T 1049/10 (Nucleosides/DAIICHI SANKYO) 27-03-2014

1. The appeal is admissible

Main request

2. Admission of this request

2.1 According to Article 13(1) of the Rules of Procedure of the Boards of Appeal (RPBA), the admission of any amendments of the appellant's case after it has filed its grounds for appeal is within the discretion of the board. This discretion "shall be exercised in view of inter alia the complexity of the new subject-matter submitted, the current state of the proceedings and the need for procedural economy" (see OJ EPO Supplementary publication 1/2014, pages 44-53).

2.2 The claims of the main request differ from those of auxiliary request 1 submitted with the grounds of appeal only in that "having at least one substituent" was replaced by "having a substituent" in the definition of the radical B in claim 1 and 10. The respondents have not argued that this amendment was complex, nor does the board have reason to consider it to be so.

2.3 This amendment is a reaction to the communication dated 10 January 2014 in which the board raised for the first time the preliminary objection that the replacement of "having a substituent" in the application as filed by "having at least one substituent" might add subject-matter extending beyond the content of the application as filed (see points 5.2 and 5.3 of said communication). So, the amended request could reasonably be expected to be filed only at a late stage of the proceedings. Even if the appellant could have filed the request prior to the oral proceedings of 27 March 2014, the respondents could deduce from said communication that the feature "having at last one substituent ..." might be amended, most probably by way of reverting to the wording of the application as filed, i.e. to "having a substituent ...", which was indeed the case. Hence, the respondents should have been prepared to discuss the claims of the main request and were not disadvantaged by the time of filing of the main request. Moreover, consideration of the main request did not delay the proceedings.

2.4 For these reasons the board decided to admit the claims of the main request into the proceedings.

3. Article 123(3) and Rule 80 EPC

3.1 The appellant has amended claim 4 by replacing the expression

"a methyl group substituted by from 1 to 3 aryl groups the aryl ring of which is substituted by an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, halogen or cyano group"

in claim 4 as granted by

"a methylbenzyl, 2,4,6-trimethylbenzyl, 3,4,5-trimethylbenzyl, 4-methoxy-benzyl, 4-methoxy-phenyldiphenylmethyl, 4,4'-dimethoxytriphenylmethyl, 2-nitrobenzyl, 4-nitrobenzyl, 4-chlorobenzyl, 4-bromobenzyl, 4-cyanobenzyl group".

3.2 The objections of the respondents were directed against the introduction of "2-nitrobenzyl, 4-nitrobenzyl" as possible meanings of the substituent R**(2).

3.3 Rule 80 EPC

In the decision under appeal, the then pending main request (based on the claims as granted) was rejected as claim 4 contravened the requirements of Article 123(2) EPC, i.e. because grounds under Article 100(c) EPC prejudiced the maintenance of the patent as granted (see point 5 of the reasons). The replacement of the objected amendment by the definition set out on page 5, lines 16-20, of the application as filed in claim 4 of the present main request sought to overcome this objection. Hence, this amendment as a whole was occasioned by a ground for opposition.

The fact that amended claim 1 now lists "2-nitrobenzyl, 4-nitrobenzyl" among the meanings of the substituent R**(2) is not relevant in this respect. Rule 80 EPC requires that the amendment is occasioned by a ground for opposition, not that this amendment is necessary to overcome a respective objection. Moreover, the appellant's argument makes sense in that the insertion of only those substituents listed on page 5, lines 16-20, of the application as filed which are not 2- or 4-nitrobenzyl into the claim might have given rise to an objection under Article 123(2) EPC.

3.4 Article 123(3) EPC

Each of the parties to the proceedings bears separately the burden of proof for the facts it alleges. The respondents alleged that the 2-nitrobenzyl and 4-nitrobenzyl groups could not be considered as hydroxyl protecting groups R**(2) as defined in claim 1 as granted. The respondents did not provide any evidence in support of this fact, nor does the board see any reasons why these nitrobenzyl groups should not act as hydroxyl protecting groups.

3.5 For these reasons, the board decided that claim 4 does not contravene the requirements of Article 123(3) and Rule 80 EPC.

4. Novelty

4.1 The respondents' objection as to novelty was based solely on document (D2). It was disputed whether this document disclosed directly and unambiguously compounds of formula (1) of present claim 1 in which the radical A means "an alkyl group having from 1 to 4 carbon atoms" (see point IV above).

The respondents relied on page 41, lines 10-29, of document (D2), where the following general formula IIa is depicted:

FORMULA/TABLE/GRAPHIC

where

B designates a nucleobase, preferably a nucleobase selected from thymine, cytosine, uracil, adenine and guanine (in particular adenine and guanine),

X is -O-,

R**(2*) and R**(4*) together designate a biradical selected from -(CH2)0-1-O-(CH2)1-3-, -(CH2)0-1-S-(CH2)1-3-, and

-(CH2)0-1-N(R**(N))-(CH2)1-3-, in particular -O-CH2-, -S-CH2- and -R**(N)-CH2-, where R**(N) is selected from hydrogen and

C1-4-alkyl.

The respondents argued that the general formula

-(CH2)0-1-O-(CH2)1-3-

covered six individual biradicals, including those of the formulae

-O-(CH2)2- and -O-(CH2)3-, i.e. compounds of present claim 1 wherein A is -(CH2)- or -(CH2)2-. Hence, the compounds of the formula of present claim 1 overlapped with those of formula IIa disclosed in document (D2).

4.2 The respondents deduced from decisions T 12/90, T 666/89 and T 124/87 that such an overlap deprived the claimed subject-matter of novelty; the person skilled in the art would have seriously contemplated working in the region of overlap as document (D2) generally discloses in Figures 2 and 24 the bridging of two carbon atoms of the furanose ring by a group of the formula -O-(CH2)2-.

4.3 The board agrees with the respondents in that the disclosure of a prior-art document is not limited to what is disclosed in the examples. On the other hand, there is no reason to disregard the examples when determining the information the skilled person extracts from such a document. This is in accordance with

- T 12/90 (where compounds 23 and 24 were taken into account; see the second paragraph of point 2.5 of the reasons); and

- T 666/89 (which considered experiments 1 and 4 to 9, see OJ EPO 8/1993, the second paragraph on page 500).

Document (D2) discloses in Figures 2 and 24 the bridging of the carbon atoms at positions 3 and 4 of the furanose ring (counting from the oxygen atom in the ring as position 1) by a group of the formula -O-(CH2)2- (see the general formulae V and X on page 3/44 and compounds 6 to 8 on page 27/44 of the drawings).

However, document (D2) discloses the bridging of positions 3 and 5 of the furanose ring only with biradicals of the formulae -O-(CH2)-, -S-(CH2)- and

-N(R**(N))-(CH2)- (see the following formulae depicted in the pages of the drawings:

- formula Q on page 2/44,

- formulae Z on page 3/44,

- formulae 36-39 on page 30/44,

- formulae 43-46 on page 31/44,

- formulae 50-53 on page 32/44,

- formulae 57-57D on page 33/44,

- formulae 61-61C on page 34/44,

- formula 44 on page 35/44,

- formulae 64-66 on page 36/44,

- formulae 71 and 61b on page 37/44,

- formulae 73-74A and Monomer Z**(TNH) on page 38/44,

- the formulae on page 39/44,

- formulae 76, 76C-76F and Monomer Z**(US) on page 40/44,

- formula 36 on page 41/44,

- formulae 202 and 203 on page 42/44,

- the formulae on page 43/44 and

- formulae 212-214, 36 and 37 on page 44/44).

This gives the overall impression that document (D2) discloses compounds having a group of the formula

-O-(CH2)2- bridging positions 3 and 4, but only those of the formulae -O-(CH2)-, -S-(CH2)- and

-N(R**(N))-(CH2)- bridging positions 3 and 5 at the furanose ring. Moreover, it makes sense to have different bridging groups at these positions as the chemical environments and reactivities at positions 4 and 5 on the furanose ring are quite different.

Decision T 124/87 cited by the respondents deals with quite a different situation, namely with the lack of novelty due to the overlap of the values of numerical ranges for two parameters (i.e. the density and the melt index of a copolymer). Hence, T 124/87 is not relevant for the present decision.

Therefore, the person skilled in the art would not have considered the subject-matter of the present claims as a direct and unambiguous disclosure of document (D2). The parties did not consider any other cited document to be relevant as to novelty, nor has the board reason to do so.

Hence, the subject-matter of the present claims is novel.

5. Clarity of the claims

5.1 The respondent saw an inconsistency between claims 1 and 7. Claim 7 lists radicals B which have one or more substituents on the purine ring system or on the pyrimidine ring; claim 1 refers to substituted purine or pyrimidine radicals B "having a substituent" selected from a certain group.

Whereas the respondents argued that the term "having a substituent" limited the number of substituents to one, the appellant was of the opinion that it permitted the radical B to have more than one substituent.

5.2 When assessing whether the term "having a substituent" renders the claim unclear, said term has to be interpreted in the context of the wording of the claims.

Said term forms part of the definition of the radical B in claims 1 and 10, which reads as follows:

"B represents a purin-9-yl group, a 2-oxo-pyrimidin-1-yl group or a substituted purin-9-yl group or a substituted 2-oxo-pyrimidin-1-yl group having a substituent selected from the following alpha group;

or a salt thereof; ...".

Hence, the term "having a substituent" refers "a substituted purin-9-yl group or a substituted 2-oxo-pyrimidin-1-yl group". The expressions "substituted purin-9-yl group" and "substituted 2-oxo-pyrimidin-1-yl group" clearly include such groups having more than one substituent. In this context, the term "having a substituent" cannot mean "having only one substituent" but allows for more substituents, as the board outlined during the oral proceedings.

Consequently, the alleged inconsistency of claim 1 with claim 7 (which mentioned such groups having more than one substituent) and within claim 1 does not exist.

5.3 A lack of clarity is no ground for opposition under Article 100 EPC. In opposition appeal proceedings, clarity is therefore assessed only to the extent that it is caused by amendments to the claims as granted.

Whether claims 1 and 10 permit other substituents to be present in the radical B than those of the group alpha does not have to be decided by the board; this alleged lack of clarity was already present in the claims as granted.

5.4 Hence, no lack of clarity prejudices the maintenance of the patent on the basis of the main request.

6. Request to decide on the admission of the auxiliary requests into the appeal proceedings

Subsequent to the finding that the main request was in conformity with Articles 123 and 84 EPC, the board dealt with the request of both parties to remit the case to the department of first instance for consideration of the ground for opposition pursuant to Article 100(a) EPC together with Article 56 EPC. The board exercised its discretion under Article 111(1) EPC in favour of the parties and ordered remittal. As a consequence, there was no further substantive or procedural request with respect to the main request that required a decision by the board. The appellant's auxiliary requests filed during the appeal proceedings were no longer of relevance for the board's decision, since the appeal could be allowed and the decision under appeal be set aside on the basis of the higher- ranking main request. A decision of this board on the admission of the auxiliary requests was not required and would even have prejudiced the discussion of inventive step by the opposition division and would have run counter the rationale for the remittal. Moreover, a discussion of the admission of the auxiliary requests would have required the parties to engage in a prima facie assessment of the state of the art relevant for the issue of inventive step in order to ascertain the relevance of the requests. Therefore, the board rejected the request of the respondents to decide on the admission of the auxiliary requests.

7. In view of the remittal of the case to the department of first instance for consideration of the ground for opposition pursuant to Article 100(a) EPC together with Article 56 EPC, the board also had no power to review the decision of the department of first instance not to admit certain documents as late-filed (see point 3 of the board's communication dated 10 January 2014), as these documents are relevant only when assessing inventive step.