T 1760/11 ((-)-Omeprazole Mg/ASTRAZENECA) of 16.11.2012

European Case Law Identifier: ECLI:EP:BA:2012:T176011.20121116
Date of decision: 16 November 2012
Case number: T 1760/11
Petition for review: R 0010/13, R 0011/13, R 0013/13, R 0005/13, R 0012/13, R 0009/13
Application number: 00108480.5
IPC class: C07D 401/12
A61K 31/44
A61P 1/04
Language of proceedings: EN
Download and more information:
Decision text in EN (PDF, 466.625K)
Documentation of the appeal procedure can be found in the Register
Bibliographic information is available in: EN
Versions: Unpublished
Title of application: Magnesium salt of the (-)-enantiomer of omeprazole and its use
Applicant name: AstraZeneca AB
Opponent name: Hexal AG
Teva Pharmaceutical Industries
Mepha AG
STADA Arzneimittel AG
Pinewood Laboratories Limited
ETHYPHARM
Actavis Group hf.
Lupin Limited
Zentiva a.s.
Generics [UK] Limited
Ratiopharm GmbH
lA Pharma GmbH
Hexal Pharma GmbH
Hörnchen, Ulrich, Dr.
Board: 3.3.01

Headnote

-
Relevant legal provisions:
European Patent Convention Art 24(3)
European Patent Convention Art 54
European Patent Convention Art 56
European Patent Convention Art 87
European Patent Convention Art 100(b)
European Patent Convention Art 100(c)
European Patent Convention Art 112a(2)(c)
European Patent Convention Art 113(1)
European Patent Convention Art 123(2)
European Patent Convention R 106
Rules of procedure of the Boards of Appeal Art 12(2)
Rules of procedure of the Boards of Appeal Art 12(4)
Rules of procedure of the Boards of Appeal Art 13(1)
Keywords: Admissibility of first partiality objection (yes), second (no)
Res judicata (no)
Main request, added matter (yes)
Auxiliary request 1, allowable
Added matter (no)
Sufficiency (yes), starting material retrievable from Chemical Abstracts
Novelty (yes), specific salt
Inventive step (yes), post-published evidence (yes), unexpected advantage
Referral to the Enlarged Board of Appeal (no)
Objection under Rule 106 EPC dismissed
Catchwords:

-

Cited decisions:
T 0206/83
T 0296/87
T 0292/92
T 0167/93
T 0990/96
T 1028/96
T 0967/97
T 0609/02
T 0401/04
T 0591/04
T 1329/04
T 0021/08
Citing decisions:
T 1677/11
T 0833/11

Summary of Facts and Submissions

I. European patent No. 1 020 461 was filed as patent application number 00 108 480.5. It is a divisional application of the parent application EP-A-0 652 872, based on international application WO 94/27988 (document (23)), filed on 27 May 1994 and claiming priority of 28 May 1993 from the Swedish patent application number 9301830-7 (document (28)). It was granted on the basis of thirteen claims.

Independent claim 9 as granted reads as follows:

"9. A magnesium salt of (-)-5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)-methyl]sulfinyl]-1H-benzimidazole ((-)-omeprazole) with an optical purity of >= 99.8% enantiomeric excess (e.e.)."

Independent claim 1 is directed to the use of this salt "for the manufacture of a medicament for the inhibition of gastric acid secretion". Claims 2 to 8 are dependent claims; in claim 5, the disease to be treated is specified to be "reflux esophagitis".

Claims 10 to 13 read as follows:

"10. A salt as claimed in Claim 9 for use in therapy.

11. A salt as claimed in Claim 10 for use in the treatment or prophylaxis of a condition as defined in any one of Claims 3 to 8.

12. A salt as claimed in any one of Claims 9 to 11 which is crystalline.

13. A pharmaceutical composition of a salt as claimed in any one of Claims 9 to 12 together with a pharmaceutically acceptable carrier."

II. Oppositions were filed and revocation of the patent in its entirety requested pursuant to Articles 100(c), 100(b) and 100(a) EPC (lack of novelty and inventive step).

III. The following documents were cited inter alia during the opposition/appeal proceedings (note: where documents are numbered in the format (x-y), this designates annex y attached to document x):

(1) DE-A-40 35 455

(1A) Translation of document (1), received 28 May 2010

(2) EP-A-0 124 495

(3) P Erlandsson et al., J. Chromatogr., 1990, 532,

305 - 319

(6) S Allenmark et al., Anal. Biochem., 1984, 136,

293 - 297

(7) B Kohl et al., Poster, 4th International Symposium

of Chiral Discrimination, Sept. 19-22, 1993,

Montreal, Quebec, Canada, Abstract No. 35

(8) T Uematsu et al., J. Pharm. Sci., 1994, 83(10),

1407 - 1411

(9) WO 94/24867

(11) Comprehensive Medicinal Chemistry, Ed. C Hansch,

Pergamon Press, Oxford, 1990, 198-205

(12) Chirality, 1992, 4, 338 - 340

(14) H Nagaya et al., Biochem. Pharmacol. 1991, 42(10),

1875 - 1878

(17-6) E Carlsson et al., Chem. Brit., May 2002 ,

42 - 45

(18) Declaration of E. Magnus Larsson and Exhibits

(originally received 10 November 2008, as cited in

Annex 1 to decision under appeal)

(20) Declaration of Dr Bernhard Kohl and Exhibits

(originally received 10 November 2008, as cited in

Annex 1 to decision under appeal)

(21) EP-B-0 652 872

(23) WO 94/27988

(28) SE 9301830-7 (priority document of patent in suit)

(32) I Marle et al., J. Chromatogr., 1988, 456,

323 - 336

(33) K M Williams, "Molecular Asymmetry and Its

Pharmacological Consequences", in Advances in

Pharmacology, 1991, Vol. 22, pages 57 - 135

(34) T Andersson et al., Ther. Drug Monit., 1990, 12,

415 - 416

(36) EP-A-0 005 129

(37) EP-B-0 166 287

(38) P Lindberg et al., Med. Res. Rev., 1990, 10(1),

1 - 54

(42) W H De Camp, Chirality, 1989, 1, 2 - 6

(47) (= document (101-14)), P J Kahrilas et al.,

Aliment. Pharmacol. Ther., 2000, 14, 1249 - 1258

(80) Declaration of Tommy Andersson and Exhibits

(submitted with patentee's letter dated

6 April 2011, received 7 April 2011)

(83) WO 88/03921

(84) Chemical Abstracts reference to document (83)

(submitted with patentee's letter dated

10 December 2010, received 13 December 2010)

(87) Swedish MPA Monograph for Lansoprazole (published

June 1993, submitted with patentee's letter dated

10 December 2010, received 13 December 2010)

(101) Declaration of Dr Nimish Vakil and Exhibits

(submitted with patentee's letter dated

6 April 2011, received 7 April 2011)

(101-12) K Röhss et al., Digest. Dis. Sci., 2002, 47(5),

954 - 958

(101-16) C J Lightdale et al., Digest. Dis. Sci., 2006,

51, 852 - 857

(102) NDA 21-153, page 174, received 25 February 2011

(103) NDA 21-153, Medical Review(s), pages 2 - 9,

received 25 February 2011

(104) Second Declaration of Tommy Andersson and

Exhibits (submitted with patentee's letter dated

6 April 2011, received 7 April 2011)

(104-D) D J Hetzel et al., Gastroenterology, 1988, 95,

903 - 912

(105) Declaration of Professor Ernst Kuipers and

Exhibits (submitted with patentee's letter dated

6 April 2011, received 7 April 2011)

(105-3) M Hassan-Alin et al., Eur. J. Clin. Pharmacol.,

2005, 60, 779 - 784

(105-6) E C Klinkenberg-Knol et al., Aliment. Pharmacol.

Ther., 1990, 4, 485 - 495

(120) Enantiomers, Racemates, and Resolutions,

Krieger Publishing Company, 1991, 423 - 434

(146) (= document (101-6)) T Lind et al., Aliment.

Pharmacol. Ther., 2000, 14, 861 - 867

(147) T Andersson et al., Clin. Pharmacokinet., 2001,

40(6), 411 - 426

(148) T Andersson et al., Pharmacogenetics, 1992, 2,

25 - 31

(149) Auterhoff, Knabe, Höltje, Lehrbuch der

Pharmazeutischen Chemie, 1991, 10 - 11

(150) E Mutschler, Arzneimittelwirkungen, 1991, 48 - 49

(151) R H Levy et al., Pharm. Res., 1991, 8(5),

551 - 556

(152) W R Crom, Am. J. Hosp. Pharm., 1992, 49(Suppl. 1),

S9 - S14

(153) C G Regårdh et al., Ther. Drug Monit., 1990, 12,

163 - 172

(154) P N Maton, New Engl. J. Med., 1991, 324(14),

965 - 975

(164) B Kohl et al., J. Med. Chem., 1992, 35,

1049 - 1057

(168) I M Gralnek et al., Clin. Gastroenterol. Hepatol.,

2006, 4, 1452-1458

(171) C W Howden et al., Gastroenterology, 1986, 90(5),

part 2, 1466

(174A) K Miwa et al., Jpn. Pharmacol. Ther., 1990, 18,

3413-3435

(174B) English translation of document (174A) received

4 June 2012

(179) Second declaration of Sverker von Unge,

dated 29 August 2012, and Exhibits, filed by the

appellant with letter dated 7 September 2012

(180) Third declaration of Marcus F Brackeen,

dated 20 October 2012, and Exhibits, filed by

respondent 2

IV. The appeal lies from the decision of the opposition division revoking the patent under Article 101(2),(3)(b) EPC, based on a main request, namely, the claims as granted, auxiliary requests 1 to 4 filed with letter dated 6 April 2011, and auxiliary request 5 filed at oral proceedings before the opposition division on 9 June 2011.

Auxiliary request 1 differs from the claims of the main request in that "or prophylaxis" has been deleted from claim 11 (cf. above point I).

With respect to the main request, the opposition division found in favour of the appellant on all issues raised (namely, res judicata, double patenting, Article 100(c) EPC, entitlement to priority date, Article 100(b) EPC, and novelty), apart from the question of inventive step. In its analysis of inventive step with respect to the subject-matter of claim 9, the opposition division identified document (1) as representing the closest prior art. Two definitions of the problem to be solved were considered, namely, the provision of alternative compounds to those of document (1), or with an improved optical purity. The solution proposed to these problems was found to be obvious in view of the teaching of document (2), which disclosed that the magnesium salt of omeprazole was particularly stable, and document (120), which detailed the common general knowledge regarding the purification of enantiomers by means of salt formation and recrystallisation.

The same reasoning applied to auxiliary request 1.

V. The appellant (patentee) lodged an appeal against this decision and filed grounds of appeal. Accelerated processing of the appeal was requested in view of ongoing litigation in several countries.

VI. In a communication dated 19 December 2011, the board informed the parties that it had decided to grant the appellant's request for accelerated processing and set out a procedural timetable.

VII. Responses to the grounds of appeal were received from respondents 1 to 4 and 6 to 13 (opponents 1 to 4 and 6 to 13).

VIII. In a communication sent as annex to the summons to oral proceedings dated 6 July 2012, the issues to be discussed at oral proceedings were summarised. It was noted that a particularly contentious point was the choice of closest prior art.

IX. With letter dated 7 September 2012, the appellant filed an annex containing further submissions and a declaration numbered as document (179).

X. In reply, respondent 2 filed a declaration numbered as document (180) with letter of 19 October 2012, and requested that document (179) not be admitted into the proceedings. Respondents 1, 9, 10 and 12 also put forward the same request, whereby respondent 10 additionally requested, with letter of 7 November 2012, that the submissions of the appellant filed with letter of 7 September 2012 not be admitted into the proceedings.

