T 0558/03 (Wild-type p53 gene/JOHNS HOPKINS UNIVERSITY) 02-06-2005

Reasons for the Decision

Admissibility of Appellants' requests (Article 114(2) EPC)

1. To expedite the proceedings, parties are supposed to submit all facts, evidence and requests at the outset of appeal proceedings, or - if this is not possible - as soon as they can. The Board has to ensure that proceedings are conducted expeditiously, and the parties fairly treated, e.g. not taken by surprise by what is called a "new case" filed at a late phase of the proceedings (cf Case Law of the Boards of Appeal of the European Patent Office, Chapter VI.F, 4th edition, 2001).

2. The Board agrees with the Respondents that Appellants' final requests have been filed at a very late stage of the proceedings as they were received by fax on 27 May 2005, thus within one week before the oral proceedings held on 2 June 2005.

However, as stated in sections (V) and (VI) above, claim 1 of Appellants' new main request and auxiliary requests I and II was identically contained in the main request before the Opposition Division (and is identical to claim 1 as granted). Claim 23 of the new main request and of auxiliary requests I to III was identically contained in the main request before the Opposition Division.

3. These are claims at issue (see reasons). Therefore, the Board, at its discretion under Article 114(1) EPC, and considering that the above stated facts do not result in an unfair treatment of the Respondents, allows these requests into the procedure.

4. In claim 1 of auxiliary request IV, and in all other independent claim of this request, the sequence of the wild-type p53 gene has been characterised as being identical to the sequence disclosed in document (21).

This amendment has been carried out in reaction to the decision of the Opposition Division, which in point (7.3) of the decision under appeal found that a claim generally referring to a "wild-type p53 gene" violates the requirements of Article 83 EPC. After the Board, in point (8) of their communication of 6 December 2004, have signalized the parties that they tend to share the Opposition Division's point of view in this respect, the Appellants on 1 April 2005, thus within the time limit set by the Board for making written submissions, which was set at two months before the oral proceedings, filed a new auxiliary request V (which corresponds to the present auxiliary request IV).

The Board judges that the Appellants, by filing auxiliary request IV at a late stage of the procedure, have nonetheless not abused the procedure as they acted as soon as they became aware that the Board is of the preliminary opinion that the Opposition Division decided correctly.

Auxiliary request IV is therefore allowed into the proceedings.

Main Request

Sufficiency of disclosure (Article 83 EPC)

5. Claim 1 refers to a diagnostic method based on the analyses of the p53 gene sequence in the cells of a tissue sample and on the comparison of the detected sequence with wild type p53 genes.

Claim 23 relates to a method of supplying human wild- type p53 gene function to a human cell having lost said function, comprising introducing in vitro a wild-type p53 gene into the cell such that said gene is expressed in the cell.

The p53 gene codes for protein p53, which is described in the art as being a "tumour suppressor protein" (document (51), abstract). Loss of wild-type p53 genes or their expression products indicates neoplasia of a tissue.

In order to be able to evaluate the results of the methods of claims 1 and 23 the skilled practitioner must be in possession of the wild-type p53 gene sequence.

6. The patent does not explicitly disclose what a wild- type p53 gene is. Instead of this it refers on page 6 lines 16 to 20 (corresponding to column 10, line 55 to column 11, line 8 of the application as originally filed) to five prior art documents which allegedly disclose human wild type p53 genes. This passage reads:

"First, p53 cDNA probes detecting exons spread over 20,000base pairs (including all protein encoding exons) [P. Lamb, L.V.Crawford, Mol. Cell. Biol. 6, 1379 (1986); R. Zakut-Houri, B.Bienz-Tadmor, D. Givol, M. Oren, EMBO J. 4, 1251(1985); N. Harris E.Brill, O. Shahat, M. Prokocimer, T.E. Admas, Mol. Cell. Biol., 6, 4650(1986); G. Matlashewski et al., Molec. Cell. Biol. 7, 961 (1987); V.L.Buchman et al., Gene 70, 245 (1988)] were used to examine the DNA of 82 colorectal carcinomas (50 primary specimens and 32 cell lines)in Southern blotting experiments."

The reference to these five publications, documents (16), (21), (22), (23) and (24) in the present procedure, is repeated on page 7, lines 23 to 24 (column 13, lines 21 to 23 as filed).

7. Document (16) discloses in figure (2) on page 1381, the DNA sequence of the human p53 gene and the predicted amino acid sequence of the protein. Differences between this sequence and human p53 cDNA are indicated. The figure shows three sequences, a "main sequence", and two sequences containing changes in one single nucleotide. In the first case a change from CGC to CCC results in change at codon 72 from Arginine to Proline (R72P), in the second case a change from CGT to CAT at codon 273 results in a change from Arginine to Histidine (R273H). The "main sequence" is also disclosed in documents (22), (23) and (24). R72P is also disclosed in documents (21), (22), (23) and (24). Document (23) additionally refers to a sequence containing Cystein at position 72, document (22) discloses a sequence with Threonine instead of Alanine at position 79.

Thus, the five documents disclose five different sequences which all are disclosed to represent a human wild-type p53 sequence.

8. Document (52), published eight months after the claimed priority date and naming three of the present inventors as authors, discloses for the first time that one of the p53 sequences published in document (16), namely R273H, in fact is not a wild-type sequence but a tumorigenic mutation (see page 705, right column, third full paragraph). The same information is conveyed in document (25), published five years after the priority date (see table 1 on page 3965).

9. The consequences of this post-published disclosure are as follows:

The patent in suit does not disclose the decisive technical feature which is necessary for a skilled person to carry out the claimed invention, namely the correct sequence of human wild-type p53 genes.

A skilled reader practising the invention according to claim 1, after having sequenced the p53 gene contained in the cells of the sample, will compare the detected sequence with the five sequences disclosed in documents (16) and (21) to (24). If the sequence turns out to be identical to one of the five sequences which are defined in the patent as being wild-type p53 sequences, the result of the diagnostic test will be classified as negative, which means that the tissue sample does not contain neoplastic tissue. If, however, the detected sequence is identical to the R273H sequence disclosed in document (16), which has turned out to be a tumorigenic mutation, this result would wrongly be classified as negative.

As a result neoplastic tissue of a human patient would be misjudged as being not neoplastic. Besides the fact that this shortcoming of the method according to claim 1 manifests a violation of the requirements of Article 83 EPC, it has the undesirable implication that a wrong negative result in terms of the diagnosis of tumours might have potentially disastrous effects for the human patient concerned.

When trying to supply human wild-type gene p53 function to a cell, according to claim 23, introduction of the R273H mutant into the cell will not result in a reactivation of the wild-type function.

10. The Appellants argue that a skilled person reading the patent in suit is provided with information encouraging him/her to test if the sequences disclosed in the cited prior art documents really are wild-type sequences. These tests allow him/her to find out that this is not the case for the R273H sequence disclosed in document (16).

According to the Appellants a first test is described in column 8, lines 24 to 52 of the application as filed, where it is said that the introduction and expression of a wild-type p53 gene in a cell carrying a mutant p53 allele results in non-neoplastic growth of the cell. Thus, by monitoring the desired effect, e.g. non-neoplastic growth of the cell, one can determine whether the inserted gene was a wild-type p53 gene or not.

Another test, based on screening of loss of wild-type p53 protein function is said to be disclosed in column 6, lines 23 to 33 of the application as filed. Loss of ability of the p53 protein to bind to either of SV40 large T antigen or to the adenovirus E1B antigen indicates a mutational alteration of the protein which reflects a mutational alteration of the gene itself. Documents (50), published three years after the priority date (see page 4336, top of left column and first full paragraph, right column), and document (51), published four years after the priority date (see page 3817, right column, last paragraph) disclose that R273H does not bind to SV40 large T antigen.

Finally, the Appellants argue that example 5 (in columns 14 to 15 of the application as filed), discloses a test to ensure whether a sequence change represents a mutation rather than a polymorphism. This test comprises comparing the sequence containing the candidate mutation/ polymorphism obtained from a tumour of an individual with the p53 sequence obtained from normal cells of the same individual. If the sequence change is present in a normal cell it is a polymorphism, if not it is a mutation.

11. The Board does not agree that a lack of sufficient disclosure can be cured by a reference to these tests, which are not considered to put a skilled person into the position where he/she is able to carry out the invention as described in the specification and as defined in claims 1 and 23 without undue burden.

The specification, by reference to five prior art documents, discloses five sequences which are designated as wild type p53 gene sequences, and which a skilled person carrying out the methods claimed would use as reference sequences. At no point in the specification or in the claims, the skilled person is advised to carry out any of the tests identified in point (11) above to verify that the obtained results are correct. He/she would have no reason to carry out any further tests.

In case of the method of claim 1, the skilled person would not be aware that some of the negative results in fact were wrong negative results.

12. In addition, the tests specified by the Appellants and referred to in point (11) above partly are not considered to be conclusive, partly involve undue burden.

The introduction of a wild-type gene into a cell carrying a mutant allele, wherein the wild type gene either remains extrachromosomal or recombines with the endogenous mutant gene, as described in column 8 of the original application, is a laborious and time consuming undertaking. The observation whether or not in the present case the inserted gene is a wild-type gene depends on a number of circumstances. This is evident from the cautious language used in the relevant passage of the specification in column 8 ("..the wild-type p53 gene or gene portion should be expressed to a higher level than that of the mutant gene", or "...such recombination would require a double recombination event which would result in the correction of the p53 gene mutation." emphasis added by the Board).

The loss of ability of R273H to bind to the SV40 large T antigen is described in post published document (52) only in case of the entire protein. In contrast, fragments of this mutant protein expressed as fusion proteins in E.coli were found to bind the antigen (see document (52), table 1 and page 3817, right column, last paragraph).

Finally, the passage in example 5 of the patent, which the Appellants consider to disclose a generally applicable test for determining whether a sequence change represents a mutation rather than a sequence polymorphism, specifically refers to the assessment of a sequence change at codon 175 of the p53 gene. Moreover, a method relying on the comparison of the p53 gene in normal and tumorigenic tissue of the same individual, seems to be of little use, at least in a diagnostic or therapeutic context.

13. Following another line of argumentation, the Appellants by referring to decision T 292/85 (OJ EPO 1989, 275), argue that it is irrelevant that one of the sequences disclosed in document (16), namely R273H, cannot be used in the claimed methods as long as there are four other suitable sequences disclosed which represent the human wild-type p53 sequence.

The Board does not consider decision T 292/85 to be applicable in the present case as it is related to a different technical situation. Contrary to the present case, where one embodiment of the invention which is explicitly disclosed in the description, is not suitable to perform the invention, the Board, in decision T 292/85 held that the non-availability of some particular variants was immaterial as long as there were suitable variants which provided the same effect.

14. The patent in suit does not contain a reliable definition of the wild-type p53 gene, which would allow a skilled person to identify it. In fact one out of five sequences, disclosed in the patent by reference to prior art documents as being wild type sequences, later turned out to be a tumorigenic mutant.

Therefore, neither a diagnostic method comprising the detection of loss of wild-type p53 genes, according to claim 1, nor a method of supplying human wild-type p53 gene function to a cell which has lost said function, according to claim 23, are disclosed in the patent in a manner sufficiently clear and complete for it to be carried out by a skilled person.

The requirements of Article 83 EPC are not met.

Auxiliary Requests I and II

15. Claims 1 and 23 of these requests are identical to claim 1 of the main request. The decision taken with regard to the main request applies equally to auxiliary requests I and II.

Auxiliary Request III

16. Claim 1 of auxiliary request III is distinguished from claim 1 of the previous requests by insertion of the term "compared to normal tissue isolated of the human" (see section (VI) above).

A decision as to whether claim 1 of auxiliary request III meets the requirements of Article 83 EPC is not considered to be necessary in the present case. As claim 23 of this request is identical to claim 23 of the main request, the requirements of Article 83 EPC are not met for this reason alone.

Auxiliary Request IV

Amendments (Articles 123(2) and 123(3) EPC

17. In claim 1 of auxiliary request IV, and in all other independent claims of this request (either explicitly or by back-reference to claim 1), the wild-type p53 gene sequence is defined as being "...shown in Zakut- Houri et al., EMBO J., 4, 1251-1255, 1985."

