T1831/16

02.09.2022


European patent No. 2 522 717 is based on European patent application No. 12 160 789.9, entitled "Oligopeptide-free cell culture media", filed as a divisional application of the earlier European patent application No. 07702574.0 (EP 1 974 014).

An opposition division decided that new auxiliary request 4, submitted during oral proceedings, met the requirements of the EPC.

The patent proprietors and opponent 1 (hereafter appellant I and appellant II, respectively) lodged an appeal against the decision of the opposition division.

Claim 1 according to the main request reads as follows:

"1. A method for expressing at least one protein, comprising the steps of:

 (a) providing a culture of cells;

 (b) introducing at least one nucleic acid sequence comprising a sequence coding for at least one protein selected from the group of coagulation factor VII, coagulation factor VIII, coagulation factor IX, vWF, ADAMTS 13 and furin into the cells;

 (c) selecting the cells carrying the nucleic acid sequence; and

 (d) expressing the protein in the cells in a protein-free cell culture medium that does not comprise oligopeptides, the cell culture medium comprising at least 0.5mg/L of a polyamine."

Appellant I contended that one object of the invention disclosed in document D4 was to reduce plant and/or yeast derived hydrolysate to overcome inhibitory effects affecting the recombinant production yield by adding polyamine.

Although the term "and/or" in Example 2 of document D4 disclosed apparently a method using a medium containing putrescine but no soy hydrolysate, a more detailed analysis of the experiments and of the corresponding figures showed that none of the media contained only polyamine and no soy hydrolysate. Thus, the "and/or" reference in the section describing some experiments did not reflect what was done and what was actually disclosed in an enabling way. A disclosure could only be prejudicial to novelty if it was also enabling.

First, the board accepts that document D4 primarily relates to a method for expressing a recombinant protein in cells which are cultivated in an animal protein free medium comprising both polyamines and a plant- and/or yeast hydrolysate.

Secondly, document D4 discloses in Example 2 cell cultures of recombinant mammalian cells which were grown in suspension. Since, in order to be reproduced by the skilled person, the cells stably expressing Factor VIII require first a step of selecting the cells having been transformed and having integrated the nucleic acid sequence in their genome, the method described in document D4 must implicitly comprise steps (a) to (c) defined in the method of claim 1. In a further step, the culture of these cells in BAV medium was supplied with a constant feed of BAV medium supplemented with soy hydrolysates in the range of 0,1-1,0% and/or addition of putrescine.2HCl in the range of 0-1 mg/L.

Hence, the method of expressing recombinant FVIII may explicitly be carried out in BAV medium supplemented with either soy hydrolysate or putrescine.2HCl or alternatively with soy hydrolysate and putrescine.2HCl.

Even if example 2 does not report any experiments of culturing cells for the production of recombinant proteins using a medium comprising polyamines and no soy hydrolysate, the disclosure in a prior art document is not confined to the specific working examples, but comprises any reproducible technical teaching described therein. In other words, subject-matter which is explicitly disclosed in a prior art document but not exemplified cannot be dismissed as non-existent.

According to the established case law, the relevant question is not whether the skilled person actually had carried out each and every embodiment disclosed in the prior art document but rather whether the disclosure is sufficient to enable the skilled person, in combination with its common general knowledge, do so.

Since appellant I provided no evidence that the method in example 2 of document D4 could not be performed, they failed to discharge their burden of proof, with the consequence that their unfounded allegations cannot be taken into account by the board.

Absent any evidence to the contrary, the board is satisfied that the skilled person is able to carry out the method of culturing GD8/6 cells in suspension for the production of recombinant factor VIII using a medium comprising polyamines and no soy hydrolysate as explicitly disclosed in example 2 of document D4.

Since, the method described in document D4 anticipates the method of claim 1, the main and sole request lacks novelty (Article 54 EPC).

The patent is revoked.


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