XI. Oral proceedings were held before the board from 13 to 16 November 2012.

Towards the end of the third day of oral proceedings, on 15 November 2012, after the parties had been informed that the board had come to the conclusion that the subject-matter of auxiliary request 1 met the requirements of the EPC, respondents 1 to 4, 6, 7, and 9 to 13 requested the referral of the following two questions to the Enlarged Board of Appeal:

| | |

| "1. | In case where there is more than |

| | one feasible starting point, |

| | is it admissible, contrary to |

| | T 21/08, to find an inventive step |

| | by applying the problem solution |

| | approach starting from only |

| | one of these starting points |

| | without considering the others? |

| | |

| 2. | In particular, is it admissible |

| | in a case relating to a patent |

| | granted on a divisional application, |

| | to ignore the starting point |

| | identified by the Appeal Board |

| | in the technically closely |

| | related parent case (here: T 401/04)?" |

| | |

As an auxiliary request, the same respondents requested to be given the opportunity to address inventive step of the subject-matter of auxiliary request 1 starting from document (1) as the closest prior art.

After both requests had been rejected, respondents 1 to 4, 6, 7, and 10 to 13 raised an objection under Rule 106 EPC in conjunction with Article 112a(2)(c) EPC, which was formulated in writing as follows:

"We hereby raise an objection under R. 106 EPC since we were denied the opportunity to address inventive step starting from D1 as closest prior art during oral proceedings. This constitutes a violation of the right to be heard."

Owing to the fact that the chairman of the board had denied their request for an adjournment of oral proceedings until the next day in order to formulate said objection under Rule 106 EPC, respondents 1 and 12 objected to the chairman of the board under Article 24(3) EPC because of suspected partiality (first partiality objection). On the following day, after this objection was found to be admissible, the original chairman was replaced by his alternate for the purpose of deciding on allowability (Article 24(4) EPC). This matter is the subject of a separate decision.

On 16 November 2012, during the debate on the allowability of the first partiality objection, the representative of respondent 6 raised a second objection of suspected partiality under Article 24(3) EPC against the original chairman, based on the following allegations: The original chairman had previously been employed at Cabinet Regimbeau for eight years ending on 30 June 1999, and had also acted for respondent 6 during this time; the circumstances of his departure from Cabinet Regimbeau had given rise to concern. The representative of respondent 6 further argued that she could not have raised this objection earlier since she had only received the information that morning from her colleagues at Cabinet Regimbeau.

After rejection of the first partiality objection by decision of 16 November 2012, oral proceedings were resumed with the original chairman. The original representative of respondent 6 was then no longer present, but had given a sub-authorisation to the representative of respondents 3 and 11. The latter stated that he had been instructed that respondent 6 maintained its objection of suspected partiality, but that he had not been provided with any further information in this respect.

XII. The appellant's arguments, insofar as they are relevant to the present decision, may be summarised as follows:

Regarding the principle of res judicata, the appellant argued that there was no binding effect of decision T 40l/04 issued with respect to the parent patent (document (21)), since the subject-matter of the present claims and the facts of the case differed from those considered therein. The additional feature of ">= 99.8% enantiomeric excess" was technically meaningful, since it defined an extremely high level of optical purity which reflected the intended use of the claimed salt as a drug product and provided a clear distinction over the already-existing drug product based on racemic omeprazole. The public expectation must therefore be that the present appeal would be considered on its merits, independently from the parent case.

In connection with the ground of opposition raised under Article 100(c) EPC, the appellant argued that the magnesium salt of (-)-omeprazole was individualised as compound IIb on page 3 of document (23). The restriction to one of the preferred salts explicitly disclosed did not provide the skilled person with any additional information, and there had been no reformulation of the problem to be solved. The optical purity of >= 99.8% e.e. and therapeutic uses disclosed in document (23) clearly applied to all salts disclosed, including compound IIb. Furthermore, the crystallinity of the final salt compounds was an optional feature.

Concerning the term "prophylaxis" employed in claim 11 of the main request, the appellant submitted that the skilled person would understand that the inhibition of gastric acid secretion would inevitably prevent the related diseases from occurring in the future. The claimed use in the prophylaxis of the conditions listed was therefore implicitly disclosed in document (23).

In relation to the question of entitlement to priority, the appellant argued that the same reasoning as that advanced with respect to Article 100(c) EPC applied.

The appellant further submitted that the objections under Article 100(b) EPC were unfounded since the skilled person would have no difficulty in preparing the claimed salt, and using it to treat the claimed conditions. A synthesis of the N-chloromethylated starting material had been readily retrievable from the Chemical Abstract database, as confirmed by documents (83) and (84), and the criteria for correctly assessing common general knowledge as listed in the "Case Law of the Boards of Appeal of the EPO", 6th edition 2010, I.C.1.5 were fulfilled. Moreover, the measurement of optical purity was entirely routine at the priority date of the opposed patent, and such techniques were disclosed for omeprazole, for example, in documents (6) and (32).

On the question of novelty, the appellant submitted that the subject-matter claimed was novel over document (1) since the latter did not disclose any specific salt of (-)-omeprazole.

Turning to the issue of inventive step, the appellant

argued that document (11) or alternatively document (2) represented more appropriate closest prior art documents than document (1) under the problem-solution approach, since they were reflective of the real world situation that all those working in the field faced at the priority date of the patent in suit, namely, improving on omeprazole. This problem was also addressed in more detail in paragraph [0002] of the patent in suit. More specifically, the problem of interindividual variation referred to therein related to the phenomenon observed to affect 30 to 50% of the patient population, for which omeprazole had proved to be ineffective or less effective than in other patients at clinical doses. That this was a well recognised problem in the art was confirmed inter alia by documents (11), (104), paragraphs 17 to 20, and (105), paragraphs 8 to 10.

In contrast, the choice of document (1) as the closest prior art was based on hindsight, since this document was focused on the resolution of pyridylmethyl benzimidazole sulfoxides into their enantiomers, and did not look into their therapeutic properties, let alone any benefit associated therewith. The skilled person would therefore not have regarded document (1) to be a suitable starting point for drug development. This would also go against the prevailing state of the art, in which the efforts to provide improved proton pump inhibitors (PPIs) had exclusively been focused on modifying the structural scaffold of omeprazole.

In any case, document (1) should not be taken as the closest prior art since it was non-enabling. In other words, the skilled person would not have been able to use the process disclosed therein to separate the enantiomers of omeprazole in a satisfactory way, reproducibly and without undue burden, or in any form that could be considered to be worth taking further. Whilst accepting that the first step, the reaction of the racemate with the chiral auxiliary, was capable of leading to some enrichment, up to a diastereomeric excess of 92% at best, the appellant submitted that the second hydrolysis/work-up step was intrinsically non-reproducible because the conditions were too severe for a highly acid-labile molecule like omeprazole. The scant description provided in document (1) was insufficient to allow the skilled person to successfully reproduce this step without undue burden. This was confirmed by the contemporaneous report document (18) describing the attempts by the patentee to reproduce document (1). Further confirmation could be derived from document (20) and the attached laboratory notebook pages recording the experimental results on which document (1) was based. It could be derived therefrom that, at very best, an enantiomer of omeprazole had been obtained with 90% e.e., at low yields and as an unpurifiable material. The respondents' evidence in this respect should be disregarded since it had been produced with the benefit of intervening knowledge and could moreover not be regarded as an accurate reproduction of the process according to document (1). In fact, in example 6 of document (1), (+)-omeprazole had only been obtained as an amorphous material which could not be purified by conventional means, within the meaning of decision T 990/96. Contrary to assertions by the respondents, salt formation and recrystallisation were not part of the resolution process disclosed in document (1), and the methods disclosed in document (120) did not represent common general knowledge in the relevant field. Furthermore, such a method could not be viewed as an obvious choice.

The appellant defined the problem to be solved, starting from document (2) as the closest prior art, as lying in the provision of a PPI having an improved therapeutic profile, in particular with a lower degree of interindividual variation of therapeutic effect. The solution proposed in claim 9 of the patent in suit related to the active substance in the medicament marketed under the brand name Nexium. A number of documents were referred to as demonstrating that this subject-matter successfully solved the problem posed, in particular, document (101), and its attachments 6, 12, 14 and 16, as well as documents (80), (105) and its annex 3, and (147). These comparative studies demonstrated that the improvements relied upon were actually achieved and attributable to the distinguishing feature of the invention, that is, the presence of omeprazole as its (-)-enantiomer with an optical purity of >= 99.8% e.e.

The solution claimed was not rendered obvious by any of the documents in the proceedings. Thus, document (2) itself did not contain any reference to single enantiomers. According to document (3), the enantiomers of omeprazole were equipotent. This was to be expected given the fact that PPIs were known to be prodrugs that were chemically converted at their site of action to achiral sulfenamides. A similar teaching could be derived from document (11). Document (1) also did not offer any prospect of a therapeutic improvement for single PPI enantiomers. Confirmation of this was provided by documents (164) and (7) for pantoprazole, and by document (87) for lansoprazole. There was therefore no pointer towards developing a single enantiomer of any PPI as a drug in the expectation of obtaining a superior product.

Finally, the appellant argued that there was no reason to put a question to the Enlarged Board of Appeal regarding the application of the problem-solution approach, since there was no divergent case law (cf. above point XI). Nor had the respondents' right to be heard been violated, since all parties had been allowed to fully discuss the issue of inventive step, based on the problem-solution approach.

XIII. The respondents' arguments, insofar as they are relevant to the present decision, may be summarised as follows:

Respondent 9 argued that the issue of inventive step has been decided with res judicata effect in the parent case T 401/04. The six criteria identified in T 167/93 were fulfilled, in particular criterion (d), since the issues of fact were the same in both cases. Specifically, in T 401/04, it had been decided that the subject-matter of claim 15 of the main request was not based on an inventive step, starting from document (1) as the closest prior art. The only additional feature in claim 5 of the present patent in suit was that defining the optical purity to be >= 99.8% e.e. However, this feature could not serve to distinguish the claimed subject-matter over that of document (1), in view of established case law of the boards of appeal. Thus, according to decision T 990/96, if conventional methods existed for purifying a low molecular compound, said compound was made available in all grades of purity. As had correctly been analysed in the decision under appeal, with reference to document (120), salt formation and recrystallisation was one such conventional method available to the skilled person for increasing the optical purity of enantiomers. Therefore, in the present case, document (1) made (-)-omeprazole and its salts with bases available to the public in all levels or grades of chemical and optical purity, including the level of >= 99.8% e.e. now claimed. Thus, even though there was a verbatim difference in the claims under consideration, it was clear that the facts of the case were the same in substance, and that the feature now added would not have altered the reasoning given in T 401/04, in particular with respect to the choice of closest prior art. If anything, the additional feature strengthened the selection of document (1) over document (2), as the latter was silent on the subject of enantiomers. Consequently, since the question of inventive step of the claimed invention had already been decided once in the opposition appeal proceedings T 401/04, this matter was no longer open to challenge in the present proceedings. A different decision would be contrary to the public interest in legal certainty.

The respondents disputed the appellant's submissions with respect to Article 100(c) EPC.

From a comparison of the subject-matter of claim 9 of the main request with the disclosure of document (23) it could be seen that several selections were required, namely, a selection from a list of various salts, the selection of the (-)-enantiomer of omeprazole over the (+)-enantiomer, and the combination thereof with the specific optical purity of >= 99.8% e.e.

In particular, from the first paragraph on page 4 of document (23), it was clear that the feature relating to the degree of optical purity of >= 99.8% e.e. was only disclosed in connection with production of crystalline salts, and more particularly crystalline sodium salts of the enantiomers of omeprazole, which were the only crystalline salts specifically disclosed in document (23).

In addition, the claimed subject-matter was based on further selections with respect to the specific medical uses, such as "reflux esophagitis" (claim 5).

These combinations of features from several originally disclosed lists were not directly and unambiguously derivable from document (23).

Furthermore, in document (23), it was not specified which of the enantiomers of omeprazole led to the alleged effect of reduced inter individual variation disclosed on page 1, lines 18 to 20, although it was self-evident that both enantiomers could not simultaneously exhibit the same advantage. Therefore, highly relevant information had been added in the patent in suit, owing to the selection of the (-)-enantiomer over the (+)-enantiomer of omeprazole, in connection with the corresponding passage in paragraph [0002].

