1.5 Multiple priorities and partial priorities 

"Multiple priorities may be claimed" – i.e. a European application may claim rights of priority based on more than one previous application (G 2/98).

"Partial priority" refers to a situation in which only a part of the subject-matter encompassed by a generic "OR" claim is entitled to the priority date of a previous application (G 1/15).

The previous application may have been filed in or for the same or different states or members of the WTO, but in all cases the earliest application must have been filed not more than 12 months before the date of filing of the European application. Subject-matter of a European application will be accorded the priority date of the earliest priority application which discloses it.

If, for instance, the European application describes and claims two embodiments (A and B) of an invention, A being disclosed in a French application and B in a German application, both filed within the preceding 12 months, the priority dates of both the French and German applications may be claimed for the appropriate parts of the European application; embodiment A will have the French priority date and embodiment B the German priority date as effective dates. If embodiments A and B are claimed as alternatives in one claim, these alternatives will likewise have the different priority dates as effective dates.

If, on the other hand, a European application is based on one previous application disclosing a feature C and a second previous application disclosing a feature D, neither disclosing the combination of C and D, a claim to that combination will be entitled only to the date of filing of the European application itself. In other words, it is not permitted to "mosaic" priority documents. An exception might arise where one priority document contains a reference to the other and explicitly states that features from the two documents can be combined in a particular manner.

According to G 1/15, entitlement to partial priority may not be refused for a claim encompassing alternative subject-matter by virtue of one or more generic expressions or otherwise (generic "OR" claim) provided that said alternative subject-matter has been disclosed for the first time, directly, or at least implicitly, unambiguously and in an enabling manner in the priority document. No other substantive conditions or limitations apply in this respect.

In assessing whether subject-matter within a generic "OR" claim may enjoy partial priority, the first step is to determine the subject-matter disclosed in the priority document that is relevant, i.e. relevant in respect of prior art disclosed in the priority interval. This is to be done in accordance with the disclosure test laid down in the conclusion of G 2/98 and on the basis of explanations put forward by the applicant or patent proprietor to support the claim to priority, in order to show what the skilled person would have been able to derive from the priority document. The next step is to examine whether this subject-matter is encompassed by the claim of the application or patent claiming said priority. If the answer is yes, the claim is de facto conceptually divided into two parts, the first corresponding to the invention disclosed directly and unambiguously in the priority document, the second being the remaining part of the subsequent generic "OR" claim not enjoying this priority but itself giving rise to a right to priority as laid down in Art. 88(3).

For example, if the priority document discloses the use of a specific composition whereas the application claims the use of a composition defined in more generic terms, two alternative groups of subject-matters are identified as being encompassed by the claim, even if the claim does not expressly spell them out:

– alternative (a), concerning the use of a specific composition (e.g. calcium salt of the active ingredient and tribasic phosphate salt in which the cation was multivalent) and 

– alternative (b), concerning the use of a composition defined in more generic terms (e.g. acid form or acceptable salt thereof as the active, inorganic salt in which the cation was multivalent, wherein active ingredient and inorganic salt were other than calcium salt of the acid and tribasic phosphate salt in combination). 

Alternative (a) is the subject-matter disclosed in the priority document, not defined as such in the claim but encompassed by it. Alternative (b) is the remaining subject-matter of the claim, which was not disclosed in the priority document. In such a situation, the subject-matter of alternative (a) enjoys priority whereas that of alternative (b) does not.

The rationale of decision G 1/15 also applies in the context of deciding whether an application from which priority is claimed is the first application within the meaning of Art. 87(1). Just as a priority application and a patent claiming priority from it may partially relate to the same invention, the priority application and an earlier application filed by the same applicant may also partially relate to the same invention. In that case, the priority application would be the first application in respect of only that part of the invention which is not the same as in the earlier application (T 282/12).

Partial priority may also be transferable separately (T 969/14). This, however, has consequences for the remaining priority right because the assignor is left with a limited right and may no longer keep claiming that partial priority (an applicant can only claim a right which they own). The transfer agreement of the partial priority gives a respective partial priority right to the assignor and the assignee corresponding to two clearly distinct and precisely defined alternatives.