This document, designated in the present procedure as document (21), discloses in figure 2 on page 1252 the nucleotide sequence and deduced amino acid sequence of the entire coding region of human p53 cDNA in comparison with mouse p53 cDNA. No other gene sequences are contained in the document. Document (21) is one out of the five documents which are cited in column 10, line 55 to column 11, line 8 and column 13, lines 21 to 23 of the originally filed application, as disclosing human wild-type p53 gene sequences (see point (6) above).

Probes generated from a fragment of the cDNA clone disclosed in document (21) were used in examples 3 (see passage bridging columns 11 and 12) and in example 4 (see passage bridging columns 13 and 14 of the application as filed).

18. The Respondents argued that features which are not disclosed in the description of the invention as originally filed but which are only described in a cross-referenced document which is identified in such description are prima facie not within "the content of the application as filed" for the purpose of Article 123(2) EPC. It is only under particular conditions that such features can be introduced by way of amendment into the claims of an application, which conditions were not met by the patent in suit. They referred in this respect to decision T 689/90 (OJ EPO 1993, 616).

19. Claim 1 of the patent underlying decision T 689/90 included the feature that "at least one of the locating member (11) and the return member (12) comprises a metal core and an elongate jacket which electrically surrounds the core and which is composed of a conductive polymer", which was not contained in the application as filed. The description as originally filed included the following sentence in particular which was said by the Applicant to provide a proper basis for the above feature: "For further details of suitable locating, source, and return members, reference should be made to the application corresponding to US Serial No. 509 897". The Board decided that features incorporated from the cited prior art document into claim 1 contravened Article 123(2) EPC (see point (4) of reasons for the decision).

The present situation, where the application as originally filed contains an explicit basis for the amendment, namely a statement that document (21) discloses a wild-type p53 sequence, is different. In contrast to the facts underlying decision T 689/90, where the original application did not disclose the precise features which later were incorporated into claim 1 by reference to a prior art document containing them, a precise and originally disclosed feature, namely the p53 sequence shown in figure 2 of document (21) has been introduced into claim 1 and other independent claims.

20. Moreover, the Respondents objected that neither example 2 nor example 4, where reference is made to document (21), refers to a method of diagnosis according to claim 1. As such diagnostic method is disclosed only in column 2 of the original application, under the heading "Summary of the Invention", where no reference to document (21) is made, the subject-matter of claim 1 violates Article 123(2) EPC.

The Board is convinced that the application as filed as a whole refers to diagnostic methods for detecting the loss of wild-type p53 genes, and therapeutic methods for supplying human wild-type p53 gene function to a cell. As acknowledged by the Board with regard to lack of sufficient disclosure of the main request and of auxiliary requests I to III (see above), and as agreed by the Respondents, the original application discloses five different sequences as being wild-type p53 sequences. One thereof is the sequence referred to in the independent claims of auxiliary request IV. The introduction of this sequence into the claims by reference to document (21) does not therefore contravene the requirements of Article 123(2) EPC.

21. By defining the wild-type p53 gene sequence in the claims as corresponding to the sequence disclosed in document (21) the patent has not been amended in such a way as to extend the protection conferred (Article 123(3) EPC.

Clarity (Article 84 EPC)

22. The Respondents referred to decision T 11/89 of 6. December 1990 and argued that according to the case law of the Boards of Appeal a reference to a prior art document is not a technical feature and is not appropriate for determining the scope of a claim. Therefore, claim 1, which is not clear by itself, but only when read in combination with document (21), violates the requirements of Article 84 EPC.

23. Decision T 11/89 is concerned with a patent application referring to a group of chemical compounds defined in claim 1 by a formula (I). The claim comprises a disclaimer reading: "...mit Ausnahme der in der EP-A-0 133 530 offenbarten Naphtyridinon-Derivate der allgemeinen Formel I."

Thus the reference to a prior art document is used to disclaim a not precisely defined group of compounds disclosed therein. The competent Board found that a disclaimer formulated in this way does not allow to clearly define the scope of the claim which therefore violated Article 84 EPC.

