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Double-patenting and second medical use claims – new guidance from the EPO boards of appeal

The recent EPO board of appeal decision “Cancer treatment/Board of Regents, the University of Texas System” (T 1780/12) sheds light on current EPO practice on double-patenting, and also highlights the distinction between the old and new types of second medical use claim.

The decision related to a divisional application with a main claim directed to “a composition comprising [antibody X] for the treatment of cancer”, which is in the currently accepted format for second medical use claims under Article 54(5) EPC. The parent application had a main claim directed to “Use of a composition comprising [antibody X] in the manufacture of a medicament for the treatment of cancer”, which is in the “Swiss type” claim format accepted for second medical use claims before the current version of the EPC came into force.

In other words, the divisional application claimed the same invention as its parent application but in a different format. The question before the board was whether this constituted double-patenting, in which case the divisional application should be refused. The test for double-patenting is whether the claims of the two applications are directed to “the same subject-matter”.

The EPO examining division had decided at first instance that the two claims did relate to the same subject matter. Their reasoning was that the invention claimed is the same and the EPC legislator had intended for the new second medical use claim format to be equivalent to the old Swiss type claims. Hence, the examining division found that double-patenting would occur if the divisional application was granted.

The board of appeal disagreed with this reasoning and decided that the new second medical use claim format is a different category of claim compared to the old Swiss type claim. In particular, the new claim format is a purpose-limited product claim, whereas the old format was a purpose-limited process claim, requiring in addition the manufacture of a medicament. The board acknowledged that the scopes of these two types of claim overlap, but found that they were not the same. Support for this was found in previous board of appeal decisions establishing that the scope of protection of a process claim is narrower than that of a product claim, and in the fact that the manufacture of a medicament is an additional technical feature that is not present in the new claim type.

In view of the difference in claim category, the board found that there was no double-patenting in this case. This conclusion is important for two reasons. Firstly, it makes clear that the two types of second medical use claim cannot be assumed to be equivalent in scope, despite that being the original intention of the legislator. Claims in the new format are likely to have a broader scope of protection than an equivalent claim in the old Swiss type format.

More generally, the decision establishes that two applications may claim the same invention without double-patenting, provided that the claims concerned are in different categories and/or differ in at least one technical feature. The claims of the two applications may overlap provided that they are not identical in scope.

If you have any questions on this issue or any other aspect of patent law, please contact Matt Turner at or .

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