitioners in the field. Prometheus Laboratories held two U.S. patents (No. 6,355,623 and No. 6,680,302), filed with a priority date of September 24, 1998, which claimed to have identified these correlations with greater precision. These patents covered a specific method for optimizing therapeutic efficacy, which included processes for drug administration, metabolite measurement, and dosage adjustment based on the measured levels.

As the exclusive licensee of these patents, Prometheus Laboratories commercialized diagnostic tests incorporating these patented processes. Mayo Clinic Rochester and Mayo Collaborative Services (Mayo) initially purchased and utilized these tests from Prometheus. However, the relationship changed in 2004 when Mayo announced its intention to begin producing and selling its own diagnostic test. Mayo’s test was similar but used slightly higher metabolite levels as thresholds for determining toxicity. This announcement prompted Prometheus to file a patent infringement lawsuit against Mayo, initiating the legal battle that would eventually reach the Supreme Court.

The case’s journey through the courts was complex. Initially, the District Court ruled against Prometheus, finding that the patents effectively claimed natural laws or phenomena – specifically, the correlations between thiopurine-metabolite levels and drug toxicity/efficacy – making them unpatentable. The Federal Circuit reversed this decision in 2009, emphasizing that the claimed processes included specific steps beyond just the natural correlations. After the Supreme Court’s initial remand for reconsideration, the Federal Circuit reaffirmed its original decision, leading to Mayo’s second petition for certiorari, which the Supreme Court granted. This complex procedural history underscores the challenging nature of determining patent eligibility for processes that involve both natural phenomena and human intervention.

Arguments by the parties 

Here are the key arguments presented by both parties in the Mayo v. Prometheus case:

Arguments by Prometheus Laboratories:

1. Patent Eligibility Based on Specificity: Prometheus argued that their patents should be upheld because the laws of nature they embodied were narrow and specific, not broad general principles. They claimed the precise correlations they identified between metabolite levels and drug efficacy were unique and deserved protection.
2. Process Integration: They contended that their patents didn’t just describe natural correlations but integrated them into a specific process that included administering drugs, measuring metabolites, and adjusting dosages.
3. Innovation Protection: Prometheus argued that denying patents for such applications would discourage innovation in medical diagnostics and treatment methods.

Arguments by Mayo Clinic:

1. Natural Law Application: Mayo argued that the patents merely described natural correlations between metabolite levels and drug effects, with basic instructions to “apply it” – something the Supreme Court had previously ruled insufficient for patent protection.
2. Conventional Steps: They contended that the additional steps in the process (administering the drug, measuring levels, adjusting dosage) were routine, conventional activities that doctors were already performing.
3. Innovation Impediment: Mayo argued that allowing such patents would impede rather than promote innovation by monopolizing basic scientific relationships.

The U.S. Government’s Position (as amicus curiae):

The government took an interesting middle position, arguing that:

1. Any step beyond merely stating a law of nature should potentially transform it into a patentable application.
2. Other statutory provisions (novelty, non-obviousness, and clear description requirements) could adequately screen patent applications.
3. The specific claims in Prometheus’s patents likely failed for lack of novelty, rather than patent eligibility.

The Supreme Court ultimately rejected both Prometheus’s narrow approach and the government’s broad approach, finding that allowing patents on applications of natural laws that involve only conventional, routine steps would make the law of nature exception meaningless. They were particularly concerned that relying solely on other statutory provisions for screening, as suggested by the government, would create greater legal uncertainty.

Judgement of the case 

The Supreme Court’s judgment in Mayo v. Prometheus was a landmark decision that significantly impacted patent eligibility, particularly for medical diagnostic methods. Here’s a detailed analysis of the judgment:

Core Decision:

The Supreme Court unanimously ruled that Prometheus’s patents were invalid because they effectively claimed laws of nature. The Court held that an application of a natural law is not patentable if the additional steps only involve “well-understood, routine, conventional activity” previously used by researchers in the field.

Key Elements of the Court’s Analysis:

1. Examination of Patent Claims:

The Court broke down Prometheus’s patent claims into three steps:

– The “administering” step

– The “determining” step

– The “wherein” step (indicating need to adjust dosage)

The Court found that none of these eps, individually or in combination, added enough to transform the natural law into a patent-eligible application.

2. Specific Findings on Each Step:

– The “administering” step merely identified the target audience (doctors using thiopurine drugs)

– The “determining” step only told doctors to use any known testing method

– The final step simply informed doctors about the natural law and suggested they consider it

3. Legal Framework Established:

The Court emphasized that to be patent-eligible, an application of a natural law must include elements or steps that amount to significantly more than the natural law itself. Simply appending conventional steps to a natural law doesn’t make it patentable.

4. Rejection of Alternative Approaches:

– Rejected Prometheus’s argument about narrow, specific natural laws deserving protection

– Dismissed the government’s suggestion that any steps beyond stating a natural law should make it patentable

– Emphasized that courts aren’t well-suited to distinguish between different types of natural laws

5. Policy Considerations:

The Court expressed concern that allowing such patents would:

– Risk tying up future use of natural laws

– Inhibit future innovation rather than promote it

– Create a monopoly over the basic tools of scientific research

 

Impact of the Decision:

1. Established a stricter test for patent eligibility of processes involving natural laws
2. Led to immediate changes in USPTO guidelines
3. Created a three-step inquiry for patent eligibility:

   – Does the invention address a process?

   – Does it involve contentious subject matter (laws of nature)?

   – Are there additional elements that integrate the natural principle practically?

 

The judgment has had lasting implications for patent law, particularly in medical diagnostics and biotechnology, making it more challenging to patent diagnostic methods that rely on natural correlations, even when combined with conventional medical procedures.

 

This decision continues to influence patent examination and litigation, especially in cases involving the intersection of natural phenomena and medical innovations. It emphasizes the need for genuine innovation beyond merely applying known scientific principles through conventional methods.