T 0361/08 (RNA polymerase/ISTITUTO RICERCHE BIOLOGIA) 03-12-2009

1. The appeal is admissible.

Admission of the main request (claims as granted) into appeal proceedings

2. According to Article 13(1) RPBA, any amendment to a party's case after it has filed its grounds of appeal may be admitted and considered at the board's discretion. The 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.

3. The board notes that it was only after the board's communication under Article 15(1) RPBA and shortly before the oral proceedings, that the appellant reverted to the granted claims as its main request (cf. Sections IX and X supra). Hence the present main request was filed after the filing of the statement of grounds of appeal. Thus it is an amendment to the appellant's case within the meaning of Article 13(1) RPBA. Accordingly, it lies within the board's discretion to admit this request into the appeal proceedings.

4. When exercising its discretion under Article 13(1) RPBA, the board cannot ignore what happened during the oral proceedings before the opposition division.

5. The board considers that the minutes correctly reflect the course of the oral proceedings before the opposition division since there is no reason for the board to doubt the completeness or correctness of the minutes. Firstly, no request for correction of the minutes has been filed by any of the parties. In fact, the appellant explicitly submitted in the oral proceedings before the board that the minutes were correct as to what happened during the oral proceedings before the first instance but only the legal conclusions and the consequences that the opposition division drew therefrom were wrong. Secondly, there is no indication in the first instance decision given orally and subsequently put in writing that the minutes could be wrong or incomplete.

6. According to the minutes, after a discussion on the main request which was then on file, namely on the claims as granted, and a short break of the oral proceedings it was announced that the main request did not fulfil the requirement of Article 123(2) EPC (cf. page 1 to page 2, first paragraph of the minutes) and the patentee was also informed that this objection applied - at least partly - to all the auxiliary requests then on file (cf. page 2, second paragraph of the minutes). In reaction to this objection under Article 123(2) EPC, the patentee submitted an amended main request and "indicated that he wishes to withdraw all other requests on file" (cf. page 2, third paragraph of the minutes). The discussion continued on the basis of the amended main request. In response to a further objection under Article 123(2) EPC, the patentee deleted claim 11 of the amended main request and confirmed that this was its "sole request"(cf. page 3, fourth paragraph of the minutes). After the discussion on this sole request and the announcement of the chairman that the opposition division "found claims 1 and 6 to lack inventive step" the patentee was asked whether it would file further requests. After a short break the patentee stated that it "did not wish to file further requests but intended to appeal" (cf. page 6, third and fourth paragraphs of the minutes). According to the last page of the minutes (EPO Form 2309.2) a decision revoking the patent was announced at the end of the oral proceedings and the oral proceedings were closed.

7. The appellant argues that, during oral proceedings, the opposition division announced an "oral" decision on the main request being the claims as granted which terminated the debate with respect to this request and that, once the decision was announced, it was no longer possible for the patentee to withdraw this request from the opposition proceedings.

8. It is true that the opposition division was not precluded from giving a substantive interlocutory decision within the meaning of Article 106(3) EPC 1973 in the course of opposition proceedings (see for example T 390/86, OJ EPO 1989, 30 and T 537/05 of 29 March 2007). Indeed, had the opposition division taken a decision on the main request being the claims as granted, the appellant would have been barred from withdrawing them later (cf. T 54/00 of 19 December 2000, Reasons, point 4; also T 537/05, supra, Reasons, point 1.6).

However, the board does not concur with the appellant's argument that the chairman announced such a decision during the oral proceedings before the opposition division for the reasons that follow.

It is clear from the minutes and the EPO Forms 2309.2 and 2339 that at the end of the oral proceedings a decision revoking the patent was announced. This was in accordance with Rule 68(1), first sentence EPC 1973 which was then in force and stipulates that where oral proceedings are held before the EPO, the decision may be given orally. The minutes also clearly indicate that this decision was based on the sole remaining request which did not encompass claims 2,3,9 and 10 as granted.

The board also notes that the minutes contain, with regard to the main request being the claims as granted and which was discussed at the beginning of the oral proceedings, the following statement:

"The proceedings were reopened at 10.50 and it was announced that the MR (main request, added by the board) did not fulfill the requirement of Article 123(2) EPC (cf. page 1 to page 2, first paragraph of the minutes).