A further objection was raised with respect to paragraph [0036] of the patent in suit. With the reference therein to "the optically pure compounds of the invention", the false impression was created that the racemisation experiments had been performed on a magnesium salt of (-)-omeprazole with an optical purity of >= 99.8% e.e. In contrast, the skilled person would understand the corresponding paragraph in document (23) to describe experiments starting with (-)-omeprazole with an undisclosed optical purity, or of 94% e.e., as prepared in Example 10.

Finally, claim 11 of the main request also contained added subject-matter owing to the presence of the term "prophylaxis". In document (23), this term was only disclosed in connection with specific inflammatory conditions, and not with respect to all the conditions now claimed.

All but the last of these objections also applied to auxiliary request 1.

Several objections under Article 100(b) EPC were raised by the respondents.

One objection raised related to the fact that the preparation of the claimed salt described in the patent in suit started from an N-chloromethylated omeprazole. However, no method for its preparation was disclosed therein, and it would be an undue burden for the skilled person to prepare this compound based on common general knowledge alone. Reliance on the contents of the Chemical Abstract database could not remedy this deficiency, as confirmed by decision T 206/83.

In addition, the patent in suit did not contain any information that would allow the skilled person to reliably determine the claimed parameter relating to the optical purity of >= 99.8% e.e. In the absence of such a method, the skilled person faced an undue burden when trying to determine whether unknown samples fell within the scope of claim 1.

Finally, it was argued, with reference to decision T 609/02, that the claimed subject-matter was insufficiently disclosed because the original application did not contain any evidence that (-)-omeprazole was the enantiomer leading to the alleged effect of reduced interindividual variation.

Respondent 6 maintained its objection of lack of novelty of the subject-matter of claims 1 and 9 of the auxiliary request 1 with respect to document (1), with reference to page 3, line 54 and page 6, lines 38 and 42 of this document.

Turning to the issue of inventive step, the respondents referred to decision T 401/04 for the parent patent, in which document (1) had been considered to be the closest prior art, rather than document (2). The respondents agreed with this conclusion. Thus, documents (1), (2) and (11) all aimed at the same objective of providing inhibitors of gastric acid secretion for therapeutic use, namely, the treatment of gastrointestinal diseases. In terms of structural features, document (11) did not disclose (-)-omeprazole or a magnesium salt thereof; document (2) disclosed the magnesium salt of racemic omeprazole, but did not provide any suggestion as to the presence of enantiomers or the separation thereof. In contrast, document (1) not only specifically disclosed the (-)-enantiomer of omeprazole, which was the active ingredient of the patent in suit, but also taught the formation of salts thereof with bases. With reference to the same arguments advanced by respondent 9 with respect to decision T 990/96 in the context of submissions on res judicata (see first paragraph of this section), the respondents argued that the degree of optical purity could not be considered to be a feature distinguishing the claimed subject-matter from that of document (1). The only difference between the claimed subject-matter and the disclosure of document (1) was thus the selection of the specific magnesium counter ion.

In this context, the respondents submitted that, contrary to the view of the appellant, the disclosure of document (1) was completely credible and in no way deficient, and must a priori be regarded as being enabling, as had been acknowledged in paragraph [0003] of the patent in suit itself. Since it was the appellant who was now alleging the contrary, it was also the appellant who carried the burden of proof in this respect. Neither documents (18) nor (20) met the required standard of proof to demonstrate that the clear technical teaching of document (1) was non-enabling. Thus, document (18) was of little value in this respect, since the experiments described therein did not implement the teaching of document (1), in particular, that the pH should be raised as rapidly as possible in the work-up step, a measure that was aimed at avoiding the mildly acidic conditions in which omeprazole was known to be unstable. Moreover, by the appellant's own admission, at least one of the experiments discussed in document (20) had been successful in synthesising (+)-omeprazole with an optically purity of about 90% e.e., by means of a method that was largely the same as that described in document (1). Thus, if anything, this evidence confirmed the workability of the procedure according to example 6 of document (1). Moreover, a number of respondents had independently provided experimental evidence demonstrating that document (1) was enabling.

Therefore, the respondents were of the opinion that document (1) was to be regarded as the closest prior art since it had the most relevant technical features in common with the subject-matter claimed. This document had also been cited in the patent in suit as relevant prior art.

The respondents further disputed that the "real world situation" would favour document (2) as closest prior art. This was not an objective criterion, and the appellant had painted a completely misleading picture in this respect. It was not the case that everybody working in the field of PPIs had been looking to go forward with omeprazole at the priority of the patent in suit. In fact, as confirmed by document (38) (pages 46 to 48), omeprazole had been known to be a very effective drug at the optimum daily dose of 20 to 40 mg. There was therefore no reason to improve thereon. The problem defined in the patent in suit was therefore an artificial one. In particular, the concept of "inter individual variation" was unclear, and it was not the case that it had been a generally recognised problem at the time. For example, the reference in document (11) to a variation of the inhibitory effects of omeprazole purely related to sub-therapeutic doses of 5 and 10 mg, as became clear from the corresponding reference [63], submitted as document (171). In fact, at the priority date of the patent in suit, it was a realistic and even promising approach to consider the isolated enantiomers as candidates for drug development.

In any case, it was clear that document (1) must at least be regarded as a feasible starting point, in view of the fact that this had been considered as the closest prior art in the parent case T 401/04 and in the decision under appeal. Therefore, an inventive step would also have to be demonstrated relative to this route before a positive conclusion could be reached (cf. penultimate paragraph of this section).

However, even were document (2) to be considered the closest prior art, the respondents submitted that the subject-matter of the patent in suit would not be based on an inventive step.

Concerning the problem to be solved as outlined in paragraph [0002] of the patent in suit, the respondents emphasised that this must be regarded as being purely speculative, since there was absolutely no evidence provided therein that any effect relating to an improved therapeutic profile or a lower degree of inter individual variation had actually been achieved. In fact, it was evident from document (17-6) that the pharmacokinetic properties of the two enantiomers had not even been studied in humans until 1994, and it must therefore be concluded that the alleged invention had not yet been completed at the claimed priority date. Since the patent in suit did not make the alleged effect plausible, in accordance with decision T 1329/04, any post-published evidence should not be taken into consideration when assessing whether the problem had been solved. The appellant could not have it both ways: if it were to be argued that the alleged effect was plausible, then the subject-matter claimed could not be based on an inventive step.

The respondents further criticised the evidence relied on by the appellant on several levels.

Firstly, the data did not represent a valid comparison, since the magnesium salt of (-)-omeprazole had not been compared with the magnesium salt of the corresponding racemic mixture, and no information had been provided as to whether the optical purity of the compounds used in the study fell within the claimed range of >= 99.8% e.e. It was further noted that the statistical significance of the findings with respect to interpatient variability had not been indicated in document (146).

Even if differences in bioavailability, gastric acid suppression and interpatient variability were to be accepted as having been demonstrated, the clinical relevance of these results would be questionable, in view of the contradictory results obtained in documents (47), (101-16) and (168), and in view of the doubts in this respect raised in documents (102) and (103).

Furthermore, the claims were not limited to human patients, and any advantage would not therefore be valid for the full scope claimed.

Even were it to be accepted that the problem defined in the patent in suit had been successfully solved, the subject-matter claimed would nevertheless not be based on an inventive step over document (2) as closest prior art document. A skilled person would namely have expected that one of the two enantiomers of omeprazole would have advantageous properties over the other and thus over the racemate, as had been confirmed in decision T 296/87. An inventive step could not be recognised on the basis of any effect to have emerged from obvious and routine tests. This assessment was not altered by the fact that, in the case of omeprazole, the species responsible for activity was achiral, since decision T 296/87 did not make a distinction between advantages resulting from pharmacodynamic or pharmacokinetic effects.

Indeed, the skilled person was well aware at the date of priority of the patent in suit that enantiomers may differ in their pharmacokinetic properties, that is, in their absorption, distribution, metabolism, and excretion (ADME) profiles, as could be seen from the textbook knowledge and reviews cited as documents (33) and (149) to (152). This general knowledge was also reflected in the recommendations of regulatory authorities that single enantiomers of racemic drugs should be investigated in this respect, as illustrated inter alia by documents (12) and (42); in document (42), it was stated to be "both good science and good sense to explore the potential for in vivo differences between these forms".

The skilled person would therefore have regarded it to be a real possibility that differences in pharmacokinetic properties would result in a better activity for one of the omeprazole enantiomers.

It was further noted that interindividual variation had been known to exist for omeprazole before the priority date of the patent in suit, in relation to pharmacokinetics and acid secretion (documents (153) and (154)). More specifically, it was also known, for example from documents (34) and (148), that there were poor and extensive metabolisers of omeprazole and that these groups co-segregated with polymorphic hydroxylation of S-mephenytoin. Furthermore, interindividual variation in the metabolism of racemic mephenytoin was known to result from the fact that the (S)-enantiomer of mephenytoin was metabolised differently in poor and extensive hydroxylators, whereas this was not the case for the corresponding (R)-enantiomer (see e.g. document (33), section III.B; document (34), Figure 1). The skilled person would therefore have had at least a reasonable expectation that enantioselective metabolism would also be the reason for variation amongst patients treated with racemic omeprazole. This knowledge provided a further incentive for a skilled person to investigate the single enantiomers of omeprazole in order to reduce variations between poor and extensive metabolisers of omeprazole.

Moreover, document (3) suggested possible differences between the enantiomers in the degree of plasma protein binding. The skilled person would expect this to lead to different effects of the enantiomers, particularly since the degree of binding of racemic omeprazole to proteins in human plasma was known to be about 95%.

Finally, the significance of differing pharmacokinetic properties of enantiomers had also already been recognised in the field of PPIs, as illustrated by documents (14) and (174) for lansoprazole, and further confirmed by documents (8) and (9). The lack of stereochemical difference in activity discussed in documents (3), (14) and (164) was based on experiments conducted in vitro, and none of these documents uttered an expectation that there would not be a difference between the two enantiomers in vivo.

The respondents therefore submitted that, starting from document (2), it would have been obvious to the skilled person to isolate the enantiomers of the magnesium salt of omeprazole, for example, according to the process of document (1), or by means of methods according to document (3) and related commercially available HPLC technology, and test these in order to identify the one having the better properties.

Returning to their submission that document (1) was at least to be seen as a feasible starting point, the respondents argued that the approach adopted by the board, namely, restricting the assessment of inventive step to an analysis starting from a single starting point, was at variance with established case law. In this context, the respondents highlighted a number of decisions, in particular T 21/08, but also inter alia T 967/97 and T 591/04. According to these decisions, if there was a choice of several workable routes which might lead to the invention, the rationale of the problem-solution approach required that the invention be assessed relative to all these possible routes, before an inventive step could be acknowledged. This case law had been ignored by the present board. Consequently, a referral to the Enlarged Board of Appeal would be appropriate in order to ensure a uniform application of the law (cf. above point XI).

Moreover, the board's decision to reject the respondents' request to be allowed to address inventive step of the subject-matter of auxiliary request 1 starting from document (1) as the closest prior art amounted to a violation of Article 113(1) EPC, since the respondents had not been given an adequate opportunity to present their full case on inventive step.

XIV. The appellant requested that the decision under appeal be set aside and, as its main request, that the patent be maintained as granted, or, alternatively, that the patent be maintained on the basis of one of the auxiliary requests 1 to 4 filed with the letter dated 6 April 2011 and received on 7 April 2011 or on the basis of auxiliary request 5 submitted on 9 June 2011. The appellant moreover requested that the respondents' further procedural requests be rejected.

Respondents 1 to 4, 6, 7, and 9 to 13 requested that the appeal be dismissed. Respondent 8 requested in writing that the appeal be dismissed.

Respondents 1 to 4, 6, 7, and 9 to 13 requested the referral of two questions submitted during oral proceedings on 15 November 2012 to the Enlarged Board of Appeal.

Respondents 1 to 4, 6, 7, and 9 to 13 requested to be given the opportunity to address inventive step of the subject-matter of auxiliary request 1 starting from document (1) as the closest prior art.

Respondents 1 and 12 raised an objection of partiality under Article 24(3) EPC with respect to the chairman on 15 November 2012.

Respondent 6 raised an objection of partiality under Article 24(3) EPC with respect to the chairman on 16 November 2012.

