Personalised medicine, also referred to as precision medicine, can be regarded as the tailoring of a medical treatment to the individual characteristics of a patient.

Typically, claims to personalized medicine inventions are drafted as follows:

‘Compound X for use in treating disease Y in a patient with biomarker Z.’

A decision by the EPO’s Technical Board of Appeal (T0694/16) has clarified that claims to purposively selected patients for treatment with a known drug is considered to be novel over the prior art treatment of a broader and/or overlapping patient group with the same drug.

The question of interest in this case was whether limiting a medical use by specifying the patient to be treated as having biomarker Z will confer novelty if (i) the prior art is silent about patients having the biomarker Z but (ii) a treatment of at least one patient having the biomarker Z appears to be inevitable.

This case related to a personalized medicine claim in which a specific composition was specifically administered to prodromal patients (patients who do not suffer from senile dementia but have an increased likelihood to develop senile dementia, such as Alzheimer’s disease). The patent in question disclosed specific markers (referred to as CSF markers) which allowed for the identification of prodromal patients which could be further distinguished from dementia patients.

The Opposition Division had revoked the patent stating that it lacked novelty in view of documents which taught the use of the claimed composition for the treatment and prevention of Alzheimer’s disease. The Opposition Division had considered that the specific subgroup of patients had ‘inherently’ been treated in the prior art documents.

This differed from the conclusion reached by the Board of Appeal in which the question of ‘inherency’ was held to be irrelevant when assessing novelty. The Board of Appeal stated that ‘the skilled person would promptly understand that the purpose of the treatment is to target selectively prodromal patients identified by their CSF markers, rather than other subjects that do not display the markers. This implies that there is a functional relationship between the markers that characterise the patients and the therapeutic effect which is sought. The presence of this functional relationship confirmed that the purposive selection of patients is an essential technical feature qualifying claim 1. This has to be taken into account when assessing novelty.’ Furthermore, the Board of Appeal considered that ‘the only thing which counts is that the prior art does not disclose a method whereby a patient or a group of patients displaying the relevant specific markers but not affected by dementia was purposively and selectively targeted for carrying out the preventive treatment defined in claim 1.’

This case illustrates that in order to anticipate a personalized medicine claim, the prior art document must teach the specific selection and targeting of the subgroup of patients identified in the claims.

In practice, even if a drug has been used to treat a general group of patients, an individual that determines how to identify the patients that best respond to the drug may be able to secure a European patent which covers the drug’s use in the treatment of such purposively selected patients.

Interestingly, the EPO’s viewpoint on this matter which favours personalised medicine inventions differs to the restrictive position adopted in the US where the doctrine of inherency is considered to be relevant when assessing patentability.