However, the board considers that it can not reasonably be understood from this statement and the circumstances of the present case that the opposition division had taken an oral decision on the main request which was then on file. In contrast to case T 537/05 (supra), the wording of this statement does not comprise words such as "decide" or "decision" which could possibly - but not necessarily (see T 473/98, OJ EPO 2001, 231, Reasons, point 2.4) - imply that a decision had actually been taken. The wording of this statement rather indicates that the opposition division gave a mere opinion on the non-compliance of the claims as granted with the requirements of Article 123(2) EPC. Moreover, after the announcement in question the opposition division informed the patentee that the objection under Article 123(2) EPC also applied to the auxiliary requests then on file and, subsequently, it gave the patentee the opportunity to submit a new request (cf. page 2, second paragraph of the minutes). The board regards this as a further indication that the opposition division announced a mere opinion which was not intended to terminate the proceedings on this issue but to continue the discussion on it. In fact, the patentee withdrew all his requests then on file and filed an amended main request as his sole request (cf. page 2, third paragraph of the minutes).

9. In addition, the board deems it appropriate to take into account the statement of grounds of appeal which was filed by the appellant's professional representative who had attended the oral proceedings before the first instance. Had the appellant understood the announcement in question as a substantive oral decision within the meaning of Rule 68(1), first sentence EPC 1973 it could have legitimately expected reasons for that decision in writing (Rule 68(2), first sentence EPC 1973). However, although the reasons of the decision under appeal were based exclusively on the patentee's single request maintained at the end of the oral proceedings, no submission was made in the statement of grounds of appeal that the decision under appeal was not fully reasoned, let alone an incorrect legal conclusion or procedural violation alleged. Moreover there is no submission with regard to Article 123(2) EPC under which the opposition division objected to the claims as granted and to the claims according to the auxiliary requests. The appellant merely disputed the finding of the opposition division on inventive step. However, according to the minutes, inventive step was only discussed with regard to the subject-matter of the claims according to the sole request on which the decision under appeal is based.

In view of these facts, the board is of the opinion that the appellant and his professional representative had understood that the opposition division announced an opinion on the main request being the granted claims which did not amount to an oral substantive decision and that this request was not part of the decision since it was subsequently withdrawn by the patentee during the oral proceedings before the first instance. The board further notes that it was not until its reply to the board's communication under Article 15(1) RPBA that the appellant submitted that the opposition division took a decision on the request being the claims as granted and that therefore this request remained in the opposition proceedings with the consequence that the opposition division should have provided a written decision on the subject-matter of this request.

10. In view of the above, the board comes to the conclusion that the announcement in question was a mere opinion of the opposition division relating to a request which was subsequently withdrawn and not a decision within the meaning of Rule 68(1), first sentence EPC 1973.

11. Turning now to the appellant's argument that the main request being the granted claims could also not have been withdrawn in oral proceedings before the first instance since the opposition division had closed the debate on this request by announcing the statement in question.

The board is not persuaded by the appellant's argument for the reasons that follow.

Where oral proceedings are held, the decision may be given orally and becomes effective by virtue of its being pronounced (cf. decision of the Enlarged Board of Appeal G 12/91, OJ EPO 1994, 285, Reasons, point 2). The point in time at which a decision given orally enters into force, i.e. the moment it is pronounced, is not the last moment at which parties may still submit observations (cf. G 12/91, supra, Reasons, point 3). In oral proceedings submissions can be made until the closing of the debate which is fixed by the decision-making department - having first heard the parties' submissions - to allow itself time to consider its decision (cf. G 12/91, supra, Reasons, point 3; J 42/89 of 30 October 1991; T 762/90 of 29 November 1991; T 595/90, OJ EPO 1994, 695, Reasons, point 1). Once the debate has been closed in oral proceedings no submissions may be made by the parties unless the decision-making department decides to re-open this debate.