Respondents 1 to 4, 6, 7, and 10 to 13 raised an objection under Rule 106 EPC together with Article 112a(2)(c) EPC on 15 November 2012.

XV. At the end of the oral proceedings, the decision of the board was announced.

Reasons for the Decision

1. The appeal is admissible.

2. Admissibility of partiality objections

(Article 24(3) EPC, cf. above point XI)

2.1 The first partiality objection was raised as an immediate reaction to the fact that the chairman of the board denied the request of respondents 1 and 12 for adjournment of oral proceedings until the following day. The requirement of Article 24(3) EPC, second sentence, is therefore fulfilled, and said objection is thus considered to be admissible.

The request under Article 24(3) EPC was subsequently rejected in a separate decision pursuant to Article 24(4) EPC.

2.2 As regards the second partiality objection, the board notes that no reasons were given as to why the fact that the chairman had been employed at Cabinet Regimbeau over thirteen years previously should bias him against respondent 6 or any of the other parties, regardless of whether or not he had in fact acted for respondent 6 during his time there. A further assertion was made that the circumstances of the chairman's departure from Cabinet Regimbeau had given rise to concern. However, such vague and unsubstantiated allegations cannot support an objection of suspected partiality (cf. T 1028/96, OJ EPO 2000, 475, point 2). Moreover, since the board's composition had been notified to the parties together with the summons to oral proceedings, respondent 6 could have raised its second partiality objection earlier.

Consequently, this objection under Article 24(3) EPC is rejected as inadmissible.

3. Admissibility of document (179) and appellant's letter dated 7 September 2012

During the course of oral proceedings, the board, exercising its discretion pursuant to Article 13(1) of the Rules of Procedure of the Boards of Appeal (RPBA, see Supplement to OJ EPO 1/2012, 38 to 49), decided not to admit document (179), filed by the appellant with letter dated 7 September 2012, since its filing could not be justified as an appropriate reaction to a change of the factual circumstances. However, since this document turned out not to be relevant for the outcome of the present appeal, the detailed reasons for this decision need not be discussed further.

Respondent 10 further requested, with letter of 7 November 2012, that also the parts of the appellant's submissions of 7 September 2012 which were not concerned with document (179) not be admitted into the proceedings. However, as was conceded by respondent 10 in its letter, this "would appear to be no more than a repetition ... of arguments that have already been placed into the record by the Proprietors in previous submissions, notably in their statement of grounds of appeal". Consequently, the board sees no basis, in view of Articles 12(2), 12(4) and 13(1) RPBA, for not admitting said letter, nor is it evident what would be achieved by doing so. Therefore, the remaining parts of the appellant's submissions of 7 September 2012, that is, with the exception of the parts relating to document (179), were admitted into the proceedings.

4. Res judicata

Respondent 9 argued that the principle of res judicata was applicable under the circumstances of the present case, in view of previous decision T 401/04, issued by this board in a different composition in relation to opposition appeal proceedings for the parent patent (document (21)).

In order to assess the question of whether "the issues of fact are the same" in both cases, as argued by respondent 9 (cf. decision T 167/93 (OJ EPO 1997, 229), point 2.5, criterion (d)), it is first necessary to compare the subject-matter claimed in the patent in suit with that claimed in document (21). Thus, the claims in document (21) relate to "the Mg-salt of the (-)-enantiomer of omeprazole". It is specified in paragraph [0007] of document (21) that this expression means that "said compound is essentially free of the Mg-salt of the (+)-enantiomer of omeprazole". The board therefore construes the claims of document (21) as tolerating some contamination by the (+)-enantiomer, although no precise figure can be put on the term "essentially free". In contrast, the claims of the patent in suit specify the optical purity to be at least 99.8% e.e., which means that the maximum amount of the (+)-enantiomer that may be present is 0.1%. Therefore, the board concludes that the feature introduced in the patent in suit acts to limit the subject-matter claimed with respect to that claimed in document (21).

Respondent 9 effectively acknowledged as much, but argued that said additional feature did not alter the subject-matter claimed in substance, or the reasoning with respect to inventive step given in decision T 401/04 under point 3.1.2 of the reasons, in particular with respect to the choice of closest prior art as document (1). However, the decision relied on by respondent 9 in this respect, namely, T 990/96 (OJ EPO 1998, 489), deals with the issue of novelty and not that of inventive step, and is therefore not considered to be of relevance in the present context.

Indeed, the issue of the significance of said additional feature in relation to the assessment of inventive step, and in particular the choice of closest prior art, was a matter of dispute between the parties, and cannot be assessed without detailed examination of the substance of the case.

Therefore, it is concluded that the issues of fact are not the same as those under consideration in decision T 401/04, and, for this reason alone, the principle of res judicata does not apply. Consequently, the present board considers it to be incumbent upon it to evaluate and decide on the present appeal based on the merits of the case.

5. Main request, Article 100(c) EPC

5.1 The patent in suit was filed as a divisional application of the parent application EP-A-0 652 872, which was published as the international application designated in the present procedure as document (23). It is noted that pages 1 to 26 of document (23) are identical to the corresponding pages of the present application as originally filed, apart from the fact that the claims in the former (page 22, line 1) are now labelled as being preferred embodiments in the latter (page 21, lines 28, 29). In the following and in point 6 below, reference is therefore only made to document (23).

5.2 The respondents have objected to the term "prophylaxis" employed in claim 11 (cf. above point I). The appellant conceded that the prophylaxis of the conditions defined in claims 3 to 8 referred to therein was not explicitly disclosed in document (23), but submitted that the skilled person would understand that the inhibition of gastric acid secretion would inevitably prevent the related diseases from occurring in the future. However, a clear distinction must be made between the intellectual content of a term and that which is specifically disclosed. Therefore, although the term "treatment", used in document (23) with respect to the conditions now claimed (cf. paragraph bridging pages 4 and 5), may be viewed as generally covering both prophylactic and curative treatments, a distinction is not made between the two possibilities. However, upon reading claim 11 of the main request, the skilled person is presented with the additional information that prophylaxis is specifically envisaged, which is not directly and unambiguously derivable from document (23).

Hence, owing to said amendment, the ground for opposition according to Article 100(c) EPC is found to prejudice the maintenance of the patent on the basis of the main request.

First auxiliary request

6. Amendments (Articles 100(c), 123(2),(3) EPC)

6.1 In auxiliary request 1 the term "or prophylaxis" has been deleted from claim 11. The objection raised under point 5.2 therefore no longer applies. No objections were raised to this amendment under Article 123 EPC, and the board sees no reason to differ.

6.2 It therefore remains to be decided whether a direct and unambiguous basis can be found in document (23) for that which is now claimed.

Under the heading "Field of the invention" it is stated that "the present invention is directed to new compounds with high optical purity, their use in medicine ..." (page 1, lines 5, 6, emphasis added). Claim 1 relates to optically pure salts of (+)- and (-)-omeprazole whereby Mg**(2+)is listed as one of six possible counter ions. In dependent claim 3, four salts are explicitly listed, namely, the sodium and magnesium salts of each enantiomer, and these are also specifically depicted as most preferred salts in the corresponding passage of the description, including the optically pure magnesium salt of (-)-omeprazole IIb (see page 3, lines 4 to 30).

It is further disclosed on page 4, lines 1 to 4, that:

"With the expression "optically pure Na**(+) salts of omeprazole" is meant the (+)-enantiomer of omeprazole Na-salt essentially free of the (-)-enantiomer of omeprazole Na-salt and the (-)-enantiomer essentially free of the (+)-enantiomer, respectively".

Therefore, by way of this example, a general definition of the expression "optically pure salt" can be derived as being a salt that is "essentially free" of the other enantiomer.

The paragraph on page 4 goes on to state the following (page 4, lines 4 to 12; emphasis added):

"Single enantiomers of omeprazole have hitherto only been obtained as syrups and not as crystalline products. By means of the novel specific method according to one aspect of the invention of preparing the single enantiomers of omeprazole, the salts defined by the present invention are easy to obtain. In addition, the salts, however not the neutral forms, are obtained as crystalline products. Because it is possible to purify optically impure salts of the enantiomers of omeprazole by crystallisation, they can be obtained in very high optical purity, namely >=99.8% enantiomeric excess (e.e.) even from an optically contaminated preparation".

This is the only passage of document (23) to provide a specific definition of optical purity, and it is directly and unambiguously derivable therefrom that the level obtainable for the salts defined by the invention by means of the disclosed purification process is >= 99.8% e.e. Therefore, the limitation of the expression "optically pure" to this level of enantiomeric excess for the salts specifically disclosed in document (23) does not contravene Article 123(2) EPC. The passages referred to above are thus considered to provide a proper basis for the magnesium salt according to claim 9 of auxiliary request 1.

The basis for the use of the claimed salt in therapy, as well as for a crystalline form and pharmaceutical composition thereof, as claimed in claims 10, 12 and 13 of auxiliary request 1, can be found in the following passages of document (23): page 1, lines 5, 6, and claim 18; page 4, lines 7 to 12; and page 7, lines 25 to 27, and claim 17.

The specific uses appearing in the present claims are disclosed in document (23) on page 4, line 23 to page 5, line 2; on page 5, line 7; and in claims 19 and 20. Therefore, claims 1 to 8 and 11 of auxiliary request 1 are also not open to objection.

6.3 The respondents' arguments are not considered to be persuasive for the following reasons:

As explained above under point 6.2, the optically pure magnesium salt of (-)-omeprazole is disclosed in individualised form in document (23), on page 3, lines 17 to 30 and in claim 3. Therefore, it cannot be accepted that a selection is already to be seen in the choice of the magnesium counter ion in combination with the (-)-enantiomer of omeprazole.

Moreover, the second passage from page 4 of document (23) reproduced above under point 6.2 states that "the salts defined by the present invention are easy to obtain". In the process that follows "optically impure salts of the enantiomers of omeprazole" are purified by crystallisation. Thus, this passage clearly describes a process that is generally applicable to all salts of the invention, and is not restricted to sodium salts. Moreover, the pronoun "they" in the clause "they can be obtained in very high optical purity, namely >=99.8% enantiomeric excess (e.e.)" refers back to the subject of the preceding clause, namely, said "optically impure salts". Thus, although the process described proceeds via a crystalline product, the defined level of purity is not forcibly linked to crystallinity, and this is to be seen as an optional feature. Confirmation is also provided by the following paragraph of document (23) (page 4, lines 19 to 21) wherein it is disclosed, with reference to said method, that "it can be used to obtain the single enantiomers of omeprazole in neutral from as well as the salts thereof", without any mention of crystallinity.

Concerning the specific medical uses listed in document (23), these are disclosed as belonging to a single class of condition, namely, which are treatable by the inhibition of gastric acid secretion. Moreover, the salts of (+)- and (-)-omeprazole are disclosed in document (23) as being equivalent in displaying this activity (see page 4, lines 23, 24 and claim 19), and therefore as being suitable for the use in the treatment of the conditions listed. Under these circumstances, it cannot be accepted that the claims of auxiliary request 1 referring to specific medical uses, such as claim 5, present the skilled person with any new information which was not directly and unambiguously derivable from document (23).

Regarding paragraph [0002] of the patent in suit, it is noted that no amendments have been undertaken with respect to the corresponding paragraph in document (23) on page 1, lines 12 to 22. It is disclosed therein that the present invention provides "compounds with improved pharmacokinetic and metabolic properties which will give an improved therapeutic profile such as a lower degree of interindividual variation", namely, "novel salts of single enantiomers of omeprazole". The point of reference for the alleged improvement can be found in the first sentence of the paragraph, namely, "omeprazole, and therapeutically acceptable alkaline salts thereof". The claims have now been limited to a specific salt of (-)-omeprazole. However, it cannot be inferred from document (23) that the information that this specific embodiment exhibits an advantage with respect to the racemic mixture necessarily implies that other embodiments, which are now no longer claimed, do not, as suggested by the respondents. Therefore, the limitation of the patent in suit to one of the preferred embodiments disclosed in document (23) is not considered to lead to the provision of any additional information extending beyond the content of the latter.

