On March 4 2014 the US Patent and Trademark Office (USPTO) issued its Guidance for Determining Subject Matter Eligibility of Claims Reciting or Involving Law of Nature, Natural Phenomena and Natural Products, to assist patent examiners in assessing whether claims cover subject matter that is eligible for patentability. Over the past couple of years the Supreme Court has addressed this issue in a number of cases, including Myriad (natural products exception) and Prometheus (laws of nature exception). The guidance provides a three-question test, which culminates in the query of whether, if the subject matter of the claim falls into one of the four judicial exceptions to patentability (abstract ideas, laws of nature/natural principles, natural phenomena and natural products), the subject matter is nonetheless “significantly different” and therefore patent eligible. The guidance goes on to provide guidelines as to how 'significantly different' should be determined and sets forth a series of factors which must be assessed and balanced to make that determination. The USPTO also provides a series of examples to illustrate how the balancing test should be applied.

The implementation of these guidelines is expected to result in an increase in Section 101 rejections, some of which may not otherwise have been raised. For example, in assessing whether the subject matter of a claim covers a product of nature, the USPTO appears to consider each claimed element by itself, and the presence of a product of nature as only one of the claimed elements could be the basis for a rejection if the examiner considers that the factors overall weigh in favour of ineligibility. Therefore, going forward, patent prosecution – in particular, drafting of new applications – should take these guidelines into account, and while circumventing such rejections where possible  should also be aggressive in rebutting Section 101 rejections where the case law does not support them.