T 0689/19 - (III) Intervention and res judicata

Key points

•  This is the second appeal in this opposition case. In T 0950/13, the Board remitted the case. 
• "When justifying the remittal to the opposition division, the board drew attention to the fact that the decision then under appeal dealt solely with the grounds of added matter and lack of sufficiency of disclosure, but had not decided on other grounds for opposition such as inventive step (point 6). It remitted the case to the department of first instance for further prosecution (order)." 
• Multiple parties intervene in the proceedings under Article 105 EPC.
• " All the interventions were filed after decision T 950/13 had been issued following an appeal by the patent proprietor against the decision of the opposition division dated 1 February 2013 revoking European patent no. 1 610 780. Decision T 950/13 remitted the present case to the opposition division for further prosecution of outstanding issues raised by the opposition filed on 21 January 2011. " 
•  " In their notices of intervention and on appeal, the appellants [itnerveners] argued that the medical use claimed in the main request was not sufficiently disclosed. They asked that this ground be reconsidered, and argued that the application did not disclose a plausible concept of treatment but a mere allegation without proof that dasatinib treats the same cancers as imatinib. " 
• The Board does not admit these objections.
•  The Board: " According to the established case law of the boards of appeal, res judicata is a generally accepted principle which means that a matter which has been judicially determined in a final manner between parties by a tribunal of competent jurisdiction cannot become the subject of subsequent proceedings between the same parties or their successors" 
• "Hence a board's decision is an absolute bar to subsequent proceedings on the same matter between the same parties (or their successors). The order and the reasons for the decision determine the extent to which the decision is final (T 460/95, OJ EPO 1998, 587, point 2 of the Reasons). The "same matter" refers to all issues of fact and law which have been finally settled (T 694/01, OJ EPO 2003, 250, point 2.10 of the Reasons; T 167/93, OJ EPO 1997, 229, point 2.5 of the Reasons; see also T 843/91, OJ EPO 1994, 832, headnote and point 3.4.2 of the Reasons; T 153/93, point 2 of the Reasons; T 308/14, catchword and point 1.3)."
• In T694/01, the Board had remitted with an order specifying the claims.  T167/93 r.2.5 states "any generally recognized principle of estoppel by rem judicatam for the Contracting States is of extremely narrow scope". For the decisions cited as "see also", T 843/91 deals with a remittal specifying the claims in the order. T 153/93, however, indeed says that "The previous finding of the Board of Appeal that Claims 1 to 5 as amended in the course of oral proceedings were novel, were clear and were inventive, are therefore res judicata. Furthermore, the findings of fact i.e. the clarity of the term "normal background lawn" as well as the construction of the disclosure of DE-A-2 924 861 in its entirety, are findings of fact that were part of that decision and are likewise binding upon the parties in all subsequent proceedings before the EPO, including its judicial arm, the Boards of Appeal" but again the previous decision T761/90 had an order specifying the allowable claims.
• In T 308/14, the earlier appeal decision was indeed to remit for further prosecution, i.e. not with an order to maintain the patent with certain claims. However, in that decision, it was held that: 'This decision constituted res judicata and thus was binding on the opposition division in the subsequently resumed opposition proceedings (Article 111(2) EPC)." So in that decision, the binding effect under Article 111(2) EPC and res judicata were seen as one and the same.
• However, as held in T 0449/15, "The principle of res iudicata and that of the binding effect of the ratio decidendi pursuant to Article 111(2) EPC 1973 are not mutually exclusive, but complement one another. " 
