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Case Law of the Boards of Appeal

Cases of non-disclosure of an essential feature 

In T 923/92 (OJ 1996, 564) the board maintained a patent on a process comprising the preparation of a protein with (further specified) human tissue plasminogen activator function. The subject-matter of the claim was defined by means of reference to an amino acid sequence. The sequence contained in the European application was disclosed for the first time in the third priority document (P3). It differed from the sequence reported in the first and second priority documents (P1 and P2) in respect of three amino acids.

The board held that only the priority of P3 could be claimed. In the board's judgment, the skilled person would consider the primary amino acid structure of a protein to be an essential feature thereof because it represented its chemical formula. He would therefore consider the reference to the amino acid sequence of a protein as having not merely an informational character but as being a primary technical feature linked to the character and nature of the product. When comparing the sequences reported in P1/P2 and in P3, the skilled reader could not know whether, in spite of the differences, the sequences were identical in their physical and biological characteristics; at least on paper the quoted replacements of amino acids could imply important structural and functional differences. The evidence submitted by the patentee was understandably restricted to the testing of a limited number of parameters and left open the possibility that the two polypeptides could differ in many other properties (see also below point 2.1.10 "Inventions relating to nucleotide and amino acid sequences").

In T 1052/93 it was an essential feature of the wash adjunct products claimed in the European patent that they contained sodium perborate monohydrate in conjunction with a functionally defined activator. The priority document only mentioned certain activators complying with the functional definition in the European patent; these specific compounds could not be considered to disclose the broad group of activators functionally defined in claim 1 of the European patent. See also T 132/09.

In T 1054/92 of 20.6.96 claim 1 contained the feature that the absorbent structure had a moisture content of less than 10%. This feature could not be derived from the disclosures in the first and second priority documents. The said upper limit was only introduced by the third priority document. The board could accord to the subject­matter of claim 1 only the third priority date. The feature concerning the moisture content of less than 10% was an essential element. The relevant feature appeared in claim 1 as originally filed and was relied upon by the appellant in the examination proceedings when seeking to distinguish the subject-matter of this claim from cited prior art.

In T 277/95 the board found that a claim to a method of producing in CHO cells hEPO characterised by the presence of a specific glycosilation pattern did not enjoy priority from a priority application which made available the cell line but gave no information on the specific glycosilation pattern.

In T 479/97 a first priority document characterised the pelC gene claimed in the subsequent application as being on a 5kb DNA fragment which was carried by a deposited plasmid. The board found that even if the sequence of the DNA fragment was known this did not necessarily imply that the provision of this fragment made available in a direct and unambiguous manner a specific gene which it contained, if only because the 5kb fragment which was bigger than the gene of interest might carry more than one gene.

In T 908/09 the board concluded that the priority document did not clearly allocate to one single group the classes of substances which were named in granted claim 1 as components b). Accordingly, the skilled person could not derive directly and unambiguously from the priority document a mixture of at least one substance a) with at least one substance b), as was required by claim 1.