With respect to paragraph [0036] of the patent in suit, this corresponds to the paragraph on page 21, lines 6 to 20, of document (23). This example aims to demonstrate the stability towards racemisation at different pH values (see title). The first sentence of this example refers "the optically pure compounds of the invention" and the second to the (-)-isomer of omeprazole. The precise identity of the compound used in this experiment is not disclosed, and the same uncertainty applies to paragraph [0036] of the patent in suit. It cannot therefore be accepted that the information derivable from said example changes according to context.

6.4 Consequently, the subject-matter of auxiliary request 1 does not extend beyond the content of the application as filed, or of the content of the parent application as filed (Articles 100(c) and 123(2) EPC).

7. Entitlement to priority (Article 87 EPC)

The respondents did not advance any additional objections to those raised under Article 100(c) EPC.

Passages corresponding to the decisive passages of document (23) discussed under point 6.2 above are to be found in the present priority document (28), apart from page 5, line 7 of document (23), which is the line referring to the treatment of Helicobacter infections (cf. document (28), page 1, lines 5, 6; page 3, line 1 to page 4, line 7; page 4, lines 15 to 24; page 7, lines 10 to 12; claims 1, 3, and 15 to 18).

Auxiliary request 1 is therefore entitled to the priority date claimed, apart from claim 8, which relates to the treatment of Helicobacter infections, and claim 11 in so far as it refers to claim 8.

8. Sufficiency of disclosure (Article 100(b) EPC)

8.1 As outlined above under point I, the claims under consideration relate to a specific magnesium salt (claim 9) and a crystalline form thereof (claim 12), and pharmaceutical compositions and first and second medical uses thereof.

The patent in suit provides methods for the synthesis of compounds of claims 9 and 12 (see page 3, lines 2 to 6; paragraphs [0012] to [0017]; and example 1). Pharmaceutical formulations thereof are disclosed in paragraphs [0018] to [0025].

The board is therefore of the opinion that the requirements of sufficiency of disclosure are fulfilled, since the skilled person, having regard to the general guidance and examples provided in the patent in suit, would have been in a position to provide the claimed salts and employ them in therapy, and specifically in the treatment of medical conditions of the type claimed.

8.2 The respondents' arguments with respect to sufficiency of disclosure are not considered to be convincing for the following reasons:

The fact that a synthesis of the N-chloromethylated starting material used in example 2A is not provided in the patent in suit is not considered to be detrimental to sufficiency of disclosure. The skilled person in search of a synthesis of said compound would certainly have consulted the Chemical Abstracts database, as a standard source of chemical information in the field. Thus, following standard procedures for retrieving information from Chemical Abstracts, the skilled person would first establish the molecular formula of the compound of interest and check the collective formula index to see if there was a corresponding entry citing the chemical name and abstract number. Document (84) includes the relevant excerpts, available at the priority date of the patent in suit, from the print version of Chemical Abstracts. As can be seen from the last page of document (84), the standard procedure outlined above would have led the skilled person directly to the relevant abstract (i.e. molecular formula C18H20ClN3O3S; compound name lH-benzimidazole 1-(chloromethyl)-6-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-; abstract number 110: 57664p), and to the cross-reference to document (83), in which the desired synthesis is to be found (page 35). Thus, in the present case, the information sought was retrievable in a direct and straightforward manner, without necessitating a comprehensive search. Therefore, since the starting material of example 2A was readily available to the skilled person, the synthesis disclosed therein is considered to be sufficiently disclosed.

The present situation is not comparable with that underlying the decision T 206/83 (see OJ EPO 1987, 5). In that decision, it is apparent that the compounds in question were not traceable through the index of Chemical Abstracts (see point V.b), and it was held under the circumstances that "reliance on the contents of Chemical Abstracts to rectify insufficiency might be tantamount to leave the skilled reader to carry out a search in the whole state of the art, which would be an unacceptable burden on the public" (see point 6, emphasis added). It is further noted that in decision T 206/83, the board went on to analyse in detail why none of the required compounds were available to the skilled person through common general knowledge (points 7 to 11). This step has been omitted from the respondents' argumentation in the present case.

Lack of sufficiency was further alleged based on the method used for measuring enantiomeric excess was not disclosed in the patent in suit. However, no convincing case was made by the respondents as to why the available methods cited by the appellant for performing analytical chiral chromatography would not have yielded reliable results. It is further noted that this argument is inconsistent with the submission of the respondents that preparative HPLC columns had been commercially available at the present priority date that were suitable for separating the enantiomers of omeprazole. This objection is therefore to be rejected as being unsubstantiated in the absence of evidence to the contrary.

Finally, decision T 609/02 relates to a claim in which the effect in question is expressed as a functional feature thereof (see points VII and 9). In contrast, in the present case, the effect of reduced interindividual variation is part of the problem to be solved (see point 10.4 below). The principles established in decision T 609/02 are therefore not relevant for the present case.

8.3 Consequently, the requirement of sufficiency of disclosure is considered to be met by auxiliary request 1 and the objection under Article 100(b) EPC is to be rejected.

9. Novelty (Articles 52(1) and 54 EPC)

A novelty objection was raised with respect to document (1). The passage on page 6, lines 31 to 42 discloses six enantiomers, including (-)-omeprazole (line 38), and their salts with bases (line 42). However, no specific salt of the compounds listed is disclosed. The magnesium salt according to present claim 9 is therefore considered to be novel over this disclosure.

Magnesium is listed as a counter ion on page 3, line 54, but only in the context of the reaction of the unresolved starting material with the chiral auxiliary of formula II (see page 3, line 51 and page 2, lines 26 to 64).

Thus, the subject-matter of claim 9, and consequently that of the remaining claims of auxiliary request 1, are novel over document (1).

None of the remaining cited prior art documents disclose the salt of present claim 9.

Accordingly, the subject-matter of auxiliary request 1 meets the requirements of novelty.

10. Inventive step (Articles 52(1) and 56 EPC)

10.1 In accordance with the problem-solution approach applied by the boards of appeal to assess inventive step, it is first necessary to identify the closest prior art, then to determine in the light thereof the technical problem which the claimed invention addresses and successfully solves, and finally to examine whether or not the claimed solution to this problem is obvious for the skilled person in view of the state of the art.

In this context, the parties referred extensively to the "Case Law of the Boards of Appeal of the EPO", 6th edition 2010, chapter I, section D, points 2 and 3.

As explained therein under point 2, the problem-solution approach was primarily developed to ensure an objective assessment of inventive step.

As further outlined under points 3.1 to 3.4, the aim with regard to the choice of closest prior art is to identify a starting point which the skilled person would have realistically taken under the circumstances of the claimed invention. Therefore, the first consideration in this selection is whether a prior art document discloses subject-matter conceived for the same purpose or aiming at the same objective as the claimed invention. A further consideration is the structural similarity with the claimed invention, in terms of common relevant technical features. In cases of doubt as to the choice of closest prior art, the problem-solution approach should be repeated taking possible alternative starting points.

10.2 In the present case, it is explained in paragraph [0002] of the patent in suit, in the section entitled "Background of the invention", with reference to documents (36) and (2), that omeprazole and its alkaline salts are known to be effective gastric acid secretion inhibitors, and are useful as antiulcer agents. It is further disclosed that these compounds exist as two optical isomers (enantiomers). Paragraph [0002] then goes on to state that "it is desirable to obtain compounds with improved pharmacokinetic and metabolic properties which will give an improved therapeutic profile such as a lower degree of interindividual variation", and that "the present invention provides such compounds, which are novel salts of single enantiomers of omeprazole".

Thus, the patent in suit relates to the field of gastric acid secretion inhibitors and aims at providing compounds having an improved therapeutic profile.

The subject-matter of auxiliary request 1 in its broadest product claim 9 is directed to a magnesium salt of (-)-omeprazole with an optical purity of >= 99.8% e.e.

10.3 In the light of the foregoing, it must now be decided whether, as argued by the appellant, document (11) or (2) is to be seen as the closest prior art, or whether, as argued by the respondents, document (1) represents a more appropriate starting point.

10.3.1 Document (11) provides an overview over the class of gastric acid secretion inhibitors, otherwise known as proton pump inhibitors (PPIs), based on the following pyridylmethyl benzimidazole sulfoxide template, also known as timoprazole:

FORMULA/TABLE/GRAPHIC

Details are provided of their mode of action, and the effect on activity of various structural modifications to this template (pages 198 to 204). Under point 6.4.2.6.4 (page 204), it is stated that, "more than 40 companies have now patented in this area", but that "relatively few compounds had reached the clinic". The next section 6.4.2.6.5 focuses on omeprazole itself and states under the heading "clinical profile" that "omeprazole (Losec) is the first therapeutically proven proton pump blocker and is clearly emerging as a significant advance in the treatment of peptic ulcer and related diseases". This is followed on page 205 by a section dealing with "limitations of omeprazole should be considered by the medicinal chemist designing new proton pump blockers with advantages over omeprazole", whereby the main disadvantage of omeprazole is stated to be "its ready activation at mildly acidic pH", as a result of which the drug has to be administered as an enterically coated formulation to prevent its destruction in the stomach (see page 205, point (ii)(5)).

10.3.2 Document (2) takes omeprazole at its starting point (see page 1, lines 6 to 30) and provides new forms thereof which exhibit improved storage stability (page 2, lines 1 to 15), namely, specific alkaline salts (claim 1). The magnesium salt is particularly preferred, especially for the preparation of tablets (claim 4, and page 3, lines 7, 8). Pharmaceutical compositions and the uses thereof related to the inhibition of gastric acid secretion are disclosed on page 5, line 29 to page 8, line 8 and in claims 8 to 11. The magnesium salt is prepared in examples 5 and 6, and incorporated into an enteric-coated tablet in example 12.

10.3.3 Document (1) is entitled "Enantiomerentrennung" ("Separation of Enantiomers") and starts with a paragraph describing the field of the invention (page 2, lines 4 to 9), which is translated in document (1A) as follows (emphasis added by the board):

"The invention relates to a process for the resolution of chiral pyridylmethylsulphinyl-1H-benzimidazoles into their enantiomers. The enantiomers are used in the pharmaceutical industry for the production of medicaments."

In the introduction (page 2, lines 10 to 23), it is pointed out that, despite the large number of patent applications in the field of gastric acid secretion inhibitors based on the timoprazole template, no process had been described for separation thereof into their enantiomers, and consequently the latter have not as yet been isolated and characterised.

In the following description of the invention (page 2, line 24 to page 4, line 14), a process is disclosed for the resolution of timoprazole-based compounds of formula (I) into their optically pure enantiomers wherein the racemate is reacted with a chiral auxiliary of formula (II) to form a regio- and diasteromeric mixture of formula (III). The diastereomers are then separated, and converted into the optically pure compound by solvolysis in a strongly acidic medium, followed by a work-up procedure.

On page 4, lines 15 to 17, it is stated that the compounds of formula (III) and the optically pure compounds of formula (I) are novel and therefore a subject of the invention. There then follows a table listing specific exemplary combinations of substituents for these compounds obtainable according to the process of the invention (page 4, line 18 to page 6, line 30), whereby six enantiomers, and their salts with bases, are then listed as being particularly preferred (page 6, lines 31 to 42). The chemical names in this list correspond to (+)- and (-)-pantoprazole, (+)- and (-)-omeprazole, and (+)- and (-)-lansoprazole.

In the following examples, (+)- and (-)-pantoprazole, and (+)-omeprazole are prepared (page 6, line 43 to page 7, line 37).

The description ends with a section entitled "Gewerbliche Anwendbarkeit" ("Commercial Utility") (page 7, lines 39 to 49), which has been translated in document (1A) as follows:

"Pyridylmethylsulphinyl-1H-benzimidazoles can be resolved into their optical antipodes for the first time by the process according to the invention. The fact to be judged as particularly surprising here is that the liberation of the optically pure compounds from the diastereomers is carried out with the aid of highly concentrated mineral acids, although it is known that the pyridylmethylsulphinyl-1H-benzimidazoles are very acid-labile compounds.

The compounds prepared according to the invention are employed as active ingredients in medicaments for the treatment of gastric and intestinal disorders. Reference is made, for example, to European Patent 166 287 with respect to the manner of use and dosage of the active ingredients."

Finally, the claims of document (1) are directed to optically pure compounds of formula (I) (claims 1, 2), a process for their preparation (claims 3, 4), and intermediates of formula (III) (claims 5, 6).

10.3.4 Thus, as outlined above under points 10.3.1 and 10.3.2, both documents (11) and (2) relate to the active pharmaceutical ingredient omeprazole, the therapeutic properties of which had been extensively investigated and were well understood. Therefore, both documents represent realistic starting points for the skilled person in the field of pharmaceutical drug research and development, seeking improved drug candidates.

The board considers, however, that document (2) constitutes a closer prior art than document (11), since it is directed to a related objective to that specified in the patent in suit, namely, that of providing improved drug forms of omeprazole. Moreover, the magnesium salt disclosed in document (2) only differs from that claimed in the fact that the omeprazole molecule in the salt is racemic rather than a single enantiomer, and is therefore structurally closer to the subject-matter claimed than the free base disclosed in document (11).

10.3.5 In contrast, the board does not regard document (1) to be a realistic starting point for the assessment of inventive step.

As summarised above under point 10.3.3, the invention according to document (1) mainly relates to a process for the enantiomeric resolution of the class timoprazole-based PPIs of formula (I).

It is stated that the optically pure compounds obtained are a subject of the invention because they are novel (see page 4, lines 16, 17). Although it is implied that the isolation of these compounds would allow their characterisation (see page 2, lines 20 to 22), the properties that are of interest in this respect are not specified. Indeed, the only characterisation provided for the (+)-omeprazole obtained as an amorphous solid in example 6 is its optical rotation value.

Although the use "in the pharmaceutical industry for the production of medicaments" is mentioned (page 2, lines 7, 8), none of the claims relate to medical uses, and there is only one paragraph in document (1) referring to a concrete medical use of the compounds prepared according to the invention, namely, for the treatment of gastrointestinal disorders (page 7, lines 46 to 48). With regard to their manner of use and dosage, reference is made to the basic patent disclosing racemic pantoprazole (see document (37), in particular, page 12, line 47). This paragraph of document (1) can therefore only be said to provide a general statement of field of activity by reference to that of the unresolved starting materials of the process disclosed.

In summary, the overwhelming focus of document (1) is on providing a process for resolution, and it is in no way concerned with investigating any particular pharmaceutical properties of the resolved enantiomers, let alone with providing any improvement in this respect. Under these circumstances, the board concludes that this document cannot be regarded as a realistic starting point for a skilled person seeking improved drug candidates.

10.3.6 The further arguments of the respondents in favour of document (1) as closest prior art are not considered to be convincing for the following reasons:

It is firstly noted that, although document (1) is cited in the patent in suit (see paragraph [0003]), this is not in the context of identifying the starting point for solving the problem posed.

Moreover, it is not convincing that the problem as defined in the patent in suit is artificial. Thus, whilst omeprazole was clearly considered to be a very effective drug (see e.g. document (38), pages 46 to 48), this does not mean that there was no room for improvement (see document (11), section 6.4.2.6.5(ii), "Disadvantages"). Indeed, a number of documents cited confirm that omeprazole had not been found to be equally effective in all patients, also at doses of 20 or 40 mg (see document (104-D), page 903, left-hand column; document (105-6), page 486, "Introduction"; document (154), sentence bridging pages 965 and 966). It therefore cannot be seen as an unclear or artificial problem to attempt to generally improve on omeprazole's therapeutic profile, and specifically to reduce variability in response between patients. Therefore, this objective must be taken into account in assessing the closest prior art.

It is true that documents (1), (2) and (11) all relate to the same general technical field of gastric acid secretion inhibitors. Indeed, at the priority date, the basic mode of action of this class of pyridylmethyl benzimidazole sulfoxides was well understood (see e.g. document (11), sections 6.4.2.6.1 and 6.4.2.6.2). However, as explained under point 10.2 above, the problem that the patent in suit sought to solve was not simply to provide further compounds having this basic activity, but to provide PPIs having an improved therapeutic profile. Therefore, in order to ensure an objective assessment of inventive step, the board considers that it is not only necessary to determine the closest state of the art by reference to the general field of activity and the chemical structure of the compounds disclosed, but also to consider whether, taking into account the purpose of the claimed invention, a person skilled in the art would have had any reason to select a particular piece of prior art as a basis for further development. For the reasons set forth in point 10.3.5, the board has come to the conclusion that the skilled person would not have selected document (1) for this purpose.

On a structural level, the board agrees with the respondents that document (1) can be considered to be enabling, in the sense that the process described therein allows the disclosed enantiomers of omeprazole to be obtained. The patent in suit acknowledges as much, and the evidence submitted by the appellant cannot throw doubt on this fact, since the laboratory notebook pages attached to document (20) include an experiment in which an enantiomer of omeprazole was successfully synthesised by means of a method within the teaching of document (1) (see Exhibits J, K and L to document (20)). There was considerable dispute between the parties as to what levels of optical purity were achievable by means of the process of document (1) and as to what conventional methods of resolution were available at the priority date of the patent in suit. However, since these questions are not decisive for the present decision, they need not be discussed further.

Therefore, it can be accepted, as argued by the respondents, that the (-)-enantiomer of omeprazole disclosed in document (1) essentially differs from the subject-matter claimed in present claim 9 in that it is present as the free base. However, the magnesium salt of document (2) is structurally just as close since it also characterised by a single distinguishing feature, namely, in the fact that it is racemic. More importantly, a structural analysis cannot detract from the primary consideration, as outlined above under point 10.3.5, that the absence of an identifiable objective related to that derivable in the patent in suit disqualifies document (1) as a starting point for further modification. Under these circumstances, secondary considerations, such as the fact that document (2) is silent on the subject of enantiomers whereas document (1) discloses salts with bases, cannot be decisive in determining the choice of closest prior art.

Finally, concerning the feature defining "an optical purity of >= 99.8% enantiomeric excess", it was argued in the context of the discussion on res judicata that this would strengthen the selection of document (1) over document (2) as closest prior art. The board does not consider this argument to be persuasive, since the respective single structural features distinguishing the claimed subject-matter from documents (1) and (2), as outlined in the previous paragraph, remain the same, regardless of whether the degree of optical purity is specified or not. The board therefore agrees with the appellant that said additional feature defining a very high optical purity can be considered to reflect the intended objective set out in paragraph [0002] of the patent in suit, since the greater the degree of optical purity, the more marked will be any improvement in therapeutic profile. As explained above under points 10.3.4 and 10.3.5, it is the consideration of this objective that is decisive in the choice of document (2) as closest prior art.

10.3.7 The board also does not agree with the final line of argument of the respondents according to which inventive step would in any case have to be assessed starting from document (1) since it was to be regarded as a "feasible" starting point.

The board is aware of decisions T 21/08, T 967/97 and T 591/04 that were inter alia cited in this context, and in particular of the conclusion arrived at in decision T 967/97 (see point 3.2), which was cited in decision T 21/08 as follows (see point 1.2.3): "If the skilled person has a choice of several workable routes, i.e. routes starting from different documents, which might lead to the invention, the rationale of the problem-solution approach required that the invention be assessed relative to all these possible routes, before an inventive step could be acknowledged". The board in T 21/08 decided, after consideration of the facts of the case, that document E13 was considered to be a "feasible starting point" for the assessment of inventive step (see points 1.2.4 to 1.2.6). In decision T 591/04, three documents were regarded as "equally legitimate starting points" and "more or less equally promising" (see point 4.2). However, the rationale behind these decisions is not applicable to the present case, since, as explained in detail in above points 10.3.5 and 10.3.6, the present board does not regard document (1) to be a "realistic, feasible or legitimate" starting point for the assessment of inventive step in view of the problem posed in the patent in suit. In other words, in the opinion of the board, taking document (1) as a starting point for the analysis of inventive step relies on a hindsight knowledge of what is claimed and is therefore inappropriate for an objective assessment of inventive step.

The fact that the opposition division decided otherwise in the decision under appeal cannot change this conclusion. After all, it is a primary purpose of an appeal to give the losing party the possibility to challenge the appealed decision on its merits. Furthermore, as explained above under point 4, the principle of res judicata does not apply in the present case. The conclusions reached in decision T 401/04 are therefore not considered to be of consequence for the present decision.

10.3.8 Consequently, the board sees no reason to deviate from the starting point indicated in patent in suit for the assessment of inventive step. Document (2) is therefore considered to represent the closest state of the art.

10.4 The problem to be solved in the light of the closest prior art, as submitted by the appellant and derivable from the patent in suit, can be seen as lying in the provision of a PPI having an improved therapeutic profile, in particular with a lower degree of interindividual variation of therapeutic effect.

It is noted in this context that the problem to be solved has been formulated without reference to "improved pharmacokinetic and metabolic properties" (cf. paragraph [0002] of the patent in suit), since the inclusion thereof would result in inadmissible pointers to the solution (cf. "Case Law of the Boards of Appeal of the EPO", 6th edition 2010, chapter I, section D, point 4.3.1).

The solution as defined in claim 9 relates to a salt characterised by the fact that omeprazole is present as its (-)-enantiomer with an optical purity of >= 99.8% e.e.

10.5 As a next step, it has to be decided whether it has been rendered plausible that the problem defined under point 10.4 has been successfully solved with respect to the closest prior art.

10.5.1 In order to demonstrate that this was the case, the appellant has submitted a number of documents containing comparative data. The respondents contested that this post-published evidence should be taken into account, since there was no evidence in the patent in suit to render the alleged effect plausible, citing decision T 1329/04 in support of their case.

However, the facts of the present case differ substantially from those underlying decision T 1329/04.

Thus, in decision T 1329/04, the problem to be solved was defined as isolating a further member of the TGF-beta superfamily, and the solution proposed was a specific polynucleotide sequence encoding the polypeptide denoted as GDF-9 (Reasons, points 4 and 5). However, GDF-9 was not found to exhibit the most striking structural feature which would serve to establish it as belonging to the TGF-beta family, and lacked sufficient sequence homology with other family members (Reasons, points 7 and 8). In addition, no evidence had been provided in the application as filed that GDF-9 played a role similar to that of the transforming factor-beta (Reasons, point 9). In the face of these doubts, it was concluded that the application did not sufficiently identify said factor as a member of said family (Reasons, points 6 and 11). Under these circumstances, it was decided that post-published evidence could not be considered in order establish that a solution had indeed been provided to the problem posed (Reasons, point 12).

In contrast, in the present case, the structure of the claimed magnesium salt of (-)-omeprazole is fully consistent with that of the known class of gastric acid secretion inhibitors. This clearly differs from the situation in T 1329/04 where the structural features of the polypeptide were found to be inconsistent with that expected of the superfamily. Moreover, the patent in suit discloses a synthesis of the claimed salt (Example 1), and provides a clear statement that it provides "an improved therapeutic profile such as a lower degree of interindividual variation" (paragraph [0002]). When presented with this information, the board can see no reason a priori for the skilled person to regard it as being implausible, and no arguments were advanced to this effect. Therefore, this situation again differs from that dealt with in T 1329/04 where a concrete technical basis was given for the reservations expressed. It is noted in this context that the evaluation of information provided in the patent in suit for consistency cannot be equated with an assessment as to whether, without hindsight knowledge, the state of the art would render the claimed solution to the problem posed obvious.

In the patent in suit, a consistent and verifiable disclosure is provided of the essential elements of a specific structure and corresponding therapeutic benefit. Under these circumstances, the board considers it to be appropriate to take into account the post-published evidence submitted for the purpose of assessing whether or not the effect identified is indeed observed.

10.5.2 The appellant relied on a number of documents disclosing comparative studies in humans on administration of the same oral dose of (-)-omeprazole and omeprazole.

In a first category of experiments, the area under the plasma concentration-time curves (AUC) was examined as a measure of bioavailability. The results thereof may be summarised as follows:

- In Study A of document (80) (pages 6 to 9), the sodium salts of omeprazole and its optical isomers were administered in the form of oral solutions. The AUC values were measured on days 1 and 7 of daily treatment for two groups of healthy subjects, one of which was made up of extensive metabolisers (EMs) (dose 15 mg) and one of poor metabolisers (PMs) (dose 60 mg). In the EMs, the AUC of (-)-omeprazole at steady state (day 7) was approximately two-fold higher than for omeprazole. In the PMs, the pattern was reversed.

