Art. 88(2), second sentence, EPC provides that, where appropriate, multiple priorities may be claimed for any one claim.
In T 828/93 (see point 4.2 above) the board confirmed that, because of the legal situation explained above, the possibility mentioned in Art. 88(2) EPC 1973 of multiple priorities for any one patent claim related only to instances where, unlike in the case at issue, the claim contained alternatives and could therefore be split into several subject-matters. See also G 2/98 below.
In T 620/94 it became apparent that the granted claim 1 covered two alternatives A and B of the invention. Only alternative B was disclosed in the priority document; alternative A was contained only in the subsequent European application. Prior art published during the priority interval rendered obvious alternative A. The patent could thus only be maintained in amended form, i.e. limited to alternative B.
In T 441/93 the European patent related to a process for preparing a strain of the yeast Kluyveromyces, which comprised transforming Kluyveromyces yeast cells with a vector comprising, inter alia, a DNA sequence encoding a polypeptide. The invention disclosed in the priority document was a process for the preparation of new strains of the yeast Kluyveromyces, characterised in that protoplasts of such yeast were mixed with and transformed by vector molecules. The board concluded on the evidence that the references to protoplasts in the priority document were of crucial importance and that no mention had been made in it of the possibility of transforming whole cells. It was decisive what process had been disclosed in the previous application since claim 1 of the subsequent application was directed to a process. In so far as claim 1 covered whole cell transformation, it could only be entitled to the filing date of the European application. The board's conclusion was that the claims could be divided into two groups: Group A, enjoying priority rights from the previous application and comprising claim 1 in so far as directed to a process for the transformation of Kluyveromyces protoplasts, and the related further claims; and Group B, only enjoying the priority of the subsequent European application, and comprising claim 1 in so far as not directed to a process for the transformation of protoplasts, and the related further claims.
In G 2/98 (OJ 2001, 413) the Enlarged Board of Appeal analysed the legislative intention behind Art. 88(2), second sentence, EPC 1973 and concluded that a distinction has to be drawn between the two following cases. The legislator did not want several priorities to be claimable for the "AND" claim (e.g. a claim to features A and B, with the first priority document disclosing claim feature A alone and only the second priority document disclosing claim feature B). With regard to the "OR" claim the Enlarged Board drew the following conclusion from the historical documentation relating to the EPC 1973: where a first priority document disclosed a feature A, and a second priority document disclosed a feature B for use as an alternative to feature A, then a claim to A or B could enjoy the first priority for part A of the claim and the second priority for part B of the claim. It was further suggested that these two priorities might also be claimed for a claim directed to C, if the feature C, either in the form of a generic term or formula, or otherwise, encompassed feature A as well as feature B. The use of a generic term or formula in a claim for which multiple priorities were claimed in accordance with Art. 88(2), second sentence, EPC 1973 was perfectly acceptable under Art. 87(1) and 88(3) EPC 1973, provided that it gave rise to the claiming of a limited number of clearly defined alternative subject-matters.
In T 665/00, the appellant (opponent) had raised an allegation of public prior use within the priority interval and had challenged the validity of the priority claim. According to the board, the subject matter of the alleged prior use was both described in the priority document and fell within the scope of the claims of the disputed patent, but the priority document did not necessarily describe all the subject-matters claimed. The board observed that, under Art. 88(3) EPC 1973, the right of priority covered only those elements of the patent application included in the application from which priority was claimed. Different elements of a patent application could have different priority dates. According to G 2/98 (OJ 2001, 413), the approach of recognising different priority dates also applied to a claim using a generic term or formula, provided that the use of such a term or formula gave rise to the claiming of a limited number of clearly defined alternative subject-matters. For the case in hand, the board concluded that, of the different alternatives contained in claim 10 of the disputed patent (relating to a powder containing hollow microspheres the specific mass of which was described by the generic term "less than 0.1 g/cm3"), the non-compacted powders containing "Expancel DE" microspheres were covered by the claimed date of priority. The claimed prior use, which involved a product containing the same "Expancel DE" microspheres, could therefore not be novelty-destroying.
See also T 1443/05 (also referred to in point 2.1.7 above), in which the board concluded that the generic wording of claim 1 did not reveal any clearly defined alternative subject-matters which could have justified the priority right.
In T 1877/08 the patentee had argued that at least for the overlapping portion of the ranges disclosed respectively in claim 1 of the patent in suit and in the priority document, the subject-matter of claim 1 was entitled to the first priority date. Referring to G 2/98 (OJ 2001, 413), the board held that the claimed amounts represented a continuum of a numerical range of values not corresponding to distinctive alternative embodiments. Consequently, no separable alternative embodiments, i.e. elements in the sense of Art. 88(3) EPC, could be identified within that continuum. Hence, the subject-matter of claim 1 as a whole was not entitled to the claimed priority date.
However, in T 1222/11 the board remarked, in relation to the "OR"-claim situation, that the condition "provided that it gives rise to the claiming of a limited number of clearly defined alternative subject-matters" (see G 2/98 above) should be given a different meaning from that attributed to it in T 1877/08, T 476/09, T 1443/05 and T 1127/00. This condition could not be meant to set out the manner in which the subject-matter of the "OR"-claim must be defined. This would, at least in relation to generic terms, be at variance with the disclosure test based on the principle of an unambiguous and direct disclosure (cf G 3/89, OJ 1993, 117). For the purpose of the assessment required by Art. 88(3) EPC, the board considered that the wording of the above condition referred to the ability to conceptually identify, by comparison of the claimed subject-matter of the "OR"-claim with the disclosure of the multiple priority documents, a limited number of clearly defined alternative subject-matters to which the multiple rights of priority claimed could be attributed or not (cf. examples in the Memorandum drawn up by FICPI (M/48/I, Section C) for the Munich Diplomatic Conference in 1973, as cited in G 2/98).