Divergent patent pathways
The preamble of the Patent Cooperation Treaty (PCT) states the desire of the contracting states “to simplify and render more economical the obtaining of protection for inventions where protection is sought in several countries”.
This is done by filing one application that covers all contracting states. PCT filings therefore confer an enormous simplification for worldwide patent prosecution—in particular, requiring the filing of only a single initial application and allowing cost decisions to be postponed significantly. Many smaller biotechnology companies, often struggling with funding, have taken advantage of this system, which allows limited resources to be allocated more effectively.
From our experience, the key jurisdictions where patents are eventually pursued are nearly always multiple contracting states of the European Patent Convention (EPC) and the US, ie, prosecution before the European Patent Office (EPO) and the US Patent and Trademark Office (USPTO).
However, it has appeared that the standards applied by the competent US courts and the EPO’s boards of appeal regarding patentable subject matter in life sciences have diverged to such an extent that the strategy of filing a single PCT application for regional or national phase entry in both these jurisdictions may no longer be the best option. We provide some examples.
One decision that caused major concerns for those engaged in the patenting of diagnostic tools was Mayo v Prometheus, decided by the US Supreme Court in March 2012. In its decision, the court embarked on assessing patentability of claims protecting a method of optimising therapeutic efficacy for the treatment of an immune-mediated gastrointestinal disorder.
The method comprised the steps of administering a drug to a subject and determining the amount of a metabolite in the blood. The claim stated that an amount of that metabolite below a certain threshold value “indicates a need” to increase the dose of the drug in subsequent administrations (since the treatment was ineffective).
On the other hand, the claim stated that if the amount of the metabolite was increased in the blood beyond a certain level, then this “indicates a need” to reduce the amount of the drug in subsequent administrations (since the drug would generate toxic side-effects).
The court found that the claimed method did not require any action other than determining the correlation between drug administration dosages and metabolite levels in the blood. However, the mere determination of this correlation and/or the determination of the threshold of inefficacy versus harmfulness was found insufficient to impart patentability to the claim, because it merely reflected the discovery of a law of nature independent of human interaction.
The decision highlights the court’s view that merely determining a correlation or measuring a parameter, absent further human intervention, is insufficient to transform unpatentable laws of nature into patent-eligible applications of those laws.
Additionally, the court noted that the remaining steps claimed in the method, even if considered as limitations, would nevertheless be insufficient to impart patentability as they were routine steps known in the art.
It follows that diagnostically valuable findings may not be patentable in the US unless the diagnostic process comprises steps in addition to the step of diagnosis itself. That is, patentable claims will likely require steps actively applying the “laws of nature”, which steps or combinations of steps must additionally be uncommon and/or not merely routine applications of the “laws of nature”.
A different approach
The EPO has a fundamentally different approach to assessing the patentability of diagnostic methods. By virtue of law (previously article 52(4) EPC, now article 53(c) EPC), diagnostic methods practised on the human or animal body are excluded from patentability. Ten years ago, the office’s Enlarged Board of Appeal clarified in its opinion G1/04 that diagnostic methods are excluded from patentability only if they comprise all of the following steps:
