T 0694/92 (Modifying plant cells) 08-05-1996

1. The appeals are admissible.

The main request

2. No objections have been raised by the appellants under Article 123(2) and (3) EPC in respect of this request. ...

3. The present case is a typical example of a not uncommon situation - especially in the context of inventions in the field of biotechnology - in which the contribution to the state of the art by the invention disclosed in a patent or patent application resides in the actual realisation of a technical effect anticipated at a theoretical level in the prior art. In such a situation, a proper balance must be found between, on the one hand, the actual technical contribution to the state of the art by the invention disclosed in said patent or patent application, if any, and, on the other hand, the manner of claiming so that, if patent protection is granted, its scope is fair and adequate. This need for fair and adequate protection has been emphasised in several decisions of the boards of appeal (see, for example, T 292/85 above, and T 301/87, OJ EPO 1990, 335). The board deems it appropriate to consider the interrelation between the requirements of Articles 84, 83 and 56 EPC in order to find a fair balance in the present case.

4. Article 84 EPC requires that the matter for which protection is sought be defined in the claims in a clear and concise manner and that the claims be supported by the description. This means not only that a claim must be non-ambiguous and comprehensible, but also that all the essential features of the claimed invention have to be indicated in the claim, these being the features which are necessary in order to obtain the desired effect (see, for example, T 32/82, OJ EPO, 1984, 354, and T 1055/92, OJ EPO 1995, 214). The essential technical features may also be expressed in general functional terms, if, from an objective point of view, such features cannot otherwise be defined more precisely without restricting the scope of the claim, and if these features provide instructions which are sufficiently clear for the skilled person to reduce them to practice without undue burden, ie with no more than a reasonable amount of experimentation, and without applying inventive skill (see, for example, T 68/85 above). Although Article 84 EPC is not open to objection under the terms of Article 100 EPC, it may nevertheless constitute a proper ground for revoking a patent if objections to either clarity or support arise out of amendments to the patent as granted (see G 10/91, OJ EPO 1993, 420, point 19 of the Reasons). Furthermore, questions of clarity or support may affect the decision on issues under Article 100 EPC such as novelty (Article 54 EPC), inventive step (Article 56 EPC) or sufficiency of disclosure (Article 83 EPC) (see, for example, T 435/91, OJ EPO 1995, 188, and T 626/91 of 5 April 1995).

5. Article 83 EPC requires an invention to be disclosed in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. As made clear in T 409/91 (OJ EPO 1994, 653, see in particular points 3.3 to 3.5 of the Reasons), the extent to which an invention is sufficiently disclosed is highly relevant when considering the issue of support within the meaning of Article 84 EPC, because both these requirements reflect the same general principle, namely that the scope of a granted patent should correspond to its technical contribution to the state of the art.

Hence it follows that, despite being supported by the description from a purely formal point of view, claims may not be considered allowable if they encompass subject-matter which in the light of the disclosure provided by the description can be performed only with undue burden or with application of inventive skill. As for the amount of technical detail needed for a sufficient disclosure, this is a matter which depends on the correlation of the facts of each particular case with certain general parameters, such as the character of the technical field, the date on which the disclosure was presented and the corresponding common general knowledge, and the amount of reliable technical detail disclosed in a document (see decision T 158/91 of 30 July 1991).

In certain cases a description of one way of performing the claimed invention may be sufficient to support broad claims with functionally defined features, for example where the disclosure of a new technique constitutes the essence of the invention and the description of one way of carrying it out enables the skilled person to obtain without undue burden the same effect of the invention in a broad area by use of suitable variants of the component features (see T 292/85 above). In other cases, more technical details and more than one example may be necessary in order to support claims of a broad scope, for example where the achievement of a given technical effect by known techniques in different areas of application constitutes the essence of the invention and serious doubts exist as to whether the said effect can readily be obtained for the whole range of applications claimed (see T 612/92 of 28 February 1996). However, in all these cases, the guiding principle is always that the skilled person should, after reading of the description, be able to readily perform the invention over the whole area claimed without undue burden and without needing inventive skill (see T 409/91 and T 435/91 above). On the other hand, the objection of lack of sufficient disclosure presupposes that there are serious doubts, substantiated by verifiable facts, in this respect, see T 19/90 (OJ EPO 1990, 476, see point 3.3 of the Reasons).

6. Article 56 EPC requires the claimed invention, ie the proposed technical solution for a given technical problem, not to be obvious to a person skilled in the art. If the non-obviousness of a claimed invention is based on a given technical effect, the latter should, in principle, be achievable over the whole area claimed (see, for example, T 939/92, OJ EPO 1996, 309).

7. For the purposes of Articles 56 and 83 EPC the same level of skill is required from the person skilled in the art (see T 60/89, OJ EPO 1992, 268) in two different technical situations: whereas for the purpose of evaluating inventive step the skilled person has knowledge of the prior art only, for the purpose of evaluating sufficiency of disclosure (and, hence, support) he or she has knowledge of the prior art and of the invention as disclosed.

8. The above considerations show how closely interrelated and how critical the issues of support of the claims, sufficiency of disclosure and inventive step are in cases - such as the present one - where it is particularly difficult to find a proper balance between the breadth of the claims and the actual contribution to the state of the art by the disclosure of the patent in suit.

9. In the present case, the closest prior art is represented by document (5a). This document is a transcript of an oral disclosure by Dr J.D. Kemp which was made before the priority date. This disclosure included inter alia the construction of a DNA vector comprising T-DNA having inserted therein "the entire phaseolin gene including its own promoter regions" (see page 4, lines 7 to 8). Dr Kemp also stated: "But as you've heard, this has been done by a number of people now and nobody has shown a functional gene when one includes the endogenous promoter" (see page 4, lines 8 to 10). Although it is not immediately evident which reports Dr Kemp was referring to, it was known in the art that previous attempts to transfer a variety of bacterial, yeast and animal genes into plant cells did not lead to expression of the foreign genes because their own control sequences were not recognised by the plant machinery (see document (31)). Dr Kemp stated that he could not report the final experiment because "it hasn't been completed" (see page 4, lines 3 to 4). As it can be inferred from document (5a) (see passage starting on page 3 and continuing on page 4), this experiment consisted in the determination of whether transcription and translation would take place in plant cells subsequent to the transfer into them of the vector.

10. On examination of the description of the patent in suit, it can be observed that Examples 1 and 2 report the successful expression of detectable levels (on average 10 ng per gram tissue/fresh weight) of phaseolin in sunflower plant cells into which the DNA coding sequence was transferred with its own promoter via a T-DNA vector. In Example 3 manipulations of the gene for phaseolin and in Example 4 the removal of introns from the same gene are reported. Examples 5 to 8 describe mutated Ti plasmids. Examples 9 and 10 refer in general to the regeneration of plants from carrot and tobacco tumours, respectively, without any reference to any foreign gene expressed therein. Example 11 refers to the introduction of expressible phaseolin gene into regenerated alfalfa plants, but fails to report any actual experimental data. Example 12 is concerned in general with techniques for extracting, fractionating and detecting RNA. Example 13 refers to micro-ELISA assays for the detection of phaseolin. Finally, Example 14 describes in general the accomplishment of triparental matings.

11. Thus the actual technical contribution to the state of the art by the disclosure of the patent in suit essentially consists of providing experimental support for the transfer and expression into plant cells of a DNA sequence encoding phaseolin under the control of its own promoter. In other words, the technical contribution is not a new general technique for achieving expression of a plant structural gene in a plant cell, but the successful completion of the experiment anticipated by Dr Kemp in his oral disclosure by testing the effect of the transfer into plant cells of the known vector construct comprising the phaseolin gene including its own promoter regions (see point 9 above). Through reference to the prior art, the description indicates how plant regeneration can be obtained from these cells. The specific teachings of the examples are then generalised in the description, where it is stated: "The invention in principle applies to any introduction of plant genes into any plant species into which T-DNA can be introduced and in which T-DNA can remain stably replicated. In general these species include, but are not limited to, dicotyledonous plants..." (see page 8, lines 51 to 54). The description also indicates on page 9, lines 3 to 17, that the promoter and structural gene may be derived from the same or different plant sources, that a plant gene can be placed downstream either from its own promoter or from a different plant promoter and that the promoter and coding regions may also include modifications, either naturally or artificially induced, and may include chemically synthesised segments. However, no examples are given in this respect.

