Knowledge & News

Partial priority and the “first application” at the EPO

19 March 2018

Decision T 0282/12 of the Boards of Appeal of the EPO recently published. This decision takes account of the Enlarged Board’s decision on partial priority (G 1/15) and shows that partial priority may also apply when considering whether an application from which priority is claimed is the “first application”.

For a claim to priority to be valid, the EPO requires (mirroring the language of the Paris Convention) the application from which priority is claimed to be the “first application” disclosing that subject matter.

In the present decision, the Board had to consider the validity of the priority claim of patent EP1773302. In particular, the Board had to consider whether the granted patent’s priority claim was invalid in view of an earlier document which was the “first application” from which priority should have been claimed. The patent and the application from which priority was claimed were directed to a tablet having, amongst other features, a gelatinous first and second coating, a gap being provided between the two gelatinous coatings of from 3 to 33% of the length of the tablet.  However, the patentee had filed an earlier application (US 2005/0152970, D22) which was identical to the granted patent, except that the disclosed gap was 5 to 33%.

The Board’s decision focused on the concept of partial priority, which was clarified in the recent Enlarged Board of Appeal Decision G1/15. Although this G Decision was mainly concerned with the concept of “poisonous divisionals”, the Board decided that the rationale of this decision also applied here.

The Board agreed that amending a range of 5 to 33% to a range of 3 to 33% would result in added matter. However, since the concept of “partial” validity of an amendment does not exist, the Board stated that performing an Article 123(2) EPC test to examine the validity of priority may, in some circumstances lead to the wrong conclusion.

As both inventions encompassed an identical part (5-33%) the Board held that the inventions of D22 and the priority application were partly the same. It was also noted that it would be unjustified to grant an entirely new priority claim in respect of subject matter previously disclosed where alternative subject matter has been added. Otherwise, an applicant could indefinitely postpone a priority date. As such, the priority claim was only partially valid.

Consequently, a relevant public use, which occurred after the priority date but before the filing date was considered to be full prior art and so became relevant for inventive step in relation to the subject matter which was not entitled to priority (5-33%).

This Decision clarifies that the concept of partial priority applies not just to divisional applications but to any priority claim. Based upon this, applicants should be aware that prior art filed after the priority date but before the filing date of an application can become relevant for the assessment of inventive step as well as novelty, if the claim to priority is found to only be partially valid.


Laura Carney

Laura Carney Trainee Patent Attorney Birmingham (UK)

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