In the board's view, the opposition division did not close the debate on all issues with the announcement of its opinion. However, even if the board accepted the appellant's argument that the opposition division, by announcing its opinion on all the requests then on file, had closed the debate on the main request being the claims as granted, the opposition division re-opened this debate immediately after the announcement by giving the patentee explicitly the opportunity to submit a new request (cf. page 2, second paragraph of the minutes). Hence the board comes to the conclusion that the debate was not closed at the time when the patentee withdrew its main request being the claims as granted in the first instance proceedings.

12. On the basis of the foregoing the board concludes that the appellant was not barred from withdrawing its main request being the claims as granted in oral proceedings before the opposition division. Since no decision was announced on this main request and the appellant validly withdrew this request during the oral proceedings before the opposition division, this request was no longer existing in first instance proceedings. Consequently, the opposition division acted correctly in giving no decision on this request at the end of the oral proceedings and no reasons in writing. The same applies to the further requests which, accordingly to the reasons set out above, the appellant validly withdrew during the oral proceedings before the opposition division.

13. In view of the particular circumstances of the first instance proceedings, the board considers it appropriate, when exercising its discretion under Article 13(1) RPBA, to take into account also the provisions of Article 12(4) RPBA.

According to Article 12(4) RPBA, the board has the discretionary power to hold inadmissible requests which could have been presented or were not admitted in the first instance proceedings. In the board's view this applies all the more to requests that were filed and subsequently withdrawn in the first instance proceedings, since such a course of events clearly shows that these requests could have been presented in the first instance proceedings.

In the present case, the appellant validly withdrew his request being the claims as granted in the oral proceedings before the opposition division (cf. points 4 to 12 above). If the appellant had filed such a request with its statement of grounds of appeal, the board would have exercised its discretion according to Article 12(4) RPBA and would have most likely not admitted this request into the appeal proceedings as can be seen from the board's communication pursuant to Rule 100(2) EPC. In this communication, the board clearly indicated that in its preliminary opinion the main request then on file, which had been filed with the statement of grounds of appeal, would not be admitted into the appeal proceedings in accordance with Article 12(4) RBPA since it was submitted on 21 September 2007 as a third auxiliary request and subsequently withdrawn in the first instance proceedings (cf. Sections V and VII supra).

In the board's view, the above criteria, which are applied by the board when exercising its discretion under Article 12(4) RPBA, can also be applied by the board when exercising its discretion under Article 13(1) RPBA. The fact that the appellant had chosen to file the present main request after it filed its grounds of appeal should not put the appellant in a better position than if it had filed this request with the statement of grounds for appeal. Otherwise it would be easily possible for the appellant to circumvent the provisions of Article 12(4) RPBA.

Consequently, the fact alone that the present main request was submitted and subsequently withdrawn in the first instance proceedings is for the board a sufficient reason not to admit this request into appeal proceedings, exercising its discretion in accordance with Article 13(1) RPBA. In addition the present main request was submitted at a very late stage of the appeal proceedings and new substantive issues could well arise due to the presence of granted claims for which a decision of the first instance was not given because of the patentee's withdrawal. Therefore the board takes the view that the patentee's behaviour counteracts procedural economy.

14. The appellant further argues that it is always the patentee's right to revert to the granted claims in opposition appeal proceedings against the revocation of a patent.

It is established jurisprudence that the function of appeal proceedings is to give a judicial decision upon the correctness of a separate earlier decision taken by a department of the European Patent Office (cf. "Case Law of the Boards of Appeal of the EPO", 5th edition 2006, VII.D.1). However, it is not the purpose of appeal proceedings to give the patent proprietor the opportunity to recast its claims as it sees fit and to have all its requests admitted into the appeal proceedings. This principle is mirrored in Articles 12(4) and 13 RPBA.

It follows from the above that it is certainly not the appellant patentee's right to revert to the granted claims in appeal proceedings if these claims did not form a basis for the decision under appeal because the request comprising these claims was withdrawn in the first instance proceedings. Rather it lies within the board's discretion to admit such a request.

15. For the above reasons the board, exercising its discretion under Article 13(1) RPBA, decided not to admit the appellant's main request being the claims as granted into the appeal proceedings.

