News

Don't treat a subject; treat a disease

06.09.18

How closely must the language of a subsequent medical use claim match the language approved by the European Patent Office (EPO)? The revocation of a European patent during Opposition suggests the EPO may be tightening practice in this area. An Opposition Division has insisted that claims primarily referring to treating a subject, rather than treating a disease, are not limited to treatment of the disease.

Background

A product for use in a method of treatment may be protected by a European patent.  It is, however, necessary to use the EPO’s “medical use claim” format. There are two categories of medical use claim:

1. “First” medical use claims. A first medical use claim is granted when a product is not known for use in medicine and the use in medicine is inventive. They typically take the following format:

·         “Product X for use as a medicament”

2. “Subsequent” medical use claims. A subsequent medical use claim is granted when a medical use of a product is known, but a further use in medicine is not known and is inventive over any prior art. They typically take the following format:

·         “Product X for use in the treatment of disease Y”

The Decision

European patent no. 2287192 was granted on 26 August 2015 to Novartis Vaccines and Diagnostics, Inc. Oppositions were filed by three parties. The patent was revoked following oral proceedings.

Claim 1 as granted reads (emphasis added):

An M-CSF antagonist, for use in:

a) preventing bone metastases in a subject afflicted with metastatic cancer;

b) preventing, in a subject afflicted with metastatic cancer, bone loss associated with the cancer;

c) treating a subject afflicted with a metastatic cancer to bone,

d) reducing, in a subject afflicted with a metastatic cancer to bone, the severity of bone loss associated with the cancer,

e) treating a subject suffering from osteolytic bone metastases, or

f) treating a subject suffering from bone loss associated with cancer metastasis,

wherein said antagonist inhibits the interaction between M-CSF and its receptor (M-CSFR) and is selected from the group consisting of:

i) a polypeptide comprising an anti-M-CSF antibody; and

ii) a polypeptide comprising an anti-M-CSFR antibody.

In Reasons for the Decision 4.2.2, the Opposition Division explained that none of alternatives a) to f) uses the approved format for a subsequent medical use. The reasoning for alternatives a), b), and d) is not of interest for the purposes of this article.

Alternatives c), e) and f) were singled out as failing to define a disease by name. This problem has been seen previously, for example in T 1748/15 where the term “tooth wear” failed to exclusively define a pathological condition; it also covered physiological wear.

However, a new rationale appears to operate in this case. The failure to define a disease here stems from the common formulation of alternatives c), e) and f) as “treating a subject”. This is made especially clear by the contrasting result for Auxiliary Request 4 (see below). Most likely the thinking is that the subject may have any number of diseases, in addition to the disease described. Which disease is being treated? Therefore, treating a subject with a certain disease does not necessarily equate to treating that disease.

Since none of the alternatives defined a subsequent medical use, but did relate to a use in medicine, all alternatives were interpreted as first medical use claims. As described above, first medical use claims can only be valid when a product is not known for use in medicine.  In this case, the specified antibodies were already known to be used in medicine as inhibitors of metastasis. Therefore, claim 1 as granted lacked novelty.

However, Auxiliary Request 4 was found to define novel subject matter. The differences between the Main Request and Auxiliary Request 4 are therefore instructive.

Claim 1 of Auxiliary Request 4 reads (emphasis added):

An M-CSF antagonist, for use in:

a) treating osteolytic bone metastases in a subject suffering from osteolytic bone metastases, or

b) treating bone loss associated with cancer metastasis in a subject suffering from bone loss associated with cancer metastasis,

wherein said antagonist inhibits the interaction between M-CSF and its receptor (M-CSFR) and is selected from the group consisting of:

i) a polypeptide comprising an anti-M-CSF antibody; and

ii) a polypeptide comprising an anti-M-CSFR antibody

Alternatives a) and b) in claim 1 of Auxiliary Request 4 are based on alternatives e) and f) of the Main Request. They have each been amended to more closely match the approved subsequent medical use format. This has been done by primarily referring to treating a disease (osteolytic bone metastases and bone loss associated with cancer metastasis). The alternatives still refer to a subject. However, the reference to the subject is now secondary. The claims now specify treating a disease; not a subject.

Claim 1 of Auxiliary Request 4 was held to define novel subject matter accordingly. However, the Opposition Division decided that Auxiliary Request 4, and all subsequent Requests, lacked inventive step.

Since no Requests on file met the requirements of the EPC, the patent was revoked by the Opposition Division. 

The outcomes

The proprietor has until 9 September 2018 to file an appeal against the decision. At the time of writing, no appeal has yet been filed. It will, therefore, be interesting to see whether the patentee escalates the question at the EPO.

In the meantime, anecdotal evidence suggests that EPO Examiners have discussed this Decision and are adapting their practice accordingly. Time will tell whether the Decision will be developed into a general examination policy. 

Practice points

Even if the rationale of this decision is adopted more widely in the EPO, it is unlikely to prove fatal for applicants or patentees, for the following reasons.

A medical use claim treating a subject rather than a disease may be a tempting target in opposition. This is because of the opportunity to raise novelty as a ground for opposition. However, as shown by this Decision (Auxiliary Request 4), reformulation of the claim in question should resolve the issue. In principle, reformulation from an (unintended) first medical use claim to a subsequent medical use claim should not offend the post-grant prohibition against broadening amendments (Article 123(3) EPC). This is because a subsequent medical use claim is inherently narrower than a first medical use claim.

Central limitation before the EPO is also expected to be available, for corresponding reasons. This procedure may be of interest to any proprietors concerned about granted patents containing medical use claims referring to treatment of a subject rather than treatment of a disease.

Amendments before litigation may also be advantageous. Ensuring medical use claims refer to treatment of a disease, rather than a subject, may help streamline proceedings before national courts that agree with the logic of this Decision.

Finally, the Decision acts as a reminder to practitioners prosecuting European patent applications. Take care when drafting subsequent medical use claims or especially when reformulating method of treatment claims into subsequent medical use claims.

For more information or advice, please contact Michael Newton or your usual Kilburn & Strode advisor.