12. Claim 1 at issue is generally directed to a method for genetically modifying a plant cell by transferring into it a combination T-DNA/plant promoter-plant gene, such that expression of the protein encoded by the said plant structural gene is detectable in said plant cell (feature "such that..."). No specific details are given in the claim in respect of the structural arrangement of the combination T-DNA/plant promoter-plant gene, except for the self-evident indication that the plant promoter is adjacent to the 5'-end of the structural gene which is downstream from the promoter in the direction of transcription (see item (a)). Thus, the skilled person is essentially instructed by the claim to transfer a DNA vector such as the one disclosed in document (5a) (see point 9 above) into a plant cell "such that expression of the protein encoded by the said plant structural gene is detectable in said plant cell". Failing any limitations in respect of the kind of plant cell and/or plant gene and/or plant promoter, the claim is thus directed to a method whenever it works (see the feature "such that...") for a whole range of applications. In other words, the skilled person is told that patent protection is claimed whenever expression of any desired plant gene is detected upon transfer of the said gene with its own promoter or any other plant promoter into any plant cell via a T-DNA vector in a manner known in the art.

13. Formal support for this broadly formulated claim can indeed be found in the general statements in the description (see point 11 above). However, the question is whether the skilled person, on the basis of the description of the patent in suit (see point 10 above) and of the prior art, would have been in a position at the priority date to carry out the method for the whole range of applications claimed without finding himself/herself in a situation where, despite using reasonable effort to make the method work, he or she would not have achieved the technical effect for some applications or would have achieved it only with undue burden.

14. The present case is a delicately balanced one because:

- If it is maintained that the achievement of the technical effect (expression) is the inevitable result of the technical measure of placing a plant structural gene into a T-DNA vector adjacent and downstream from a plant promoter, then substantiation by way of one example could be considered sufficient, but there would indeed be little merit in such a proposition because this measure had already been anticipated in explicit, though predictive terms by document (5a);

- If, however, it can be inferred that the achievement of the technical effect is by no means certain, especially when working in areas of application other than the one given by way of example, and possibly requires more work than the simple placing of a plant structural gene downstream from a plant promoter, then, although merit could possibly be seen in the specific achievement concerned, more technical details would be required to support a claim to the whole range of envisaged applications.

15. The board notes that, in their arguments in favour of inventive step (see section X above), the respondents submitted that major research was needed in order to test whether the vector construction disclosed in document (5a) was capable of bringing about expression of phaseolin. If this is accepted to be the case notwithstanding the explicit indications already provided in document (5a), then there must be serious doubts as to whether the mere completion of the experiment announced by Dr Kemp, this being the actual contribution to the state of the art by the patent in suit (see point 11 above), can give the proper technical support to a claim with such a wide range of applications as present claim 1. This is because it can reasonably be expected that the skilled person would face similar difficulties when trying to obtain the same technical effect with the whole range of different combinations of plant structural gene/plant promoter claimed. In fact, these comprise not simply suitable variants of the exemplified component features, eg variant forms of the phaseolin gene and/or phaseolin promoter, but also a wealth of structurally and functionally different entities, eg plant structural genes encoding a protein other than phaseolin or promoters other than the phaseolin promoter, or technical situations, eg monocotyledonous or other dicotyledonous plants, in respect of which difficulties and uncertainties in achieving the claimed technical effect still remain, in spite of the reported specific example of phaseolin with its own promoter. Confirmation of the fact that success can be achieved with phaseolin with its own promoter is not necessarily of any help to the skilled person trying to obtain the same effect with totally different plant gene/promoter combinations.

16. The above considerations find support in some later evidence on file. For example, document (36) shows that, upon transfer via T-DNA into sunflower cells (dicotyledonous plant cells) of a monocotyledonous gene (maize zein) containing sufficient information within the 5' flanking regions to direct transcription, no protein was detected, notwithstanding the presence of mRNA (see in particular page 379, last paragraph, and page 380). Also document (38), published shortly after the present priority date, reports that attempts to express, for example, a plant gene encoding leghaemoglobin into tobacco cells via Ti-plasmid gene vectors were unsuccessful, presumably due to the lack of recognition of the transcription signals (promoter sequences) (see, in particular, page 209, last paragraph).