Admission of auxiliary requests I, II, III and V filed on 3 November 2009 into the appeal proceedings

16. Auxiliary requests I, II, III and V were filed after the board's communication under Article 15(1) RPBA and shortly before the oral proceedings. Since these requests were filed after the filing of the statement of grounds of appeal, they are an amendment to the appellant's case within the meaning of Article 13(1) RPBA. It lies consequently within the board's discretion to admit these requests into the appeal proceedings.

17. When exercising its discretion under Article 13(1) RPBA regarding the admission of said auxiliary requests, it is again appropriate in the present case to take into account what happened during the oral proceedings before the first instance.

It is clear from the minutes that, after the patentee had validly withdrawn all requests then on file which comprised inter alia claims 2-3 and 9-10 as granted, it maintained only its sole request at the end of the oral proceedings (cf. Section III above). This sole request, on which the appealed decision is based, does not comprise granted claims 2-3 and 9-10.

18. In view of the course of the oral proceedings before the opposition division, the criteria which are applied by the board, when exercising its discretion under Article 12(4) RPBA, can also be applied by the board, when exercising its discretion under Article 13(1) RPBA in the present case (cf. also point 13 above).

It is evident that a request which comprises inter alia claims 2-3 and 9-10 as granted could have been filed in first instance proceedings, since all requests comprising these claims were filed and subsequently withdrawn during the oral proceedings before the opposition division. Hence, in its communication under Rule 100(2) EPC, the board clearly indicated that in its preliminary opinion the appellant's main request, which comprised said granted claims and was filed with the statement of grounds of appeal, was considered not to be admissible into the appeal proceedings in accordance with Article 12(4) RPBA.

The board considers that the same would have applied if the present auxiliary requests I, II, III and V had been filed with the appellant's statement of grounds of appeal. It is true that claim 1 of auxiliary request I is a combination of granted claims 1 and 3, claim 1 of auxiliary request II a combination of granted claims 1 and 2, claim 1 of auxiliary request III a combination of granted claims 1, 2 and 3 and claim 1 of auxiliary request V a combination of amended claim 1 with granted claim 3 (cf. Section X supra). However, by combining the granted or amended claim 1 with granted dependent claims 2 and/or 3 does not alter the board's view as far as its power under Article 12(4) RPBA is concerned. In first instance proceedings the patentee filed and subsequently withdrew requests which comprised dependent claim 2 and 3 which means that the subject-matter of the before-mentioned combinations was already at issue before the opposition division. Therefore, the board takes the view that requests comprising such combinations of claims could have been filed in first instance proceedings. However, by not filing requests comprising the subject-matter of granted claims 2 and/or 3 in first instance proceedings, the patentee avoided deliberately an opposition division's decision on the subject-matter of these granted claims as it did by withdrawing all requests comprising granted claims 2-3 in the oral proceedings before the opposition division.

For the board this is a sufficient reason not to admit auxiliary requests I, II, III and V into appeal proceedings, exercising its discretion in accordance with Article 13(1) RPBA. Apart from that these auxiliary requests of claims were filed at a very late stage of the appeal proceedings and new substantive issues could well arise because of the new combinations of claims. Therefore, the board considers the patentee's behaviour counteracting procedural economy.

19. For the above reasons the board, exercising its discretion under Article 13(1) RPBA, decided not to admit the appellant's auxiliary requests I, II, III and V into the appeal proceedings.

Auxiliary request IV filed during the oral proceedings on 3 December 2009

20. The subject-matter of the claims of auxiliary request IV corresponds essentially to that of claims 1 and 3 to 5 of auxiliary request VI which was filed with the statement of grounds of appeal (cf. Section V supra) and is identical to the sole request considered by the opposition division in its decision. The claims according to auxiliary request IV were amended in such a way as to overcome the objections raised by the board under inter alia Article 84 EPC 1973 in the communication pursuant to Rule 100(2) EPC and during the oral proceedings. These amendments and the request itself are regarded as a direct reply to the board's objections, i.e. a justifiable reaction to the board's comments made in the first communication and during the oral appeal proceedings. Moreover, the subject-matter of auxiliary request IV does not raise substantive issues other than those already raised with regard to auxiliary request VI. Therefore, the board, exercising its discretion under Article 13(1) RPBA, decided to admit auxiliary request IV into the appeal proceedings.

