No admission after the show has started - transfer of priority right must occur prior to filing of subsequent application (T 577/11)

According to Article 87(1) European Patent Convention, any person who has duly filed, in or for any state party to the Paris Convention or any member of the WTO, an application for a patent or his successor in title, shall enjoy, for the purpose of filing a European patent application in respect of the same invention, a right of priority during a period of twelve months from the date of filing of the first application (emphasis added). The reference to the "successor in title" in Article 87(1) EPC is generally interpreted as requiring a transfer of the right of priority before the filing of the subsequent application (T 205/14, Reason 3.4). 

In T 577/11 of 22 March 2017, Board of Appeal 3.2.05 confirmed this. Transfer of the priority date had undoubtedly taken place in this case, but three days after the filing of the subsequent application. The applicant argued that Article 87(1) EPC did not require that the transfer of the priority right had to occur prior to the filing of the subsequent application. The Board, based on the wording of Article 87(1) EPC and noting that its interpretation was in line with Article 4A(1) Paris Convention and the legislative history of both the relevant provisions of the Paris Convention and the EPC, rejected the appellant’s argument. The transfer had to had taken place by the time the subsequent application was filed. 

The Board notes that German case law considers the date the declaration of priority with the particulars relating to the priority application is filed – which can be done up to 16 months from the earliest priority date claimed (Rule 52(2)), and therefore up to four months after the filing of the subsequent application – as the relevant date (German Federal Patent Court, decision of 15 February 2012, 5 Ni 59/10 (EP), Reasons, point I.2, and decision of 28 October 2010, 11 W (pat) 14/09), Reasons, point II.B.2(a)(cc)). In the case at hand, Rule 52(2) was not applicable because the application that led to the patent was a PCT application. Under Rule 4.10(a) PCT, the declaration was to be made on filing the subsequent application, which it was. Nonetheless, the Board indicates that even if the present application had not been a PCT application, it did not consider the German approach convincing, as the filing of the declaration of priority was a “mere formality” that did not change the relevant date, which was the filing date of the application.

The decision does not come as a great surprise. There has long been a consensus that the transfer of a priority right must occur prior to the subsequent filing. However, given the careful reasoning and the amount of space the Board dedicates to the issue, T 577/11 may be considered the leading case on this for the coming years. The take-away for applicants and their representatives is that they better get those assignments signed prior to filing the subsequent application, or else the curtain falls on the priority claim.