• The Board then takes a deep dive and gives an interesting analysis of the concepts of res judicata and binding effect. Extensive internal citations are omitted in the following.
• " The principle of res judicata and that of the binding effect pursuant to Article 111(2) EPC are not identical, but complementary. The binding effect of the ratio decidendi pursuant to Article 111(2) EPC is limited to proceedings regarding the same application or patent following a remittal of the case after a (first) decision of a board of appeal. The department dealing with the case in the subsequently resumed proceedings and the board dealing with a possible second appeal arising from these proceedings are bound by the ratio decidendi of the first decision. This binding effect extends to matter which is not finally settled (res judicata), but encompassed by the ratio decidendi "  
• " On the other hand, it only applies "in so far as the facts are the same" []  The principle of res judicata is not limited to a situation of remittal for further prosecution but also applies in such a situation. Matter which has become res judicata is not open for reconsideration following remittal. Since this principle applies to all issues of fact which have been finally settled, it precludes a change of facts as contemplated by Article 111(2) EPC [] New facts, evidence or arguments seeking to cast doubt upon settled issues of fact cannot be considered. "
• " The nature of opposition and opposition appeal proceedings therefore does not support the view that a matter finally settled by an appeal decision remitting the case to the opposition division for further prosecution only binds the parties to the appeal proceedings and does not prejudice an intervener that only becomes a party to the opposition proceedings subsequent to the remittal of the case. The result of applying the principle of res judicata depending on the party status in the appeal proceedings leading to remittal would be absurd. The adjudged matter had to be accepted by the initial parties, and the opposition division had no power to re-open such matter in respect of those parties, whereas interveners would be allowed to disregard the final findings of the decision remitting the case to the opposition division and start opposition proceedings anew. However, in opposition proceedings it is not possible to take separate decisions for different parties on the form of the patent to be maintained."  
It is also not possible to conceptually separate the opposition proceedings into two different parts, the first one being the original opposition and the second one opposition proceedings including the interveners. A European patent can only be the subject of one common opposition procedure []. The filing of oppositions by different opponents or interveners does not lead to separate opposition proceedings for each party, not even conceptually.
• " In view of the above, the board considered whether the object and purpose of Article 105(1) EPC might justify and constitute an exception to both the principle of res judicata and the binding effect under Article 111(2) EPC." 
The board therefore agrees with decision T 694/01 that there "is nothing in the EPC to suggest that the intervention of an assumed infringer opens a new stage of proceedings which invalidates binding results of the proceedings to date" (T 694/01 []).
• In T 694/01, the Board had in the first appeal decided on the wording of the claims and remitted for maintenance of the patent in amended form with a description to be adapted, and the interveners intervened only at that stage.
• " In the case at hand, the grounds of opposition of added matter and sufficiency of disclosure have been finally determined in decision T 950/13. These grounds are therefore not open to an intervention and can be considered neither by the opposition division nor by the board on appeal. As set out above, due to the principle of res judicata, it is not possible to change the facts underlying the decision T 950/13 even if this change is acceptable in view of the ratio decidendi." 
  