Articles 123(2),(3) EPC

21. The application as filed states, with reference to a method for producing in vitro HCV RdRp activity, that "... the proteins containing sequences of NS5B can be expressed in either eukaryotic or prokaryotic heterologous systems: the recombinant proteins containing sequences of NS5B, either purified to apparent homogeneity or present in extracts of overproducing organisms, can catalyse the addition of ribonucleotides ... either in a template-dependent (RdRp) or template-independent (TNase) fashion" (cf. page 4, lines 1 to 10). The production of recombinant HCV NS5B protein in insect host cells Spodoptera frugiperda (Sf9) and in E. coli is shown, respectively, in Examples 1 and 8 of the application as filed. Example 6 discloses the purification of the recombinant HCV NS5B protein from Sf9 host cells using several chromatographic steps. Silver- and immuno-staining of SDS-PAGE are used to identify the chromatographic fractions containing the HCV NS5B protein and to assess their degree of purity. The resulting purified (to apparent homogeneity) HCV NS5B protein is tested for HCV RdRp activity.

22. The application as filed discloses the baculovirus vectors pBac5B and pBac25, the former containing a cDNA region encoding the HCV NS5B protein (SEQ ID NO: 1) and the latter a cDNA region coding the HCV-BK polyprotein (SEQ ID NO:2) (cf. page 6, lines 19 to 30). These vectors are used to produce the recombinant baculovirus clones Bac5B and Bac25 (cf. paragraph bridging pages 6 and 7). Infection of Sf9 host cells with Bac25 results in the detection of correctly-processed HCV NS2, NS3, NS4B, NS4A, NS5A and NS5B proteins (cf. paragraph bridging pages 7 and 8). Claims 2 and 3 of the application as filed contemplate the use of a (recombinant) NS2-NS5B precursor for "... generating, by means of multiple proteolytic events that occur in the overproducing organism, an enzymatically active form of NS5B", which, in this way, is incorporated in a reaction mixture (enzymatic test) for producing in vitro HCV RdRp activity (claims 6 and 7 as filed).

23. In view of the above cited general disclosure and the exemplified subject-matter, the board is convinced that the application as filed contemplates the use of a recombinant HCV NS5B protein purified to apparent homogeneity in a method for producing in vitro HCV RdRp activity. The features introduced into claim 1 ("recombinant HCV NS5B purified to apparent homogeneity"), and the claims dependent thereon, are not a novel selection of subject-matter. They were originally contemplated in the application as filed. Moreover, they are an admissible limitation of the claims as granted. Thus, the requirements of Articles 123(2),(3) EPC are considered to be fulfilled.

Article 84 EPC 1973

24. The term "recombinant" qualifies the HCV NS5B protein used in the method of claim 1 as having been produced recombinantly. This is a language commonly used in patent applications/patents. In the absence of any specific characteristics associated to the recombinant HCV NS5B protein, the said qualification introduces no particular limitation and must be broadly interpreted. However, this alone is not a sufficient reason to object any lack of clarity (cf. "Case Law", supra, II.B.1.1.4, page 191).

25. The degree of purity of the recombinant HCV NS5B protein is assessed in the patent-in-suit "by silver- and immuno-staining of SDS-PAGE" (cf. inter alia page 8, lines 19-20, 23-24 and 27). In line therewith, the feature "apparent homogeneity" refers to the presence of homogeneous recombinant HCV NS5B protein determined within the detection limits of these methods or of similar ones (cf. point 3.4.2, page 5, lines 14 to 17 of the decision under appeal). Contrary to the appellant's view (cf. Section XIII supra), that feature requires the recombinant HCV NS5B protein to be free from all other proteins and not from HCV proteins only. In this context, it is worth noticing that Example 5 of the patent-in-suit describes a unique behaviour of the HCV NS5B protein which is used to separate that protein from the bulk of cytoplasmic proteins of Sf9 host cells or, in Example 8, from lysates of E. coli (cf. paragraphs [0036] and [0043] of the patent-in-suit).

26. The requirements of Article 84 EPC 1973 are thus fulfilled.

Article 54(1) EPC 1973

27. Document D3 refers to the preparation of tissue homogenates and subfractions thereof from fresh native HCV-infected human liver tissue and their use in a RNA polymerase assay with a synthetic RNA primer-template. The activity detected "is dependent on the presence of all four ribonucleoside triphosphates, as well as both template and primer RNA strands, indicating that the incorporation reflects the elongation activity of an RNA-dependent RNA polymerase". Document D3 states:"we have partially purified the enzymatic activity using a variety of chromatographic separations" (in bold by the board).

28. The board considers that, for the purpose of establishing novelty, in the context of method claim 1 a partially purified enzymatic activity cannot anticipate an enzymatic activity of a purified enzyme ("at apparent homogeneity") which is an explicit requirement for the HCV NS5B protein which is to be used (cf. inter alia T 90/03 of 17 March 2005, Reasons, points 11 to 13). Since this feature alone confers novelty to the claimed method, it is not necessary to further discuss, inter alia, whether the HCV RdRp activity detected in document D3 can be directly equated to the HCV NS5B protein or whether the feature "recombinant" in claim 1 can differentiate the HCV NS5B protein used in that claim from a non-recombinant HCV NS5B protein such as that used in document D3.

29. The board cannot follow the respondent's argument that the presence in document D3 of a primer-dependent RdRp activity indicates, at least implicitly, that the degree of purification achieved for that RdRp activity is similar to that achieved in the patent-in-suit for the recombinant HCV NS5B protein (cf. Section XIV supra). Although in the patent-in-suit the RdRp activity of cellular extracts of Bac25- and Bac5B-infected Sf9 cells is reported to be primer-independent and a primer-dependent RdRp activity is detected only with a purified HCV NS5B protein (and a homopolymeric RNA template) (cf. paragraphs [0029], [0040] and [0041] of the patent-in-suit), there is no detailed information on the specific primer requirements (dependent or independent) of the RdRp activity for partially purified HCV NS5B proteins such as, for instance, those of the several HCV NS5B containing fractions obtained in the purification method of Example 6 (cf. paragraphs [0037] to [0039] of the patent-in-suit). Moreover, the primer-dependency of the RdRp activity appears also to be related, at least to a certain extent, to the properties of the template used (ability or inability to form hairpins) (cf. paragraph [0041] of the patent-in-suit), for which document D3 is completely silent. Thus, no conclusions can be drawn on the purity of the RdRp activity of document D3 on the sole basis of its primer-dependency.

30. It follows from the above, that document D3 does not anticipate the claimed subject-matter. Therefore, the requirements of Article 54(1) EPC 1973 are fulfilled.

Article 56 EPC 1973

31. The disclosure of document D3, which represents the closest prior art, has already been discussed in relation to novelty (cf. point 27 supra). The document refers to the "development of an assay for HCV RdRp and the isolation of complexes containing replicase activity" as a useful step "in the identification of compounds that can interrupt the viral (HCV) replicative cycle". It thereby provides an explicit motivation for the skilled person to develop an in vitro assay for HCV RdRp activity.

32. Starting from this prior art, the technical problem to be solved is the provision of an assay for HCV RdRp activity. The claimed method, which uses a recombinant HCV NS5B protein purified to apparent homogeneity, solves that technical problem (cf. paragraphs [0009] to [0012] of the patent-in-suit).

33. The appellant does not dispute that, although there is no explicit reference in document D3 to the HCV NS5B protein, there is nevertheless a large body of prior art which identifies the HCV RdRp activity with the HCV NS5B protein, in particular, with recombinant HCV NS5B protein (cf. inter alia documents D8 and D11). Thus, it would be have been obvious for the skilled person to consider the HCV NS5B protein as being responsible for the RdRp activity described in document D3. However, the appellant held that, although it might be derivable from that prior art that the HCV NS5B protein is necessary for obtaining the HCV RdRp activity, it cannot be derived therefrom that this protein is also sufficient for that activity. In this respect, the appellant points to the reference in document D3 to "complexes containing replicase activity" which in its view motivates the skilled person to look for complexes containing the HCV NS5B protein rather than for just the HCV NS5B protein. The more so in consideration of document D5 where the molecular weight of a native HCV NS5B-related antigen detected in human liver is reported to be larger than that of a recombinant HCV NS5B protein (cf. paragraph bridging pages 269 and 270 of document D5) (cf. Section XIII supra).

