09 April 2020

New patient subgroups – can treatment history confer novelty?

EPO case law update – T 1491/14

The EPO’s Technical Board of Appeal 3.3.01 in recent decision T 1491/14 has provided further insight into the criteria suitable for establishing novelty of second medical use claims based on the treatment of a purposively selected patient subgroup. In particular, this decision has affirmed that second medical use claims directed towards the treatment of a patient subgroup – selected based on its treatment history – with a known medicament is novel over the prior treatment of a broader patient group with the same medicament.

Previous EPO case law has established that the use of a known therapeutic compound in the treatment of the same disease as that disclosed in the prior art can nevertheless constitute a novel therapeutic application, provided that it is carried out on a new group of subjects. These subjects are required to be distinguished from the former group by either physiological or pathological status. In the earlier decision T 233/96, the EPO’s Technical Board of Appeal took the view that the claimed subgroup must not overlap with the previously treated group of patients, and the choice of patient subgroup must not be an arbitrary selection (i.e. there must be a functional relationship between the distinguishing physiological or pathological status of the new group and the therapeutic effect). Recently, in T 694/16, the Board departed from the ruling in T 233/96, and held that novelty could be established for a patient subgroup that overlaps with a larger population of previously treated patients if the identifying feature of the subgroup (in this case, biomarkers that are predictive of responsiveness to treatment) was not previously known in the art (and there is a functional relationship between this feature and the therapeutic effect). This approach has now been followed in the present decision T 1491/14, which provides further clarity to the criteria used to assess whether a patient subgroup represents a purposive selection that imparts novelty to a second medical use claim.   

The decision in T 1491/14 concerns a medicament for treating depression, anxiety, abuse or chronic pain, in a patient who has previously ceased or reduced another medication for the treatment of the same disease due to sleep or sexually related adverse event. The Board had to assess whether this particular patient group was suitable to render the claimed therapeutic use novel.

In Appeal proceedings following Opposition, the Patentee put forward 3 criteria for assessing whether a group of patients renders a previously known therapeutic use novel. These criteria are as follows:

  1. The patient group is not disclosed in the relevant prior art.
  2. The patients belonging to the group can be distinguished from those of the prior art by their physiological or pathological status.
  3. There is a functional relationship between their characterising physiological or pathological status and the therapeutic treatment and thus the selection of the patients is not arbitrary.

The Board of Appeal agreed that a patient group fulfilling those three criteria would be suitable to meet the requirements of novelty, and considered each of these three criteria in turn.

On considering criterion (1), the Board of Appeal held this to be fulfilled because the new group of patients were undisclosed in the prior art, which described the treatment of patients who were suffering from depression, anxiety, abuse or chronic pain but did not specify the treatment history of the patients. Thus, even though the new subgroup of patients could have been embedded in or overlapped with the previous group of treated patients (which might have included patients who ceased another medicament due to side effects), the Board considered the subgroup to be novel, because the identifying feature of the subgroup (i.e. the treatment history) was not previously disclosed in the art. This is consistent with the ruling in T 694/16.

With respect to criterion (2), the Board held that the patients’ decision to continue, reduce, or cease medication due to adverse effects is not an arbitrary choice based on the patients’ free will but rather a technical decision comparable to that of a physician selecting the most suitable treatment for a patient. The Board took the view that the patients’ decision to cease the previous treatment due to the burden of the sleep or sexually related side effects represented a failure of the previous treatment that would affect the patients’ mental health and their attitude towards antidepressants and, as such, makes the new group of patients different from a pathological point of view. In this regard, the Board held that the treatment history of the patients of the new group makes them pathologically distinct from the prior art patients (whose treatment history was not known) and that criterion (2) is fulfilled.

Finally, with regard to criterion (3), the Board noted that the claimed treatment produces sleep and sexually related adverse events at (or close to) the level of placebo. As such, it is particularly suitable for treating depression, anxiety, abuse or chronic pain in patients who took the decision to reduce or cease a previous medication due to the occurrence of such adverse events. Therefore, it was held that the functional link between the pathological status of the patients and their therapeutic treatment is clear, and criterion (3) is fulfilled.

This decision thus provides a set of criteria that may be useful for assessing whether a patient subgroup represents a purposive selection that imparts novelty to a second medical use claim. These criteria allow novelty to be acknowledged even where there is an overlap between the new patient subgroup and a larger group of previously treated patients as long as the subgroup patients can be distinguished pathologically or physiologically from the prior art patients – consistent with the ruling in T 694/16. Furthermore, the decision paves the way for claims directed to the treatment of new patient subgroups in circumstances where a known treatment is found to be particularly beneficial for patients having a particular treatment history. The Board of Appeal’s decision in T 1491/14 thus re-affirms the EPO’s approach to allowing protection for a range of personalised healthcare inventions.