  
• As a comment, the effect of this decision seems to be that each finding of fact and conclusion of law by the Board is res judicata, and hence binding after a remittal, even if a party could successfully invoke the exception expressly foreseen by the legislator in Article 111(2) EPC. In other words, does this line of case law on res iudicata make the exception of Article 111(2) EPC a dead letter?

EPO 

The link to the decision is provided after the jump, as well as (an extract of) the text of the decision.

https://www.epo.org/law-practice/case-law-appeals/recent/t190689eu1.html

4. Decision T 950/13 - binding effect (Article 111(2) EPC) and res judicata

4.1 All the interventions were filed after decision T 950/13 had been issued following an appeal by the patent proprietor against the decision of the opposition division dated 1 February 2013 revoking European patent no. 1 610 780. Decision T 950/13 remitted the present case to the opposition division for further prosecution of outstanding issues raised by the opposition filed on 21 January 2011. The board in case T 950/13 found that the subject-matter of claim 1 directed to the use of dasatinib in the manufacture of a medicament for the treatment of chronic myelogenous leukemia (CML) was sufficiently disclosed. Although the application did not contain experimental evidence for dasatinib's Bcr-Abl kinase-inhibitory activity, the board was satisfied that the application disclosed at least a plausible technical concept for the treatment of CML by dasatinib, taking into account the known causative link between the Bcr-Abl oncogene and CML, the inhibition of Bcr-Abl kinase as an effective way to treat the disease, and dasatinib's functional equivalence to imatinib as a Bcr-Abl kinase inhibitor. As a consequence, the board took into account the post-published evidence (L. J. Lombardo et al., Journal of Medicinal Chemistry, vol. 47, 2004, pages 6658 to 6661, designated document (2)), which was held to confirm the Bcr-Abl kinase-inhibitory activity of dasatinib (T 950/13, points 3.3 to 3.7 of the Reasons). Arguments provided by the opposition division and opponent were addressed in points 3.3 to 3.6, 3.9 and 3.10 of the Reasons. The board therefore held that the subject-matter of claims 1 and 4 of the main request was sufficiently disclosed. However, the board held that the subject-matter of claim 2 of the main request, which was directed to the use of dasatinib for the manufacture of a medicament for oral treatment of CML resistant to imatinib, was not sufficiently disclosed (points 3.13 and 3.14 of the Reasons). This finding also applied to claim 2 of then-auxiliary request 1, which was directed to the same therapeutic use as claim 2 of the main request. This claim had been deleted in auxiliary request 2a. Claim 1 of this request being identical to claim 1 of the main request, the board held that the ground of opposition according to Article 100(b) EPC did not prejudice maintenance of the patent on the basis of auxiliary request 2a (point 5 of the Reasons). The board also upheld the opposition division's finding that the claims of auxiliary request 2a, which (except for a minor correction) corresponded to the claims of auxiliary request 3 considered by the opposition division, complied with Articles 123(2) and (3) EPC.

4.2 In their notices of intervention and on appeal, the appellants argued that the medical use claimed in the main request was not sufficiently disclosed. They asked that this ground be reconsidered, and argued that the application did not disclose a plausible concept of treatment but a mere allegation without proof that dasatinib treats the same cancers as imatinib. Appellant-opponents 2 and 5 also raised objections of added matter (Article 123(2) EPC). The appellants thus raised grounds on which a decision had been taken in case T 950/13. Relying on decision G 1/94, they argued that they had the right to challenge the findings of decision T 950/13. Relying on Article 111(2) EPC and the principle of res judicata, the respondent denies such right of interveners and appellants.

4.3 According to the established case law of the boards of appeal, res judicata is a generally accepted principle which means that a matter which has been judicially determined in a final manner between parties by a tribunal of competent jurisdiction cannot become the subject of subsequent proceedings between the same parties or their successors (T 934/91, OJ EPO 1994, 184, point 3 of the Reasons; T 153/93, point 2 of the Reasons; T 167/93, OJ EPO 1997, 229, points 2.2 to 2.5 of the Reasons). Decisions of the boards of appeal are res judicata both in form and substance, because there is no means of redress as to substance against them (G 1/97, OJ EPO 2000, 322, point 2(a) of the Reasons; T 694/01, OJ EPO 2003, 250, point 2.10 of the Reasons). This also applies to interlocutory decisions remitting the case for further prosecution (T 694/01, point 2.10 of the Reasons). The fact that the res judicata effect may be challenged by way of a petition for review (Article 112a EPC) does not call into question the final character of a decision of a board of appeal in the absence of a decision pursuant to Article 112a(5), second sentence, EPC re-opening the proceedings before the board of appeal (R 1/08, point 2.1 of the Reasons; T 584/09 of 1 March 2013, points 14 and 15 of the Reasons). Hence a board's decision is an absolute bar to subsequent proceedings on the same matter between the same parties (or their successors). The order and the reasons for the decision determine the extent to which the decision is final (T 460/95, OJ EPO 1998, 587, point 2 of the Reasons). The "same matter" refers to all issues of fact and law which have been finally settled (T 694/01, OJ EPO 2003, 250, point 2.10 of the Reasons; T 167/93,OJ EPO 1997, 229, point 2.5 of the Reasons; see also T 843/91, OJ EPO 1994, 832, headnote and point 3.4.2 of the Reasons; T 153/93, point 2 of the Reasons; T 308/14, catchword and point 1.3).