34. The board is not convinced by the above arguments as it does not see the reference to "complexes containing replicase activity" in D3 as a reason for the skilled person to turn his/her attention away from developing an HCV RdRp assay based on the HCV NS5B protein alone as the document is considered to suggest. This is because: firstly, in view of the preceding paragraph in D3 that indicates that the RdRp activity is dependent on the presence of all four ribonucleoside triphosphates, divalent cations as well as both template and primer RNA strands, the skilled reader would have possibly understood the term "complex" as simply referring to such interactions; and, secondly, there is no suggestion in document D3, let alone an indication, of the possible nature or (structural) characteristics of such complexes nor a reference to a possible contribution of other unspecified (cellular, viral) factors to the RdRp activity which would have required extensive investigation.

35. Moreover, the board does not see the reference in document D5 to a "slightly larger" molecular weight of a native HCV NS5B-related antigen from human liver in comparison to that of a recombinant HCV NS5B protein (cf. point 33 supra) as again suggesting a possible association of a native HCV NS5B protein with other (cellular, viral) proteins or factors and as information turning the skilled person's attention away from the straightforward development of the HCV RdRp assay suggested by D3. Document D5 explicitly states that the "discrepancy may have resulted in different host cells, which were cultured mammalian cells in Grakoui's (recombinant) study ... and were human liver cells in this study" (cf. page 270, left-hand column, lines 2 to 5), meaning that the (slight) difference in the molecular weight may have arisen from the particular expression system used to produce the recombinant HCV NS5B protein. The board fails to see in this disclosure any suggestion that may have led the skilled person to believe that the HCV RdRp activity could not be achieved with purified HCV NS5B protein alone and that other unknown (cellular, viral) factors would have been required to achieve that activity.

36. In the board's judgement, for the skilled person it would have been obvious to take the available recombinant HCV NS5B protein (purified to homogeneity), such as that of inter alia document D8, and to use it in the RdRp assay suggested in document D3. No obstacles are seen in the prior art to the development of such an assay based on those teachings.

37. In fact, related prior art had already shown that purified poliovirus RNA-dependent RNA polymerase is sufficient for an RdRp assay, indeed using both a native and a recombinant RdRp enzyme alone, wherein the latter was obtained from several expression systems, namely bacterial (E. coli), insect (Sf9) and mammalian (HeLa) host cells (cf. document D28). Although the presence of different contaminating (cellular) activities might influence some properties of partially purified enzymes, such as primer-dependency and dimer-length of the resulting RNA products (as also reported in the patent-in-suit), all purified RdRp enzymes have the same specific activity and no other (cellular, viral) factors are required to achieve their enzymatic activity.

38. In this respect, the appellant argued (cf. Section XIII supra) that poliovirus is a picornavirus and not a member of the Flaviviridae family, such as the flaviviruses and the pestiviruses, to which HCV is distantly related (cf. inter alia page 1112, right-hand column, last paragraph in document D7). Nevertheless, poliovirus is also a single-stranded RNA virus of positive polarity and its viral RNA polymerase is released from the COOH terminus of a large polyprotein precursor by protease-catalyzed autocatalytic cleavage, as is the case for HCV RdRp. Indeed, some similarities between both RNA viruses, poliovirus and HVC, were already known in the art (cf. inter alia page 297, right-hand column, lines 10 to 6 from the bottom in document D14), in particular, the presence of the conserved specific sequence Gly-Asp-Asp (GDD) recognized in all RdRp (cf. page 300, right-hand column, lines 6 to 14 in document D14 and paragraph bridging pages 1107 and 1110 in document D7). In fact, whereas no significant homology is found between the structural and non-structural proteins of HCV and those of the distantly related flavivirus (JEV) and pestiviruses (BVDV), a detectable homology is nevertheless found in NS3 (encoding a serine protease responsible for the trans-cleavage) and in NS5 (cf. paragraph bridging pages 1112 and 1113 and Table 2 of document D7).