17. In a technically similar case relating to a patent with generic claims directed to a method for incorporating foreign DNA into the genome of monocotyledonous plants via a T-DNA, the then competent board of appeal decided that the requirements of Article 83 were not fulfilled because there were serious doubts as to whether such a method could be performed over the whole range that was claimed, namely with any monocotyledonous plant (see T 612/92 above).

18. In summary, the following observations can be made:

(a) the art of genetically modifying plant cells so as to achieve detectable levels of expression of a transferred foreign gene was not very well established at the priority date of the patent in suit and was faced with a number of uncertainties and problems such as stability of alien DNA into T-DNA and into the plant genome, presence of introns, stability of the proteins, effects of regulatory controls, etc. (see document (5a), in particular page 1);

(b) While confirming the validity of the technical indications given in document (5a), the patent in suit, by providing the single example of successful expression of phaseolin in plant cells following transfer via T-DNA of a phaseolin coding DNA with its own promoter, did not generally remove the problems and uncertainties mentioned under (a) above. The patent in suit did not make it plausible that the same effect would be obtained routinely in any plant cell by operating in an analogous manner with any combination of any plant structural gene with any plant promoter. In fact, the specification of the patent in suit leaves to the skilled person the whole burden of finding out and testing how and whether the transfer of any such combination into a plant cell is such that expression of the protein encoded by the plant structural gene is detectable in said plant cell. Under these circumstances, the feature "such that..." in claim 1 is seen as being not more than an invitation to perform a research programme in order to find the combinations which, if successful, are stated by the claim to fall under its scope (see T 435/91 above, in particular point 2.2.1 of the Reasons);

(c) later publications (see point 16 above) indeed show that the transfer of foreign DNA via T-DNA into some classes of plants, eg monocotyledonous plants, as well as the expression of the transferred gene under its own signals, were largely empirical and thus involved a large amount of trial and error with a high risk of failure.

19. In view of the above considerations, the board has decided that the experimental evidence and technical details in the description of the patent in suit are not sufficient for the skilled person to reliably achieve without undue burden the technical effect of expression in any plant cell of any plant structural gene under the control of any plant promoter and that, consequently, they do not provide sufficient support for a claim, such as present claim 1, broadly directed to such a method.

20. For these reasons the main request, of which claim 1 is part, is refused under the provisions of Articles 83 and 84 EPC.

First auxiliary request

21. Compared with claim 10 as granted, claim 1 of this request, apart from the feature "such that..." (see point 2 above), contains a limitation of the method to the modification of a dicotyledonous plant cell by transfer of a dicotyledonous plant promoter with a dicotyledonous plant structural gene. In the board's judgment, this amendment narrows the scope of protection conferred in comparison with the claims as granted so that no objection under Article 123(3) EPC arises. Moreover, in the board's view, the basis for this amendment can be derived from page 15 of the application as filed, where specific reference is made to any introduction of plant genes into any plant species, including dicotyledonous plants, in combination with the passage starting on page 15 and continuing on page 16 of the description, where the definition of a plant gene is given. Thus, the amendment in question does not result in the creation of subject-matter extending beyond the content of the application as filed and, consequently, no objection under Article 123(2) EPC arises.

22. The limitation of claim 1 of this request to a dicotyledonous plant cell into which a dicotyledonous plant promoter with a dicotyledonous plant structural gene is transferred does not remove the objections under Articles 83 and 84 raised in respect of the subject-matter of claim 1 of the main request because, for the same reasons as given above (see points 3 to 19), the description of the way expression at detectable levels was achieved in respect of the phaseolin gene with its own promoter does not allow the skilled person to perform the invention without undue burden within the whole area claimed, ie to genetically modify any dicotyledonous plant cell by inserting into it any dicotyledonous plant structural gene under the control of any dicotyledonous plant promoter.

