Double Patenting and the Importance of the Format of Second Medical Use Claims in Europe

In a recent decision (T 1780/12) a Board of Appeal of the European Patent Office (EPO) has given its view on double patenting and the scope of protection provided by second medical use claims in different formats.

The applicant of a European patent application (hereinafter EP2) had filed an appeal against the Examining Division´s decision to refuse the application. EP2 was a divisional application of a European patent application that had been granted (hereinafter EP1).

The claims objected to in EP2 were second medical use claims in the new European format, i.e. purpose-limited product claims. The corresponding claims in EP1 were second medical use claims in Swiss-type format, i.e. purpose-limited process claims.

According to the Examining Division the different formats of the second medical use claims should be considered to be equivalent. As a consequence, EP2 was found to claim the same subject-matter as EP1 and was held unallowable for reasons of double patenting.

The Boards of Appeal (BoA) did not agree. Referring to decision T 1391/07 it says that the practice of double patenting is confined to patents and patent applications directed to the same invention as defined by the subject-matter of the corresponding claims and therefore confined to claims conferring the same scope of protection.  Regarding the scope of protection in the present case, the BoA states that the scope of protection provided by a purpose-limited process claim is less than that of a purpose-limited product claim. Accordingly, the scope of protection provided by EP1 and EP2, respectively, was found to differ (albeit with a partial overlap) so that there was no double patenting.

The Boards of Appeal also refers to decision T 250/05 in which a change in claim category from a Swiss-type second medical use claim into a second medical use claim being a purpose-limited product claim in opposition proceedings was found unallowable for the reason that the European Patent Convention (EPC) prohibits extension of the scope of a granted claim (Art. 123(3) EPC). In other words, this case supports the view that there is a difference in the scope of protection provided by, on the one hand, Swiss type second medical use claims and, on the other hand, second medical use claims being purpose-limited product claims.

In conclusion, it remains to be seen if the EPO will follow the approach above or if questions regarding double patenting and the scope of protection provided by the different formats of second medical use claims will be referred to the Enlarged Board of Appeal for clarification.

// Louise Tottie