39. In this context, it is worth pointing out that the presence in the NS5B region of the HCV genome of a sequence encoding the conserved Gly-Asp-Asp (GDD) motif is accepted in all the cited prior art as a direct and clear indication that the HSV NS5B region encodes a putative HCV NS5B protein with the HCV RdRp activity. Even though, as rightly argued by the appellant (cf. point XIII supra), this prior art is mostly concerned with the structure, organization and processing of a recombinant HCV genome and it does not actually provide any experimental evidence to support that assumption, i.e. showing the HCV RdRp activity of a HCV NS5B protein, the board fails to see any piece of prior art or evidence speaking against the correctness of that assumption and as casting serious doubts and uncertainty on the use of a recombinant HCV NS5B protein in the RdRp assay suggested in document D3. The availability of recombinant HCV NS5B proteins has not been disputed and is supported by the disclosures in the prior art of suitable expression constructs producing recombinant HCV NS5B proteins (cf. inter alia page 8148, left-hand column, last full paragraph, and Figure 1, page 8153, left-hand column, last paragraph to page 8154, left-hand column, first paragraph, and page 8155, left-hand column, last paragraph in document D8 and page 1386, last line in Table 1 of document D11).

40. In conclusion, no inventive contribution is seen in the claimed method and, therefore, the requirements of Article 56 EPC 1973 are not considered to be fulfilled. Thus auxiliary request IV is not allowable.

Auxiliary request VI filed with the statement of grounds of appeal

41. Auxiliary request VI is identical with the auxiliary request filed with the statement of grounds of appeal and thus with the sole request forming the basis for the decision under appeal (Section X supra). In view of this, the board, exercising its discretion under Article 12(4) RPBA, decided to admit this request into the appeal proceedings.

Article 56 EPC 1973

42. The board considers that the above reasoning outlined in respect of the auxiliary request IV applies mutatis mutandis to the subject-matter of auxiliary request VI, since in this request the HCV NS5B protein is defined in terms of the feature "wherein said NS5B is expressed in either an eukaryotic or prokaryotic heterologous system" (cf. Sections IV and V supra) which can be equated to the feature "recombinant" of auxiliary request IV.

43. Thus, for the reasons given above, the subject-matter of auxiliary request VI is considered not to fulfil the requirements of Article 56 EPC 1973. Hence, auxiliary request VI is also not allowable.

Auxiliary requests VII and VIII for remittal of the case to the first instance

44. According Article 111(1), second sentence EPC 1973, the board may either exercise any power within the competence of the department which was responsible for the decision appealed or remit the case to that department for further prosecution.

45. The appellant requested remittal to the opposition division should its main request, auxiliary requests I, II, III and V not be admitted into the appeal proceedings (auxiliary request VII)(cf. Section XV supra).

46. Indeed the board decided not to admit the main request and the auxiliary requests I, II, III and V into the appeal proceedings for the reasons as set out above (cf. points 1 to 19). However, it would contravene the function of appeal proceedings (cf. point 14 above) and the provisions of Articles 12(4) and 13(1) RPBA if the present case were remitted to the first instance for further prosecution simply because the board had not admitted the above-mentioned requests into the appeal proceedings. Thus, the appellant's auxiliary request VII is not allowable.

47. The appellant further requested to remit the case to the opposition division for further prosecution on the basis of auxiliary request IV (auxiliary request VIII) (Section XV supra).

48. However, the board admitted auxiliary request IV into the appeal proceedings (cf. point 20 supra) and decided within the opposition division's competence that auxiliary request IV is not allowable because the claimed subject-matter does not involve an inventive step (cf. points 31 to 40 supra). If the board remitted the present case to the first instance, the opposition division would be bound by the ratio decidendi of the board pursuant to Article 111(2), first sentence EPC 1973. It follows that the board's finding that the subject-matter of claim 1 of auxiliary request IV does not involve an inventive step would be binding on the opposition division in case of a remittal. Hence, the board has no reason for remitting the case to the opposition division for further prosecution on the basis of auxiliary request IV.