USPTO releases new guidelines for determining patent eligibility of nature-based inventions

USPTO releases new guidelines for determining patent eligibility of nature-based inventions

USPTO releases new guidelines for determining patent eligibility of nature-based inventions

Over the past several years the United States Supreme Court has handed down numerous decisions related to patent subject matter eligibility, i.e. whether certain subject matter should be eligible for patent protection.  These decisions appear, at least in part, to have been made in response to a growing concern that patents were “tying up” laws of nature and natural phenomena and preventing others from using or applying them.  These decisions have had a significant impact on what types of claims may be granted patent protection by the USPTO.  In particular, the patent eligibility of diagnostic methods, personalized medicine, and chemical or biological products, which were once routinely the subject of patents, have come under intense scrutiny.

In the wake of the recent Supreme Court decisions and the resultant uncertainty over patentability on the part of patent examiners, applicants and attorneys alike, the United States Patent and Trademarks Office (USPTO) has released updated guidelines for determining subject matter eligibility, with associated training examples.  The guidelines are particularly relevant to claims directed to nature-based inventions (e.g. biotech, chemical, pharmaceutical and diagnostic inventions) as well as computer-implemented inventions (e.g. software, business methods, etc.).  We focus here on the guidelines as they relate to nature-based inventions.

Is the claim directed to a law of nature or natural phenomenon?

Under United States law, natural phenomena and laws of nature have long been held to be unpatentable.  A claim is considered to be directed to a natural phenomenon or law of nature if it recites a nature-based product, such as DNA, a protein or a chemical, that does not have markedly different characteristics compared to that which occurs in nature, or if it recites a naturally-occurring principle.  

Streamlined eligibility analysis, including for methods of treatment

The USPTO guidelines make it clear that claims reciting a natural phenomenon or law of nature should still be considered patent-eligible if it is apparent that the claims do not seek to “tie up” the natural phenomenon or law of nature.  For example, an artificial hip prosthesis coated with a naturally-occurring mineral is not an attempt to “tie-up” the mineral and is not directed to a natural phenomenon or law of nature even though it recites one.  Using this analysis the USPTO has indicated that, generally speaking, methods of treatment will be patent-eligible because they are typically directed to the process of practically applying a nature-based product and do not seek to “tie-up” the nature-based product itself.

Does the claim amount to more that a law of nature or natural phenomenon?

If the claim is directed to a law of nature or natural phenomenon, then it will still satisfy the patent-eligibility requirement if it contains additional elements or a combination of elements that result in the claim as a whole amounting to significantly more than the law or natural phenomenon itself.  Examples of limitations that can satisfy this “significantly more” test include those that recite something other than what is well-understood, routine and conventional in the field, or that add an unconventional step that confines the claim to a particular useful application.  Conversely, appending well-understood, routine and conventional activities previously known in the field, or adding an activity that is not central to the purpose of the invention (e.g. adding a data gathering step to a method when all applications of the method would require such a step and it would not impose a further meaningful limit to the claim), is not sufficient to make a claim amount to significantly more than a law of nature or natural phenomenon.

“Markedly different” nature-based products

To determine whether a nature-based product is markedly different from its naturally-occurring counterpart, the following characteristics are taken into consideration:

  • biological or pharmacological functions or activities;
  • chemical and physical properties;
  • phenotype, including functional and structural characteristics; and
  • structure and form, whether chemical, genetic or physical.

The USPTO has indicated that the following differences are sufficient to satisfy the “markedly different” test:

Proteins and nucleic acids

  • single or multiple amino acid or nucleotide differences, regardless of whether it results in a functional change.
  • heterologous nucleic acids or amino acids, or labels.
  • changes in glycosylation as a result of recombinant expression.
  • changes in crystal structure.


  • different structures, such as one or more different chemical groups, even if the change in structure does not result in a functional change.
  • changes in solubility, such as by formulation with a  solubilizing agent.


  • antibodies are patentable provided the antibody does not exist in nature, and the onus is on the USPTO to demonstrate such an existence.    
  • chimeric, humanized and other variant forms of antibodies.


  • phenotypic differences arising from human manipulation, such as genetic engineering or culture methods.


  • mixtures of bacterial species that display different biological or functional characteristics as a mixture compared to as individual species.
  • as with antibodies, the onus is on the USPTO to demonstrate the existence of a particular mixture of bacteria – the mere possibility that it might exist in nature is not sufficient for a rejection.

Naturally-occurring principles and patentability of diagnostic methods

As recently decided by the Supreme Court in Mayo v Prometheus, correlations based on the metabolism of a compound by the body are deemed naturally-occurring principles.  Relying on this decision, the USPTO has since routinely concluded that the correlation between the presence or level of a protein or nucleic acid in the body and a disease state is also a naturally-occurring principle.  As a result, diagnostic methods and personalized medicine methods are now generally considered by the USPTO to be directed to natural phenomena or laws of nature and are hence patent-ineligible.

Unfortunately, the USPTO guidelines do not provide any further guidance by way of commentary or training examples on what might make a diagnostic method claim amount to “significantly more” than the naturally-occurring principle upon which it relies.  Based on our recent experience, unless the method includes the use of a new diagnostic reagent or assay, generally speaking the USPTO considers most additional steps in a broad diagnostic method to be well-understood, routine or conventional, and the method is rejected as being directed to patent-ineligible subject matter.  

Where to from here?

While forming the basis on which US patent examiners will assess the question of patent eligible subject matter, one should bear in mind that the new USPTO guidelines are not legally binding and may be modified or changed as new judicial decisions are handed down.  In addition, any final adverse decision by the USPTO can be appealed.  This area of law is rapidly changing and it not yet clear how broadly the US Courts will apply the recent decisions in Mayo v Prometheus and others.  

Despite the somewhat negative treatment that claims to diagnostic methods or natural products are currently receiving at the USPTO, applicants working in these areas should not assume that their inventions are no longer patentable.  The complexity of the law and, in some cases, lack of clear guidance from the Courts and USPTO means that such inventions should be assessed on a case-by-case basis.  Certain strategies can also be adopted to increase the likelihood that claims can be crafted satisfying the patent-eligibility requirements and affording commercially relevant protection.  We would encourage clients to discuss these with us.