[4] A 2017 study concluded, that the decision in Mayo promoted biotech businesses and non-profit institutions to "increase use of trade secrecy" rather than the more traditional patenting, with substantial detriment to the society.

The Supreme Court took claim 1 of the '623 patent as exemplary: A method of optimizing therapeutic efficacy for treatment of an immune-mediated gastrointestinal disorder, comprising:

wherein the level of 6-thioguanine less than about 230 pmol per 8x108 red blood cells indicates a need to increase the amount of said drug subsequently administered to said subject and wherein the level of 6-thioguanine greater than about 400 pmol per 8x108 red blood cells indicates a need to decrease the amount of said drug subsequently administered to said subject.Prometheus is the exclusive licensee of these patents and sells diagnostic kits based on them.

)[14] The debate between the two companies is based on a certain diagnostic test, specifically concerning the use of thiopurine drugs, which are used to treat autoimmune diseases.

The District Court characterized the claims as having three steps: (1) administering the drug to a subject, (2) determining metabolite levels, and (3) being warned that an adjustment in dosage may be required.

The decision said: [I]t is inappropriate to determine the patent eligibility of a claim as a whole based on whether selected limitations constitute patent-eligible subject matter.

[20] The Supreme Court's Bilski decision made the machine-or-transformation test less absolute, calling it only an "important clue" to patentability.

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.

Those opposed to it found the reasoning poor, considered the decision to be destabilizing of patent law, and expressed concern about long-term effects on medicine.

Gene Quinn, a well-known pro-patent spokesman, blogging in IP Watchdog, stated one view of the decision: "The sky is falling!

It took almost 10 years to overrule Gottschalk v. Benson, so we are likely in for a decade of work to moderate the nonsense [Mayo] thrust upon the industry this morning.

And the Court seems equally ready to be influenced by the consumers of innovation, such as amicus the American Medical Association, who understandably wish to have the maximum freedom to have their patients benefit from new technology (and the minimum interference from patent holders who would reduce their opportunities to profit therefrom).

[27]Hans Sauer, an attorney for the biotech industry trade group, BIO, said, "We are troubled that the Court's opinion fails to appropriately recognize the importance of personalized medicine, and of the research and investment incentives needed to develop new individualized therapies for untreated diseases.

"[4] On the other hand, those in favor of the decision found it "a very high quality piece of legal craftsmanship" that "may well be the Supreme Court's finest work in the patent-eligibility field.

"[31] In the same vein, this commentator praised the decision for reaffirming earlier precedents such as O'Reilly v. Morse and Neilson v. Harford, which the lower court in the Mayo case had ignored or seemingly misunderstood.

A business-oriented commentator viewed the decision as seeking to strike a balance between competing policy considerations: While the collective groans of patent professionals the world over are hard to ignore after the decision in Prometheus, it was a necessary evil to safeguard against the likely potential for financial posturing of companies with exclusive rights over processes of the human body.

Ultimately, the conclusion in Prometheus is premised upon the public policy consideration that certain types of medical and diagnostic findings should not be afforded patent protection, as the need for unencumbered access to critical scientific data and study in the medical community overwhelms any alleged monetary disincentive suffered by the patent applicant.

The Court recognized that patent protection should not serve as a stumbling block for continued scientific innovation and improvement in medical treatment methodologies.

The US Supreme Court dismissed its own writ of certiorari for LabCorp v. Metabolite, Inc. as improperly granted, but the minority opinion in that case suggested a test, which was eventually adopted in Mayo v. Prometeus.

[35] Soon after "Mayo" (in 2014) the Supreme Court decided another patentable subject matter case in Alice Corp. v. CLS Bank International.

In June 2020 the Office issued new guidelines on subject matter eligibility, which implement Mayo/Alice decisions and were incorporated into the MPEP, particularly in Sections 2103 through 2106.07(c).