23. For these reasons the first auxiliary request has also to be refused under the provisions of Articles 83 and 84 EPC.

Second auxiliary request

Third auxiliary request

25. Compared with claim 10 as granted, claim 1 of this request, apart from the feature "such that..." (see point 2 above), contains a limitation of the method to the modification of a dicotyledonous plant cell by transfer of a phaseolin promoter with a phaseolin structural gene. By way of this amendment the scope of protection is narrowed over the claims as granted so that no objection under Article 123(3) EPC arises. The combination of the phaseolin structural gene with its own promoter is disclosed in the examples of the application as filed (see Example 1). This application also refers on page 13 to the homology of the molecular species of phaseolin and on page 16 to the naturally or artificially induced modifications of the promoter and/or coding regions of plant genes. This constitutes direct and unambiguous support not only for the combination of a specific phaseolin structural gene with its own promoter, but also for various combinations of variant forms of both. For these reasons it is considered that the amendments in question do not result in the creation of subject-matter extending beyond the content of the application as filed and, consequently, that no objection under Article 123(2) EPC arises.

26. The limitation of claim 1 of this request to a dicotyledonous plant cell into which a phaseolin promoter with a phaseolin structural gene is transferred brings the subject-matter of this cla im into compliance with the requirements of Articles 83 and 84 EPC. In fact, the description of how expression at detectable levels was achieved in respect of the phaseolin gene with its own promoter provides the skilled person with sufficient guidance for performing the invention as claimed in claim 1 without undue burden and for reliably obtaining the same technical effect, including when suitable variants of the component features concerned are used (eg variant forms of the phaseolin gene or phaseolin promoter) (see T 292/85, above; see point 5 above). The board considers that, unlike the case with genes and promoters other than phaseolin, the technical circumstances in the case of variants of the phaseolin gene and promoter are so similar that it is plausible that the claimed invention can be put into practice routinely within this framework. In the light of the contribution to the state of the art by the patent in suit, this is considered by the board to be a fair generalisation.

27. In his oral disclosure, Dr J.D. Kemp (see document (5a)), while making reference to the construction of a DNA vector comprising T-DNA having inserted into it "the entire phaseolin gene including its own promoter regions" (see page 4, lines 7 to 8; compare with feature (a) in claim 1), stated that he could not report on the final experiment because this had not yet been completed (see page 4, lines 3 to 4). Thus, the transfer of said DNA vector construct into a dicotyledonous plant cell and/or the tests of the level of expression of the protein encoded by the inserted plant gene (see feature (b) in claim 1) were not disclosed by Dr Kemp. In the board's judgment, these cannot be considered to be an implicit part of his disclosure as inevitably derivable from the description of the DNA vector. In fact, failing any further details and reports of experimental data, the skilled person at the priority date was not in a position to inevitably derive from document (5a) the technical effect produced by the DNA vector in a dicotyledonous plant cell, in view of the many uncertainties and problems of this technical area. Thus the difference between the statements in document (5a) and the claimed subject-matter is not merely in the wording, but in the technical teaching. For these reasons the subject-matter of claims 1 to 7 of the present request is novel having regard to document (5a). Novelty over the other documents on file is undisputed.

28. Inventive step (Article 56 EPC)

28.1 Document (5a) represents the closest prior art for the claims at issue. Its contents have already been discussed under point 9 above.

28.2 In the light of this document, the technical problem to be solved is the achievement of detectable levels of expression of phaseolin in a dicotyledonous plant cell.

28.3 The claims under discussion are intended to solve this problem by measuring the level of expression of phaseolin in a dicotyledonous plant cell after transfer thereto of a T-DNA/plant gene combinati on wherein a plant gene comprising a phaseolin promoter and a phaseolin structural gene is inserted into T-DNA, the plant promoter being adjacent to the 5'-end of the plant structural gene and the plant structural gene being downstream from the plant promoter in the direction of transcription. The latter is in fact a DNA vector construct such as the one known from document (5a) so that it can be said that the proposed solution consists in the measurement of the level of expression of phaseolin in a dicotyledonous plant cell after transfer thereto of the DNA vector known from document (5a).

28.4 In view of the examples disclosed in the patent in suit, in particular Examples 1 and 2, the board is satisfied that the above-stated technical problem has been solved since it has been shown that detectable levels of phaseolin are measured in sunflower plant cells when the proposed method is applied.