4.4 The binding effect of a decision is governed by Article 111(2) EPC. Pursuant to this provision, a department whose decision was appealed against is bound by the ratio decidendi of the board of appeal's decision if the case is remitted to the department for further prosecution. The ratio decidendi is the ground or the reason for making it, in other words the point in a case which determines the outcome of the judgment (T 934/91, OJ EPO 1994, 184, point 2 of the Reasons). The same binding effect applies to the board in the case of a subsequent appeal against a further decision of the department of first instance following remittal (self-binding effect, T 79/89, OJ EPO 1992, 283, point 3 of the Reasons; T 21/89, point 3.1 of the Reasons).

4.5 The principle of res judicata and that of the binding effect pursuant to Article 111(2) EPC are not identical, but complementary. The binding effect of the ratio decidendi pursuant to Article 111(2) EPC is limited to proceedings regarding the same application or patent following a remittal of the case after a (first) decision of a board of appeal. The department dealing with the case in the subsequently resumed proceedings and the board dealing with a possible second appeal arising from these proceedings are bound by the ratio decidendi of the first decision. This binding effect extends to matter which is not finally settled (res judicata), but encompassed by the ratio decidendi (see as an example T 817/00, point 3.2 of the Reasons: an objection of lack of novelty rejected by the first decision was reintroduced, after remittal, as an objection of lack of inventive step, a ground for opposition which had not been considered in the first decision). On the other hand, it only applies "in so far as the facts are the same" (see as an example T 1018/03, points 2.1 and 2.2 of the Reasons: further features were introduced into the claims after remittal in order to overcome inventive-step objections raised in the second appeal). The principle of res judicata is not limited to a situation of remittal for further prosecution but also applies in such a situation. Matter which has become res judicata is not open for reconsideration following remittal. Since this principle applies to all issues of fact which have been finally settled, it precludes a change of facts as contemplated by Article 111(2) EPC (T 843/91, OJ EPO 1994, 832, headnote and point 3.4.2 of the Reasons; T 1063/92, point 2.5 of the Reasons; T 153/93, points 2 and 3 of the Reasons). New facts, evidence or arguments seeking to cast doubt upon settled issues of fact cannot be considered. An example of this situation is decision T 308/14 (see headnote and points 1.2 and 1.3 of the Reasons): the first decision contained the finding of fact that the weight-average molecular weight in a claim was clear in terms of Article 84 EPC since, taking into account the evidence on file, it did not depend on the measurement method applied. Based on new documents introduced after remittal, the opposition division held that there was insufficiency arising out of ambiguity, namely the ambiguity of the weight-average molecular weight when measured according to different methods. The board held that this contravened the principle of res judicata which extended to any finding of fact that led to the decision remitting the case. See, however, the diverging decision T 1545/08 (points 11 and 12 of the Reasons).

4.6 The appellants are correct in stating that the principle of res judicata was narrowly defined in decision T 167/93 (OJ EPO 1997, 229, point 2.5 of the Reasons). However, decision T 167/93 was not concerned with the situation of an intervention after remittal of the case by a board of appeal, but with a cross-procedural res judicata effect (see T 167/93, point VI of the Facts and Submissions and points 2.6 to 2.10 of the Reasons). The definition of res judicata given in decision T 167/93 also deals with this situation. It is based on the doctrine of estoppel (T 167/93, point 2.5 of the Reasons) which operates as a defence of a party in subsequent separate proceedings between the same parties if facts or issues which have previously been judicially determined in a final manner are raised again. The doctrine appears not to relate specifically to circumstances as in the present case, i.e. the effect of a decision of an appeal board on a third party joining the resumed opposition proceedings after partial settlement of the issues between the parties to the appeal. In the present situation, it is important to take into account that opposition and opposition appeal proceedings require a decision on the form in which a patent can be maintained. Such a decision not only binds the parties to these proceedings, but its effect is erga omnes (T 598/98, point 1.7 of the Reasons). The nature of opposition and opposition appeal proceedings therefore does not support the view that a matter finally settled by an appeal decision remitting the case to the opposition division for further prosecution only binds the parties to the appeal proceedings and does not prejudice an intervener that only becomes a party to the opposition proceedings subsequent to the remittal of the case. The result of applying the principle of res judicata depending on the party status in the appeal proceedings leading to remittal would be absurd. The adjudged matter had to be accepted by the initial parties, and the opposition division had no power to re-open such matter in respect of those parties, whereas interveners would be allowed to disregard the final findings of the decision remitting the case to the opposition division and start opposition proceedings anew. However, in opposition proceedings it is not possible to take separate decisions for different parties on the form of the patent to be maintained. It is also not possible, as suggested by appellant-opponent 2, to conceptually separate the opposition proceedings into two different parts, the first one being the original opposition and the second one opposition proceedings including the interveners. A European patent can only be the subject of one common opposition procedure (Article 99(3) EPC; T 863/96, point 2). The filing of oppositions by different opponents or interveners does not lead to separate opposition proceedings for each party, not even conceptually (T 694/01, OJ EPO 2003, 250, point 2.19). In the absence of pending opposition proceedings, assumed infringers may also not initiate opposition proceedings on their own by filing a notice of intervention. They can only intervene in opposition and opposition appeal proceedings initiated by another party. For these reasons, the rationale of T 167/93 cannot, in the board's opinion, be extended to the situation at hand. The principle of res judicata must have effect for all parties to the resumed opposition proceedings, even those that were not party to the previous appeal proceedings. Also, the opposition division and, on subsequent appeal, the board are bound by the substance of a remitting decision in that they are prevented from re-opening the settled issues (see T 694/01, OJ EPO 2003, 250, point 2.10 of the Reasons; T 308/14, catchword).

4.7 In view of the above, the board considered whether the object and purpose of Article 105(1) EPC might justify and constitute an exception to both the principle of res judicata and the binding effect under Article 111(2) EPC.

4.7.1 Article 105(1) EPC on the one hand and the principle of res judicata and Article 111(2) EPC on the other hand involve conflicting considerations. As set out above, the purpose of Article 105 EPC is to ensure efficient use of the judicial system by preventing parallel national proceedings and to avoid contradictory decisions on the validity of European patents in the EPO and national courts. The principle of res judicata and Article 111(2) EPC, on the other hand, serve legal certainty, i.e. the general interest of the public that legal disputes be terminated within reasonable time. However, these principles also prevent re-litigation of issues of fact or law that have already been determined by a court, and thereby avoid a waste of judicial resources and inconsistent decisions. Whereas the purpose of Article 105 EPC speaks in favour of allowing the assumed infringer to make their full case against the opposed patent and make use of all available means of attacking the patent, the principle of res judicata and Article 111(2) EPC contradict this. These principles appear irreconcilable and the question is therefore which principle should prevail.

4.7.2 The appellants relied on decision G 1/94 (OJ EPO 1994, 787, point 13 of the Reasons) and argued that the Enlarged Board of Appeal had acknowledged an intervener's right to defend its case in full even at the appeal stage of proceedings. Decision G 1/94 is concerned with an intervention of the assumed infringer when the proceedings have reached the appeal stage, and is confined to the finding that such intervention is admissible "during pending appeal proceedings and may be based on any ground for opposition under Article 100 EPC". Both the procedural situation and the point of law considered in decision G 1/94 differ from the factual and legal issues in the present case. As regards the procedural situation, it is clear from the reference to "pending appeal proceedings" that decision G 1/94 considered a situation where a presumed infringer intervenes before a decision is taken at the appeal stage. It thereby built on and added to decision G 4/91 (OJ EPO 1993, 339, corrected translation, 707) in which the Enlarged Board held that a notice of intervention filed during the two-month period for appeal provided by Article 108 EPC has no legal effect if no appeal is filed by a party to the opposition proceedings before the opposition division (G 4/91, headnote 4 and point 7 of the Reasons). The admissibility of an intervention thus requires that no final decision has been taken either by the opposition division in the absence of an appeal (G 4/91, headnote 2 and 3) or by a board of appeal in the event of such appeal. The statement that interveners should not be prevented from making use of all available means of attacking the patent has to be read in this context. This statement does not extend to a situation in which opposition appeal proceedings have been determined and completed in part or in full by the issuing of a decision. It is also to be noted that the order and the headnote of decision G 1/94 refer to a "new ground for opposition" and not to "all available means of attacking the patent" as stated in point 13 of the Reasons. The narrow order appears to address a potential conflict with decision G 10/91 mentioned in said passage. From this reference it can be inferred that the Enlarged Board of Appeal, in addition to the admissibility of an intervention during appeal proceedings as such, addressed as a further procedural issue an exception to the constraint on introducing new grounds in appeal proceedings as established by decision G 10/91 (OJ EPO 1993, 420, headnote 3 and point 18 of the Reasons, requiring the approval of the patent proprietor). But even if the introduction of a new ground for opposition is merely seen as exemplifying the absence of any limitations to the introduction of new matter, this ruling is still confined to the situation that no decision has been taken on appeal. Indeed, the Enlarged Board of Appeal also held that the case should be remitted to the department of first instance for further prosecution should a new ground for opposition be introduced in "ordinary" appeal proceedings (G 1/94, point 13 of the Reasons). For this reason, and because the Enlarged Board of Appeal had refrained from commenting on further aspects of an intervention during the appeal proceedings, the rationale of decision G 1/94 cannot be extended to the issues of the present case and cannot support the appellants' view that G 1/94 establishes a right of the interveners to present the full case in opposition proceedings after remittal under Article 111(1) EPC which prevails over the principle of res judicata and the binding effect according to Article 111(2) EPC.

4.8 Allowing interveners in opposition proceedings after a remittal under Article 111(1) EPC for further prosecution to make "use of all available means of attacking the patent" (G 1/94, OJ EPO 1994, 787, point 13 of the Reasons) and, in particular, to challenge issues which have been finally determined in the remitting decision of an appeal board would lead to a situation which cannot be reconciled with the provisions of the EPC and generally applicable principles of procedural law, and cannot be justified by the interest in enabling the validity of a European patent which is the subject of infringement proceedings before a national court to be determined centrally within opposition proceedings before the EPO.

4.8.1 As discussed in decision T 694/01 (OJ EPO 2003, 250, point 2.18 of the Reasons), an intervention in opposition proceedings after remittal would de facto constitute a means of appeal against the board's remitting decision if interveners were allowed to raise factual and legal issues finally settled therein. However, only parties to the proceedings leading to the contested decision who are adversely affected thereby have the right to initiate appeal and review proceedings and can become a party thereto (Articles 107 and 112a(1) EPC; G 2/19, OJ EPO 2020, 87, point B.II.4 of the Reasons; G 3/04, OJ EPO 2006, 118, point 6 of the Reasons). If the assumed infringer validly intervenes in the opposition proceedings after remittal by an appeal board, he acquires the status of an opponent (Article 105(2) EPC) and thus a party to these proceedings, but nothing more. Lacking party status in the appeal proceedings which lead to the remittal prior to the intervention, an intervener joining the resumed opposition proceedings has no standing to challenge, by whatever means of redress, the matter finally adjudged between the other parties in the appeal decision (see G 2/19, OJ EPO 2020, 87, points B.II.4 and 5 of the Reasons). Although this has not been argued by the appellants, the board also notes, for sake of completeness, that neither the wording nor the object and purpose of Article 105 EPC suggests that an intervener in opposition proceedings after remittal by a board of appeal retroactively acquires the status of an appellant to the previous appeal proceedings (see G 3/04, OJ EPO 2006, 118, points 5 and 6 of the Reasons, which denies such a status even in the event of an intervention being filed during pending appeal proceedings). These remain proceedings inter alios. But even if such a creative interpretation of Article 105 EPC was accepted in order to give full effect to the legislative purpose of Article 105 EPC, such interpretation could only pave the way for a petition for review under Article 112a EPC as the sole available means of redress against a final decision by a board of appeal. The creation of an additional remedy aimed at reviewing a decision of a board of appeal would in any case exceed the application of general procedural principles (Article 125 EPC) and the powers of the boards of appeal (see G 1/97, OJ EPO 2000, 322, point 3(a) of the Reasons; T 402/01 of 4 October 2005, point 1.2 of the Reasons; T 883/06, point 2 and 3 of the Reasons).