- The study discussed in document (147), section 2.1.2, appears to be based on the same data as that outlined in the previous paragraph (cf. e.g. number of patients, duration, dosage). It is additionally reported therein that, in the EMs, the increase in AUC from days 1 to 7 was more pronounced for esomeprazole ((-)-omeprazole) than for omeprazole (page 416, left-hand column). An explanation offered in document (147) for this observation is that the lower metabolic rate of esomeprazole than omeprazole is reinforced with repeated doses owing to the fact that one of the metabolites of esomeprazole, the sulfone, inhibits the major esomeprazole metabolising enzyme, CYP2C19 (see page 424, right-hand column, second complete paragraph).

- In document (105-3), the AUC values in healthy EMs at days 1 and 5 were compared for doses of 20 and 40 mg of omeprazole and its optical isomers, all administered as solutions of the sodium salts (cf. page 780, right-hand column, "Study drugs"). The results obtained were in line with those of document (147) (cf. page 784, left-hand column, first complete paragraph).

- In Study B of document (80) (pages 9 to 12), patients with gastroesophageal reflux disease were given enteric-coated pellets within gelatine capsules comprising the magnesium salt of (—)-omeprazole corresponding to 20 mg of neutral compound, or 20 mg of racemic omeprazole in the non-salt form. After five days of treatment, the AUC for the former was almost two-fold higher than for the latter, with less interindividual variation (see page 11, last paragraph, coefficient of variation for the mean AUC 59 vs. 88%, P < 0.000l).

- The AUC values reported in document (146) appear to correspond to those of Study B in document (80) (cf. e.g. Table 2 of document (80) with the first row of Table 3 of document (146)).

A second category of studies related to effectiveness in controlling gastric acid secretion. The results thereof may be summarised as follows:

- In Study B of document (80), additionally to the AUC data mentioned above, the effect on 24-hour intragastric acidity was measured on day 5. It was found that (-)-omeprazole, at a dose of 20 mg once daily, maintained an intragastric pH above 4 for 2.2 hours longer than omeprazole at the same dose (mean percentage of time 53 vs. 44%, P < 0.000l).

- Again, document (146) appears to report the same study in more detail (cf. e.g. Table 1 of document (80) with the second row of Table 2 of document (146)). It is additionally disclosed therein that the interpatient variability (as expressed by standard deviation) in the percentage of time for which intragastric acidity exceeded pH 4 was 19.7% for esomeprazole 20 mg and 22.8% for omeprazole 20 mg (see page 864, left-hand column).

- Document (101-12) reports a study in which patients with symptoms of gastroesophageal reflux disease (GERD) received esomeprazole or omeprazole in the form of 40 mg capsules once-daily for five days. The mean percentage of the 24-hr period with intragastric pH > 4 was found to be significantly greater (P < 0.001) with the former than with the latter on days 1 (48.6 vs. 40.6%) and 5 (68.4 vs. 62.0%), and interpatient variability significantly less (see page 956, right-hand column).

Thirdly, two documents were cited relating to randomised clinical trials comparing healing and symptom resolution in larger populations of GERD patients:

- In document (47), significantly more patients were healed at week 8 with esomeprazole 20 mg (89.9%, n = 656) vs. omeprazole 20 mg (86.9%, n = 650) (see Table 3 and Summary, P < 0.05). Moreover, a significantly higher percentage of heartburn-free nights were observed (see Table 4 and page 1253, right-hand column, last paragraph).

- In the study disclosed in document (101-16), the 20 mg esomeprazole group had a higher healing rate than 20 mg omeprazole group at 8 weeks (see Table 2: 90.6%, n = 587 vs. 88.3%, n = 588), but the difference was not significant (P = 0.621).

10.5.3 The first question that arose with respect to the comparative tests outlined under point 10.5.2 is whether they were properly designed to demonstrate that any effect observed had its origin in the distinguishing feature of the invention (see e.g. T 292/92, point 4.3.3).

The appellant conceded that none of the tests provide a direct comparison between the magnesium salt of (-)-omeprazole with that of the magnesium salt of the racemic mixture.

However, in all the studies listed, identical doses were used, based on the amount of neutral compound, and identical oral dosage forms, either as enteric-coated formulations or as a buffered solutions, in order to protect the drug from acid degradation in the stomach (see point 10.6.1 below and document (153), page 164, left-hand column, first complete paragraph).

It is further noted that, in Study A of document (80) and in document (105-3), alkaline salts (-)-omeprazole and omeprazole are compared, which accurately reflects the distinguishing feature of the invention over document (2). Moreover, it can be seen from Study B of document (80) that analogous trends in bioavailability were obtained when comparing the magnesium salt of (—)-omeprazole with racemic omeprazole. This lends credence to the appellant's argument that counter ion would not be expected to contribute to the effects under consideration, since the omeprazole molecule must be assumed to be in the free base form once it has been absorbed from the gastrointestinal tract.

The board therefore concludes that the test reports summarised under point 10.5.2 can be regarded as being pertinent since they reflect the impact of the distinguishing feature of the invention.

10.5.4 Turning now to said data, the board notes the following:

The first category of data relates to AUC values, which are known to correlate with inhibitory effect on gastric acid secretion (see point 10.6.1 below). The comparative studies demonstrate that in EMs, which make up the majority of the population (about 97% of Caucasians, see document (80), page 5), higher and less variable AUC values are observed for (-)-omeprazole than for omeprazole. In addition, with repeated doses, the increase is more pronounced for the former than for the latter. At the same time, the difference in AUC values with respect to PMs is reduced.

In the second set of data, (-)-omeprazole was shown to produce a greater duration than omperazole at an intragastric pH exceeding 4. This is the threshold used to differentiate between aggressive and nonaggressive reflux (see e.g. document (146), Introduction). Less interpatient variability was also observed.

Finally, document (47) reported that (-)-omeprazole was more effective than omeprazole in healing and symptom resolution in GERD patients with reflux oesophagitis. Although the study disclosed in document (101-16) did not confirm these results, it is reported therein that in a pooled analysis of both studies, superiority was confirmed (see paragraph bridging pages 855 and 856).

In view of the above results, the board is convinced that the weight of evidence confirms that the (-)-enantiomer of omeprazole provides an improved therapeutic profile and a lower degree of interindividual variation of therapeutic effect with respect to the racemate.

10.5.5 The additional arguments of the respondents challenging the pertinence of this data are not considered to be convincing:

The board firstly sees no reason to doubt the confirmation of the appellant in its statement of grounds of appeal (page 36, lines 34 to 36) that the (-)-omeprazole employed in the clinical trials in the references referred to in document (101) was always greater than 99.8% e.e. Indeed, it would clearly be in the interest of those conducting the studies to use material having the highest achievable optical purity, in order to maximise the likelihood of observing any effect. It is further noted that the US patent application with the serial number 08/376,512 referenced in document (80) (see pages 1 and 4) corresponds to patent number US-A-5 714 504, which is a family member of the present parent application.

Moreover, although it is true that statistical significance of the findings with respect to interpatient variability was not specified in document (146), other studies do provide this information (see above point 10.5.2 and document (80), page 11, last paragraph; document (101-12), page 956, right-hand column).

With respect to the Sierra study cited as reference [23] in document (168), it is stated in the first complete sentence on page 1454 that the authors were unable to assess methodological quality on the basis of the published abstract. Therefore, the information provided in Figures 3 and 4 of document (168) cannot be regarded as being sufficiently reliable to cast doubt on the conclusion reached in the previous section.

The respondents additionally cited documents (102) and (103) which are excerpts from the new drug application for Nexium (NDA 21-153) submitted to the US Food and Drug Administration (FDA). Document (102) comprises one sentence, which reads as follows:

"In addition, it is recommended not to allow the sponsor to claim that esomeprazole has any significant clinical advantage over omeprazole in the first-line treatment of these acid-related disorders because no data in support of such a claim have been submitted".

From this single sentence, the board cannot assess the context or criteria used by the reviewer in reaching its conclusion. Further information in this respect is to be found in the executive summary numbered as document (103). However, based on the level of detail provided therein, the board is not in a position to assess whether any of the additional data summarised therein would have altered the conclusion reached under above point 10.5.4.

Finally, the respondents objected to the fact that any advantage had only been demonstrated in human patients and that this was not reflected in the claims. However, under these circumstances, there is no basis under the terms of the EPC for requiring a compound claim to be limited to a particular purpose.

10.5.6 Having regard to the considerations outlined above, the board is therefore satisfied that the problem as defined under point 10.4 has been credibly solved by the salt defined in claim 9.

10.6 It remains to be investigated whether the proposed solution would have been obvious to the skilled person in the light of the prior art.

10.6.1 The skilled person starting from the magnesium salt of omeprazole as disclosed in document (2) would have been aware of the body of knowledge relating to the properties, pharmacology and pharmacokinetics of omeprazole and its analogues, as has for example been reviewed in documents (11), (38) and (154), which can be summarised as follows:

Omeprazole is essentially stable at neutral pH, but undergoes rapid decomposition at mildly acidic pH, and therefore needs to be formulated so as to protect it from destruction in the stomach (see document (11), page 205, point (ii)(5); document (38), section V.A; document (154), page 965, "Pharmacokinetics and Pharmacodynamics", first two sentences).

Once it is absorbed in the intestine, omeprazole undergoes extensive first-pass metabolism (document (38), section IX). Omeprazole interacts with the cytochrome P-450 system in the liver, and interactions with other drugs may thus occur (document (154), page 966, "Metabolism"; document (11), page 205, point (ii)(5)).

Its mode of action is summarised in document (154) as follows (page 965, right-hand column, first complete paragraph; see also document (38), section IV; document (11), sections 6.4.2.6.1 and 6.4.2.6.2):

"It ... reaches the parietal cells of the stomach through the bloodstream. At a pH of approximately 7 omeprazole is not charged and can cross cell membranes (Fig. 1). However, in the secretory canaliculus of actively secreting gastric parietal cells, where the drug is exposed to a pH of less than 2.0, omeprazole becomes protonated. It therefore ceases to be lipophilic and is trapped and concentrated. Omeprazole itself is inactive, but under acidic conditions it is converted to the active form, a sulfenamide**(11,12)that reacts covalently with the sulfhydryl groups of cysteine residues on the extracellular surface of the alpha subunit H**(+)/K**(+)—ATPase and inhibits the activity of the enzyme (Fig. 1)."

The conversion of omeprazole to the sulfenamide and its subsequent reaction with the enzyme are depicted in document (11) as follows (page 200):

FORMULA/TABLE/GRAPHIC

It is further explained in document (154) under the heading "Pharmacokinetics and Pharmacodynamics" (see also document (38), point VIII, in particular on page 41):

"Peak plasma concentrations occur two to four hours after oral administration**(15) and tend to increase during the first few days of treatment, probably because the increasing inhibition of gastric acid secretion results in less degradation of omeprazole in the gastric lumen. The plasma half-life of omeprazole is about 60 minutes,**(16) but because it is linked covalently to H**(+)/K**(+)—ATPase, the duration of action of a single dose exceeds 24 hours.**(17) The degree of inhibition of acid secretion thus does not correlate with the plasma concentration of the drug, but it does correlate with the area under the plasma concentration—time curve.**(18) A single 20-mg dose of omeprazole inhibits acid secretion by 65 percent after 4 to 6 hours and by 25 percent after 24 hours,**(18) but with subsequent doses inhibition increases, reaching a plateau after four doses.**(18) This increased activity is due both to increased bioavailability and to inhibition of more H**(+)/K**(+)—ATPase molecules."

Omeprazole is well tolerated and "has proved to be remarkably free of side effects" (see document (154), page 971, "Side Effects and Toxicity"; also document (38), sections X, XI.E).

10.6.2 Reviewing documents (11), (38) and (154), the board notes that, although the sulfoxides described were known to be optically active compounds, there is only a single reference therein to stereochemistry, namely, on page 204 of document (11) where the following is stated:

"There is no evidence supporting a stereochemical requirement for activity. This is not surprising in the light of the covalent nature of the drug-receptor interaction".

