A recent significant decision by the US Supreme Court struck down the validity of a patented treatment for a medical disorder as being nothing more than a "conventional" application of a law of nature, which is ineligible for patenting.

The decision is likely to affect patents relating to life sciences, biotechnology and other technologies.

The patents at issue use thiopurine drugs to treat autoimmune diseases such as Crohn's disease and ulcerative colitis.

The patents purported to enable doctors to determine whether a given dose is excessive and potentially harmful for a particular patient, or deficient and likely to be ineffective.

Prometheus Laboratories, the exclusive licensee of the patents in the suit, had sued Mayo Clinic Rochester and Mayo Collaborative Services for infringement of the patents.

The issue on appeal before the supreme court was whether the process claimed in the patents qualified as patent-eligible subject matter.

In addition to a step for administering a thiopurine drug to a patient, the court characterized the process in the patents as having essentially the following three steps: Measuring a metabolite level; using a particular law of nature - that is, a relation defining consequences of how thiopurine compounds are metabolized by the human body - to calculate toxicity/inefficacy limits; and reconsidering the drug dosage in light of the natural law.

The court reiterated its long-held precedent that laws of nature, natural phenomena and abstract ideas in themselves are not patentable, yet some natural laws, phenomena or ideas sometimes can be patentable as defined by Section 101 of the patent law.

Looking to precedents, the court considered two prior cases that reached opposite conclusions.

One involved a mathematical formula for molding uncured rubber that was found patent-eligible because the process steps added concepts that were not obvious, already in use or purely conventional - transforming the process into an inventive application of the formula.

The other prior case involved a method for adjusting alarm limits using a mathematical algorithm, which was found not patent-eligible because the steps all involved well-known concepts with no inventive concept in the application of the algorithm.

Characterizing the process of patent claims in the Mayo case as "weaker than the (patent-eligible) claim" and "no stronger than the (unpatentable) claim" in the denied case, the court ruled that the process steps added nothing beyond the law of nature except for "well-understood, routine, conventional activity, previously engaged in by those in the field".

In particular, the court held that the "administering" step refers merely to a pre-existing audience, namely, doctors who treat patients with thiopurine drugs, and cannot render the claimed process patentable by virtue of limiting use to a particular environment.

Next, the court ruled that the measuring step merely informs doctors to "engage in well-understood, routine, conventional activity previously engaged in by scientistsin the field."

Additionally, the court found that the step of reconsidering the drug dosage "simply tells a doctor about the relevant natural laws, at most adding a suggestion that he should take those laws into account when treating his patient".

According to the court, even in combination, the process amounts to nothing more than an instruction to doctors to apply natural laws during treatment, so it was found to be unpatentable.

Notably, the court declined to decide whether it would have reached a different conclusion had the claimed steps been deemed "less conventional" and also rejected an argument that virtually any step beyond a law of nature itself should qualify for Section 101 of the patent law because other laws screen for patentability requirements such as novelty, non-obviousness and sufficiency of description.

According to the court, such an approach to Section 101 would render the "law of nature" exception a "dead letter" and would create greater legal uncertainty.

The Mayo decision may have a significant impact on patents in the life sciences and biotechnology industries, particularly for technologies involving diagnostic tests and treatments that, like those involved in Mayo, depend on naturally occurring relationships in the human body.

Moreover, given the court's emphasis on prior cases involving mathematical formulas and the like, Mayo's impact might extend to other technologies as well, such as business methods and computer technologies. The full effects of the Mayo decision remain to be seen.

Authors Frank A. DeLucia is a partner of Fitzpatrick Cella, Harper & Scinto and Agatha H. Liu is an associate of the US law firm.

(Source: China Daily)