28.5 The relevant question in respect of inventive step is whether the skilled person, starting from the oral disclosure of Dr Kemp (document (5a)), would have carried out the experiment referred to in it with a reasonable expectation of success. In this respect, the statement in decision T 296/93 (above) that "a reasonable expectation of success" should not be confused with the understandable "hope to succeed" (see loc.cit., point 7.4.4 of the Reasons) is of relevance. In fact, while it can be said that, in the light of document (5a), the experiment in question was "obvious to try" for the skilled person, it is not necessarily true that this person would have had any reasonable expectation of success when embarking on it. The announcement by Dr Kemp that such an experiment was in progress in his laboratory was not in itself a guarantee in this respect, especially in view of the warning given by the same Dr Kemp that "... this has been done by a number of people now and nobody has shown a functional gene when one includes the endogenous promoter". Thus, the outcome of the said experiment was still uncertain. The question to be decided is therefore whether the average skilled person was in a position to reasonably predict its successful conclusion, on the basis of the existing knowledge, before starting the experiment.

28.6 As stated above (see point 18, item (a)), in early 1983 the art of genetically modifying plant cells so as to achieve detectable levels of expression of a transferred foreign gene was not yet routinely established. Although some success had been reported in respect of T-DNA vector constructs where the foreign gene was placed under the control of Ti promoters (see, for example, documents (9a) and (31)), the skilled person still faced a number of uncertainties and problems, such as stability of alien DNA into T-DNA and into the plant genome, presence of introns, stability of the proteins, effects of regulatory controls, etc. (see document (5a), in particular page 1). This should be taken into account when making an objective analysis of the degree of confidence of the skilled person on the priority date that he or she would have succeeded in solving the underlying technical problem by embarking on the experiment referred to by Dr Kemp.

28.7 When trying to make a reasonable prediction of the prospects of success for the experiment indicated in document (5a), the skilled person would have had to have taken the following facts into account:

(a) the uncertainties and difficulties of the technical field (see point 28.6 above);

(b) while there were reports of expression in a plant cell of a foreign gene inserted into T-DNA downstream from Ti regulatory sequences (see documents (9a) and (31)), there were no positive reports of functional genes when the endogenous promoter was included (see document (5a));

(c) although from a theoretical point of view it was conceivable that a plant promoter could be recognised by the plant transcription machinery, no prediction could have been made as to whether it would be actually recognised when placed into a T-DNA (see item (b) above). Moreover, in view of the highly specialised nature and regulation of the phaseolin promoter - a seed promoter - (see the general background information as reported on page 8, lines 5 to 20, of the patent specification), it was difficult to predict whether it would operate in dicotyledonous plant tissues other than the seed;

(d) although the isolation and partial nucleotide sequence of a phaseolin genomic clone containing the entire gene together with extensive sequences flanking its 3' and 5' ends and of a cloned cDNA had been reported (see document (49)), the expression of phaseolin in a recombinant organism had not yet been disclosed. An indirect report in the literature (see document (3), in particular page 266, left-hand column, fifth paragraph) referred to an experiment in which, using Agrobacterium with a gene of unspecified structure coding for phaseolin inserted into its T-DNA, transcription of bean globulin mRNA in tissue cultures from sunflower tumours had been obtained, but not its translation.

28.8 All the above factors and considerations would have negatively influenced the degree of confidence of the skilled person in the successful outcome of the experiment referred to in document (5a). He or she would therefore not have reasonably expected that expression of detectable levels of phaseolin in a dicotyledonous plant cell would be easily achievable and, owing to this, would have received the results of the patent in suit with some surprise.

28.9 For these reasons the board concludes that the subject-matter of claim 1 of the request at issue involves an inventive step (Article 56 EPC). The same applies to claims 2 to 6 of this request, which represent embodiments of the invention as claimed in claim 1, as well as to the subject-matter of claim 7, ie the plant cell produced according to the method of claims 1 to 6.

Conclusion

29. From the above it follows that the patent in suit can be maintained on the basis of claims 1 to 7 of the third auxiliary request.