Mayo v. Prometheus

The following is an Austin, Texas patent attorney’s overview of Mayo v. Prometheus, and learning lessons for patent attorneys.


Claim 1 of Prometheus’ 6,355,623 patent which is in question in this case, recited:

A method of optimizing therapeutic efficacy for treatment of an immune-mediated gastrointestinal disorder, comprising:

(a) administering a drug providing 6-thioguanine to a subject having said immune-mediated gastrointesti­nal disorder; and

(b) determining the level of 6-thioguanine in said subject having said immune-mediated gastrointesti­nal disorder,

wherein the level of 6-thioguanine less than about 230 pmol per 8×108 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 8×108 red blood cells indicates a need to decrease the amount of said drug subsequently ad­ ministered to said subject.

In this case Prometheus sued Mayo contending that Mayo infringed Prometheus’ ‘623 patent including the above recited claim.

Initially, the district court held that Mayo did not infringe the ‘623 patent because the ‘623 claims are directed towards natural laws or natural phenomena which are not patentable subject matter under §101.

The Federal circuit reversed the district court’s ruling under the “machine or transformation” test as laid out in Bilski because by applying Prometheus’ method of applying a drug, blood cells are transformed or modified.

The Supreme Court reversed the Federal circuits hold concluding that 1) natural laws are not patentable subject matter, and 2) claimed processes are not patentable unless they have additional features that provide practical assurance rather than being merely correlated. The court reasoned that doctors had been using the method of administrating drugs long before the ‘623 patent had been granted, and that by performing the method of the ‘623 patent was not sufficient to transform an unpatentable law of nature into a patent-eligible application of such a law. Citing Bilski, the court stated that simply appending obvious/general steps to laws of nature and abstract ideas cannot make those laws, phenomena, and ideas patentable.



1)     You cannot claim a method that is already known in the art, or that is similar to what is known in that art. For mobile applications/software, it will be interesting if the Supreme Court would uphold a method claim using software in a new way, if there are no additional features to the software components that make the software easier to use. For example, for patents that use voice instead of a touchscreen or mouse, it appears that this court would hold those processes to be unpatentable. Therefore, when drafting a claim make sure you use at least some sort of tangible item, I believe that in Prometheus if they had tied their “determining” step to a specific apparatus or measuring device they would have had patentable subject matter.

2)     The federal circuit held that transformation of the human body or blood is substantial enough to meet the “transformation or machine test” laid out in Bilski. For software claims that produce a display, I wonder if the impression stored on a retina would be enough to “transform” the eye. I think that answer is “probably not” because the image is stored so briefly on a retina, but it would be interesting to see going forward with new “3-D technology” as well as “virtual reality” technologies. Each of these technologies uses phenomena of the human body to create a secondary result, such as viewing projections from a 2-D surface.  These phenomena of the human body, by themselves are not patentable, and it appears the changes to your body caused by these phenomena will not satisfy the “machine or transform test.”

3)     However, as a patent attorney I believe the main takeaway from this case is that if you are going to patent a method of performing steps, make sure to include tangible mediums to at least one (if not all) of the steps.

By | 2012-10-28T23:07:27+00:00 October 28th, 2012|Blog, Patent Attorney Takeaways|Comments Off on Mayo v. Prometheus