T 0051/87 (Starting compounds) 08-12-1988

1. The appeal complies with Articles 106 to 108 and Rule 64 EPC and is, therefore, admissible.

2. The present appeal is concerned with the sufficiency of the disclosure under Article 83 EPC, allowably raised in opposition proceedings under Article 100(b) EPC.

3. The EPC requires that the disclosure of the invention must be clear and complete so as to be sufficient for a person skilled in the art to carry it out (Art. 83 EPC). In the present case, the invention as claimed in the main claim consists of the chemical transformations of a series of eight starting compounds (C-076 compounds), which transformations involve at least the following two compulsory steps: (a) removing the |-L-oleandrosyl-|-L-oleandrose group by hydrolysis; (b) replacing the hydroxy group resulting from step (a) with a halo group by reaction with a sufficiently reactive benzenesulfonyl halide in the presence of a base. From the wording of the claims, as well as from that of the description, it is clear that the invention as such does not cover the preparation of starting compounds, as those were all assumed to be known compounds. This is entirely consistent with paragraph 7 of Professor Ley's affidavit where he stated, inter alia, that "given supplies of the starting compounds as indicated, the subsequent chemistry as reported is more than adequate in preparative detail to permit a skilled synthetic chemist to repeat the transformations". This statement is not contradicted by the affidavits of either Professor Bull or Hough, which both indicate that once the starting compounds are available, their further transformation would cause no practical difficulty to a person skilled in the art, so that the disclosure of the patent in suit cannot in this respect be considered insufficient. Accordingly, the requirements of Article 83 appear to be satisfied, which was also the conclusion of the Examining Division, since it granted the patent without having called into question the sufficiency of the disclosure. It is significant in this respect that at the end of the appeal proceedings, even the Respondent no longer denied that the disclosure of the invention, as defined above, was actually sufficient.

4. However, the Respondent's objection goes wider than this, alleging that because in the description, as originally filed, the starting compounds had not been described at all, the man skilled in the art was not in a position to carry out the claimed invention. In the present case, the starting compounds to be used cover a series of eight chemically related compounds, called C-076 compounds, which are |-oleandrosyl-|-oleandroside derivatives of pentacyclic 16-membered lactones related to the milbemycins and designated A1a through B2b as follows: C-076 A1a, C-076 A1b, C- 076 A2a, C-076 A2b, C-076 B1a, C-076 B1b, C-076 B2a, C-076 B2b. The preparation, isolation and characterisation of these eight compounds is described in detail in document (5). The Respondent conceded that the information contained in document (5) was sufficient to prepare all eight starting compounds, and that a combination of this information with that contained in the patent in suit would have been sufficient to dispose of any practical difficulties in carrying out the claimed invention. However, this document had neither been mentioned in the priority documents, nor in the application as originally filed, nor for that matter in the patent in suit. Thus the sole question which arises is whether or not this document may be introduced into the description at the appeal stage of the proceedings, having regard to the provision of Article 123(2) EPC.

5. Document (5) relates to a new family of eight chemically related agents exhibiting anthelmintic activity, collectively identified as C-076 compounds, which are produced by a previously undescribed species of the genus Streptomyces, which has been named Streptomyces avermitilis. The document also describes a method for the recovery and purification of these compounds, which may be described by the structural formula indicated in the introductory part of the patent in suit where all eight compounds are described in detail (see page 2, line 40 et seq.) A comparison of the structural formula describing these known compounds with that of the compounds now claimed (cf. page 4, lines 1 to 41 of the description) shows that the C-076 starting compounds certainly belong to those compounds which are structurally the closest related to the derivatives obtained by the process described in the patent in suit. Document (5) therefore belongs to those documents which need to be taken into consideration when assessing inventive step, as had been done by the first instance at the very beginning of these proceedings. Thus the Examining Division correctly considered this document when assessing inventive step, although it selected another document as closest prior art (see Communication dated 6 May 1982, last paragraph). In the opinion of the Board, the inclusion of a reference to document (5) could not only have been done at this early stage of the proceedings without any difficulty, but should indeed have been done in view of the manifest relevance of this document. The Board cannot see why this document had not been specifically mentioned in the European Search Report, since: - both the starting compounds and their derivatives belong to the same subgroup in the hierarchy of the International Patent Classification, which is the smallest unit of the classification to be consulted for the search; - the Appellant repeatedly referred to this document when defending his case before the Examining Division, (see letters dated 28 January 1982 and 18 October 1982). Thus, notwithstanding that document (5) contains information necessary for carrying out the invention as claimed, it still undoubtedly belongs to the state of the art, and is probably even the closest prior art.

6. The Board is therefore of the opinion that the inclusion of document (5) in the description is permissible under Rule 27(1)(c) EPC, and is in line with a previous decision that the subsequent inclusion into a specification of a prior art document does not contravene Article 123(2) EPC (see decision T 11/82, "Control circuit/LANSING BAGNALL", OJ EPO 1983, 479, at point 22.

7. In the circumstances, it is indeed surprising that the Examining Division was fully satisfied with the information provided by the description as filed, although its attention had quite clearly been directed to the relevance of document (5) by a series of critical observations filed under Article 115 EPC. Be that as it may, the Examining Division did not make any use of the opportunity to introduce a reference to this document in the appropriate part of the description. A reason for this could be that some technical information not mentioned in the priority documents and concerning the preparation of the starting compounds had been included in the description when originally filed (see pages 47 to 51). However, no attempt to clear the origin of that information was made at the stage of examination of the application. This question was only touched upon at the opposition stage, which could explain why document (5) had not been recognised by the first instance as relevant background art in the sense of Rule 27(1)(c) EPC. If this had been done initially, the matter could have been settled right at the beginning of the proceedings, and so no question under Article 83 EPC would have arisen later on.

8. Although it follows from the above, that the inclusion of a reference to document (5) in the description is required by Rule 27(1)(c) EPC, and is permissible under Article 123(2) EPC, the Board wishes to deal also with the general question of common general knowledge as arising in these proceedings. From the two earlier published decisions mentioned in the course of the proceedings, i.e. decision T 171/84, "Redox Catalyst" and T 206/83, "Herbicides", the Respondent considered that the latter should not apply in the present case. In both decisions the same Board held that patent specifications were not normally part of the common general knowledge of the natural skilled addressee.

9. In the present case, the C-076 starting compounds are highly elaborated microbial metabolites opening a brand new field of research, so that any technical knowledge acquired in this field at the beginning, through basic pioneering work had not yet been distilled into the form of textbooks. By contrast, in the prior decision T 206/83 the situation was quite a different one, namely that the man skilled in the art was a person working in the field of classical herbicide chemistry, which was not a new developing field like that of the chemistry of C-076 compounds. The man skilled in the art, therefore, cannot be presumed to possess the same common general knowledge in both cases. Accordingly, the facts of the prior decisions are not on all fours with those of the instant case, which could, were this necessary, be decided on its own merits, with the result that document (5) would be considered as part of the relevant common general knowledge, thus defeating the allegation of insufficiency under Article 83 EPC.

10. It follows from the above that document (5) is to be included in the description of the patent in suit. Consequently, the Appellant's main request to maintain the patent in unamended form must be rejected. Since the description has not yet been amended in conformity with this request, the maintenance of the patent is therefore subject to the filing of a properly amended description by the Appellant. As matters stand, the Appellant's second auxiliary request has become purposeless.