4.8.2 However, the appellants did not claim a right to review decision T 950/13, but argued that there could be no restriction on the matter raised in an intervention, even when filed in opposition proceedings following a remittal, since an intervener was not restricted to the grounds of the opposition(s) instituting the proceedings. Such approach, which gives an absolute character to the right to expand on the factual and legal framework of the initial opposition, cannot be accepted. Exceeding the framework of an initial opposition is not the same as re-opening issues raised therein and decided by the board of appeal. In the latter case, the opposition division would have to disregard a decision of a board of appeal which sets aside the opposition division's previous decision, and decide on the matter again. The opposition division would thus become judge in its own cause. This is without doubt irreconcilable with fundamental principles of procedural law. Even leaving aside the fact that submissions by the interveners which call into question the decision de facto aim at the revision of a board's decision contrary to G 1/97 (OJ EPO 2000, 322, point 6 of the Reasons), the appellants' approach is also unacceptable as it either leads to contradicting decisions within the same opposition procedure or a waste of time and resources. The board therefore agrees with decision T 694/01 that there "is nothing in the EPC to suggest that the intervention of an assumed infringer opens a new stage of proceedings which invalidates binding results of the proceedings to date" (T 694/01, OJ EPO 2003, 250, point 2.18 of the Reasons).

4.9 In the event of an assumed infringer intervening in opposition proceedings after remittal to the opposition division for further prosecution, the intervener must for the above reasons accept the case as it stands when joining it (T 694/01, OJ EPO 2003, 250, point 2.20 of the Reasons). In such a case, opposition proceedings within the meaning of Article 105 EPC exist only to the extent that the examination of the grounds for opposition has not been completed by the issuing of a decision of the board of appeal. The extent to which opposition proceedings are completed is determined by the principle of res judicata and the binding effect pursuant to Article 111(2) EPC (see above). An assumed infringer can validly intervene in opposition proceedings resumed after remittal of the case under Article 111(1) EPC to the extent that these proceedings are still existing, and is not entitled to intervene in matters finally adjudicated which are no longer part of the opposition proceedings (T 694/01, point 2.20 of the Reasons; T 898/07, point 3.1 of the Reasons).

4.10 In the case at hand, the grounds of opposition of added matter and sufficiency of disclosure have been finally determined in decision T 950/13. These grounds are therefore not open to an intervention and can be considered neither by the opposition division nor by the board on appeal. As set out above, due to the principle of res judicata, it is not possible to change the facts underlying the decision T 950/13 even if this change is acceptable in view of the ratio decidendi.

4.11 Referral

According to Article 112(1)(a) EPC, a referral should be made if a board considers that a decision of the Enlarged Board of Appeal is required to ensure uniform application of the law or when a question of fundamental importance arises.

It is thus clear that a referral to the Enlarged Board is a matter of discretion. Whilst it is clear that the point of law of the scope of interventions filed in resumed opposition proceedings after remittal for further prosecution that has been argued in this case is important, it is equally evident that the question of law can be answered on the basis of the detailed analysis in decision T 694/01. Accordingly, a decision on this point by the Enlarged Board is not required. As set out in detail above, the finding is not in conflict with decision G 1/94 (OJ EPO 1994, 787) relied on by the opponents, as said decision is concerned with a procedurally distinct situation. Moreover, it has been explained why the board considers that there are no decisions conflicting with decision T 694/01. Therefore there is also no need for a referral in order to ensure uniform application of the law.

For these reasons there is no necessity to refer a question in this regard to the Enlarged Board of Appeal as suggested by appellant 2.