24. This is different from the present situation, where the skilled reader has no difficulty to define the scope of the claim. Claim 1 refers to a diagnostic test which requires knowledge of the wild type p53 gene sequence. This sequence is defined as being identical to the sequence shown in document (21).

25. Moreover, the Respondents objected that claim 1 refers to "the wild-type p53 gene sequence" shown in document (21) while the cited document discloses in Figure 2 the human and mouse p53 cDNAs. Claim 1 lacks clarity, firstly because a cDNA is a different entity than a genomic DNA, and secondly because document (21) discloses more than one sequence.

26. When considering a claim, one should rule out interpretations which are illogical or which do not make technical sense. One should try to arrive at an interpretation of the claim which is technically sensible and takes into account the whole disclosure of the patent (Article 69 EPC). The claim must be construed by a mind willing to understand not a mind desirous of misunderstanding (cf decision T 396/99 of 19. November 2001, ultimate paragraph of section 3.5).

27. Claim 1 refers to a diagnostic method practised on an isolated human tissue sample comprising the detection of loss of wild type p53 genes. Use of mouse DNA as reference sequence would not make technical sense.

28. The claim refers to "the wild type p53 gene sequence" shown in document (21). The Board, while being aware of the difference between a cDNA sequence and a genomic DNA sequence, takes the view that it is clear to a skilled person willing to understand claim 1, that this term defines the human sequence shown in Figure 2 of document (21), as in the contextual meaning of the language as used in the technical field concerned, the term "gene sequence" is not normally used to define an entire gene but rather the protein encoding exons thereof. The description of the application as filed, column 10, lines 55 to 57 reads: "First, p53 cDNA probes detecting exons spread over 20,000 base pairs (including all protein encoding exons)...". This passage is immediately followed by the citation of, among others, document (21).

29. In consequence, the Board is convinced that the claims of auxiliary request IV meet the requirements of Article 84 EPC.

Patentable inventions (Article 52(4) EPC)

30. None of the claims refers to a diagnostic or therapeutic method practised on the human or animal body, which are not regarded as patentable inventions according to Article 52(4) EPC.

Sufficiency of disclosure (Article 83 EPC)

31. The Respondents argued that the diagnostic method according to claim 1 is not sufficiently disclosed. The method relies on the analyses of the p53 gene sequence in a cell of a tissue sample and the determination whether or not this sequence is identical to the p53 gene sequence disclosed in document (21). Such method will give rise to a large number of wrong positive results, as the wild-type sequence shown in document (21) is only one of a number of human wild-type sequences, others being for instance disclosed in documents (16), (22) and (23). Therefore, many samples containing one of this other p53 wild-type sequences will wrongly be considered to contain neoplastic tissue.

32. The Board does not share the Respondents' view. Claim 1 refers to a method comprising the comparison of the p53 gene contained in a tissue sample with a defined reference sequence, namely the p53 wild-type sequence shown in document (21). Thus, the patent contains sufficient information allowing a skilled person to carry out the claimed method according to the requirements of Article 83 EPC.

The same applies to claims referring to a method for supplying human wild-type p53 gene function to a cell have lost this function, by introducing into the cell in vitro a gene having the sequence shown in document (21).

The point raised by the Respondents, namely if a method according to claim 1 reliably can be used for the diagnosis of a neoplastic tissue (see point (31) above), refers to the question if the problem underlying the patent is solved. This does not have to be considered under Article 83 EPC but under Article 56 EPC.

Inventive step (Article 56 EPC)

Remittal to the first instance (Article 111(1) EPC)

33. The Board, as a consequence of the substantial amendments to the claims according to auxiliary request IV, proposed in the appeal procedure, has decided that this request meets the requirements of Articles 52(4), 83, 84, 123(2) and 123(3) EPC.

Examination of inventive step has not been carried out by the Opposition Division, as all requests before them were found not to meet the requirements of the EPC for other reasons (see section IV above).

In the present case, in the light of the substantive amendments made to the claims, the Board considers it justified and appropriate to have this issue examined by two instances.

Thus, the Board at its discretion under Article 111(1) EPC remits the case to the Opposition Division for further prosecution.