This appears to be a reference to the fact that the affinity for the site of action, i.e. pharmacodynamics, would not be expected to depend on stereochemistry since the sulfenamide active species is achiral.

The observation that a steady state is reached on repeated administration is suggested to be caused by less degradation of omeprazole in the stomach and long duration of action of omeprazole, owing to the covalent bonding of the sulfenamide species to the enzyme that it inhibits. In both these cases, chirality would not be expected to play a role.

Moreover, it is apparent from documents (11) and (38) that there was active research by a number companies in the area of PPIs, but that this was concentrated on structural modifications to the timoprazole template as a means for modifying pH stability and activity (see document (11), sections 6.4.2.6.3 and 6.4.2.6.4 research in document (38), sections V.B, V.C, VI and VII).

The issue of interindividual variation in the steady-state inhibition of acid secretion is addressed in document (154) (sentence bridging pages 965 and 966). However, the only solution proposed to this problem is an increase in dose (page 966, top; also document (11), page 205, last sentence of point (ii)(5)).

Consequently, no teaching can be found in the review documents (11), (38) and (154) pointing to the present solution to the problem posed.

10.6.3 The skilled person would have further been aware of the primary literature cited by the parties relating to omeprazole and its analogues, and enantiomers thereof.

Two documents were cited in this context that were published between the priority and filing date of the patent in suit, namely, documents (7) and (87). In view of the conclusion on the validity of the present priority for the relevant parts of auxiliary request 1 (cf. above point 7), these documents cannot be considered to belong to the state of the art as defined in Article 54(2) EPC. The same is true of documents (8) and (9) published after the present filing date. It is further noted that all these documents disclose very specific information and data relating to particular PPIs, and cannot therefore provide a legitimate basis for evidence of the common general knowledge or thinking of the skilled person at the priority date of the patent in suit. Consequently, documents (7) to (9) and (87) cannot be relied on in the assessment of inventive step.

The respondents further referred to a series of papers by T Andersson et al. numbered, in order of publication, as documents (153), (34) and (148). In document (153), it was observed that, following oral administration, two of the eight subjects examined showed significantly higher concentrations of omeprazole (page 169, left-hand column, first complete paragraph), and slower formation of hydroxyomeprazole (page 170, left-hand column, second complete paragraph). In the sentence bridging pages 170 and 171, it is suggested that "the hydroxylation of omeprazole and possibly some other metabolic reaction in the elimination of this drug is subjected to a genetic influence, as has been reported for several other drugs, e.g., debrisoquine, some beta-blockers, and mephenytoin". This suggestion is confirmed in documents (34) and (148), which disclose that a few Caucasian individuals (<5%) exhibit a slower metabolism of omeprazole, with significantly higher plasma levels than the average subjects, and that these subjects are also poor metabolisers of diazepam and S-mephenytoin (see documents (34) and (148), introductions). It is therefore hypothesised that

the metabolism of omeprazole and diazepam is associated with the S-mephenytoin hydroxylation polymorphism, and that the enzyme S-mephenytoin hydroxylase is either lacking or functionally altered in the poor hydroxylators (see document (34), left-hand column, last two sentences, and document (148), paragraph bridging pages 28 and 29).

Thus, these studies may be summarised as postulating that the enzyme S-mephenytoin hydroxylase is associated with the metabolism of omeprazole in Caucasians and that this enzyme is lacking or functionally altered in PMs. These documents are totally silent on the subject of the chirality of omeprazole, despite the fact that the enantioselectivity with respect to the metabolism of mephenytoin observed with this enzyme was well understood at the time, as can be deduced from the fact that the S/R enantiomeric ratio of mephenytoin is used to phenotype subjects as PMs and EMs in documents (34) and (148) (see document (34), left-hand column, second paragraph; document (148), paragraph bridging pages 26 and 27). Contrary to the contention of the respondents, the board can therefore see no basis for the respondents assertion that documents (153), (34) and (148) would lead to an expectation of significant enantioselective metabolism of omeprazole and thus provide an incentive to investigate the enantiomers thereof. Moreover, all three documents emphasise that the findings would be expected to have few clinical implications, in view inter alia of the fact that omeprazole had been found to be well tolerated and no dose-related side effects had been reported (see last paragraphs of each of these documents). Indeed, the existence of PMs implies that a small subpopulation of individuals would be given a dose that is higher than necessary. The skilled person would therefore have no reason to regard this issue to be of significance in addressing the issue of variability in therapeutic effect in the population as a whole.

Document (3) indicates in its introduction that successful resolutions of omeprazole have been achieved on an analytical scale by means of chromatography using human and bovine serum albumin, and discloses that this may indicate a difference in the degree of plasma protein binding of the two enantiomeric forms. However, no information whatsoever is provided as to whether any differences are actually observed and as to any expected clinical consequences thereof. Moreover, document (3) then goes on to disclose a chromatographic method for the separation of racemic omeprazole, yielding (+)- and (-)-omeprazole in quantities of 3 and 4 mg and enantiomeric purities of 82 and 95.6%, respectively (page 317). From in vitro tests with isolated gastric glands, the conclusion is reached that omeprazole was equal in potency to the (-)-enantiomer, and that the inhibitory effect of the racemate should be ascribed to the inhibitory action of both of its enantiomers (page 318). Based on this information, the skilled person would not expect to achieve any benefit from the use of a single enantiomer.

Furthermore, as outlined above under points 10.3.3 and 10.3.5, document (1) discloses a method of resolution of timoprazole-based PPIs, but does not provide any guidance as to the particular behaviour of the isolated enantiomers. Indeed, subsequent to the filing date of document (1), the inventors thereof authored document (164) describing the process leading up to the selection of pantoprazole as a clinical candidate. This paper details how structural modifications were undertaken in order to obtain inhibitors possessing a combination of high potency, similar to omeprazole and lansoprazole, but increased stability at neutral pH (cf. abstract and Table II); it is further disclosed that pantoprazole was selected for further evaluation over another candidate owing to its greater water solubility and low global lipophilicity, believed to be of benefit with respect to potential cytochrome P450 system interaction (see page 1054, left-hand column, first paragraph). Under the heading "Implications of the Mechanism of Action on Sulfoxide Stereochemistry", the achiral sulfenamide intermediate derived from pantoprazole (1a) is discussed with respect to its preparation, properties and reaction with thiols. It is further stated that, "due to their unique mechanism of action, therefore, the in vitro inhibitory activity of the enantiomers of 1a is anticipated to be identical as has been shown for omeprazole**(24) and Ro 185364.**(25)" Therefore, document (164) once again emphasises the energies directed towards structural modifications in the search for improved PPIs around the priority date of the patent in suit, and the expectation of equipotence of the enantiomers.

Finally, two documents were cited pertaining to lansoprazole. Document (174A) relates to studies into the metabolic fate in rats and dogs of racemic **(14)C-tagged material. One set of experiments reports differences in enantiomer concentrations following oral and intravenous doses thereof (see translation (174B), "Results and Discussion", point 2). However, no data is provided for the resolved enantiomers. In a subsequent publication, document (14), originating from the same company, Takeda Chemical Industries Ltd., the properties of the resolved enantiomers of lansoprazole were examined. In particular, acid formation in isolated canine parietal cells and H**(+)/K**(+)-ATPase activity in canine gastric microsomes were investigated, and similar conclusions were reached as in documents (3) and (164), as summarised in the last paragraph on page 1878 as follows:

"From these results it is suggested that both enantiomers of lansoprazole have antisecretory action due to the inhibition of (H**(+) + K**(+))-ATPase and that the inhibitory effects of the two enantiomers are almost the same, at least in isolated parietal cells. Differences in pharmacodynamics and pharmacokinetics of the enantiomers remain to be studied."

In summary, from the documents dealt with in this section, the board concludes that the consensus at the priority date of the patent in suit, derivable from documents (3), (14) and (164), and reviewed in document (11), was that the activity of omeprazole and its analogues was to be ascribed to both enantiomers, and that these had the same effect at the site of action, owing to their conversion to the achiral sulfenamide species. Although the possibility of pharmacokinetic differences is not excluded, the only one of the cited documents to actually mention the pharmacokinetics of the resolved enantiomers states that they "remain to be studied". Based on this statement alone, the skilled person would have had no expectation that an improvement in therapeutic profile would result from the use of the resolved enantiomers, and would therefore have no reason to explore this avenue.

10.6.4 Finally, the respondents attacked inventive step based on decision T 296/87 coupled with the general literature on the role of chirality in pharmacokinetics (documents (33), (149) to (152)), and corresponding recommendations of regulatory authorities (e.g. documents (12) and (42)).

In decision T 296/87, the following is stated in paragraph 8.4.1 under the heading "Inventive step" (emphasis added):

"Long before the contested patent's priority date, it was generally known to specialists that, in physiologically active substances (e.g. herbicides, fungicides, insecticides and growth regulators, but also pharmaceuticals and foodstuffs) with an asymmetrical carbon atom enabling them to occur in the form of a racemate or one of two enantiomers, one of the latter frequently has a quantitatively greater effect than the other or than the racemate. If - as here - the aim is therefore to develop agents with increased physiological activity from a physiologically active racemate the obvious first step - before any thought is given, say, to synthesising structurally modified products - is to produce the two enantiomers in isolation and test whether one or the other is more active than the racemate. Such tests are routine. Under established Board case law, an enhanced effect cannot be adduced as evidence of inventive step if it emerges from obvious tests."

As pointed out by the respondents, this passage does not make a distinction between pharmacokinetic and pharmacodynamic effects. This is not surprising since the board deciding case T 296/87 was not confronted with this issue. However, in the following paragraph 8.4.2, it was noted that the conclusion reproduced above could be generalised only to a limited extent, and several situations were listed where a different outcome could be envisaged, for example, "if the basic racemate were indeed known but not in line with the general technical trend".

Therefore, it must be decided whether the rationale underlying the above conclusion of decision T 296/87 applies equally to the present situation where no difference in pharmacodynamic effect of the enantiomers was to be expected (cf. above point 10.6.3). For this purpose, it is appropriate to examine the textbook knowledge and reviews numbered as documents (33) and (149) to (152).

In the most general of these citations, textbook excerpt cited as document (149), the following is listed as points to be considered with respect to the interaction of enantiomers in biological systems (emphasis in bold added by the board):

| | |

| "1. | Enantiomere besitzen in den meisten |

| | Fällen eine quantitativ unterschiedliche |

| | Wirkung, in manchen Fällen wirken sie |

| | qualitativ unterschiedlich, im Extremfall |

| | können die pharmacodynamischen Eigenschaften |

| | der Enantiomere sogar einander entgegengesetzt |

| | sein. |

| | |

| 2. | Enantiomere können sich in der Gewebeverteilung |

| | und in ihrer Eiweißbindung unterscheiden. |

| | |

| 3. | Enantiomere können Unterschiede in der |

| | Metabolisierungsgeschwindigkeit und im Metabolitenmuster |

| | aufweisen." |

| | |

This passage may be translated as follows (board's translation):

| "1. | In most cases, enantiomers exhibit quantitatively |

| | different activities, in some cases, their |

| | activities are qualitatively distinct, in extreme |

| | cases, the enantiomers may even have opposing |

| | pharmacodynamic properties. |

| | |

| 2. | Enantiomers may differ in their tissue distribution and |

| | protein binding. |

| | |

| 3. | Enantiomers may display differences in their rate of |

| | metabolism and metabolite pattern." |

| | |

The first statement under point 1, which relates to pharmacodynamic effects, closely reflects that in paragraph 8.4.1 of decision T 296/87. However, when it comes to pharmacokinetic properties (points 2 and 3), document (149) is much more cautious, and only refers to the possibility of differences therein, without commenting on any consequences thereof in terms of activity.

Documents (33) and (150) to (152) provide detailed accounts of the pharmacokinetic consequences of chirality in terms of absorption, distribution, metabolism, and excretion (ADME) effects. In document (33), it is explained that most drugs are absorbed across the intestinal epithelium entirely by passive mechanisms following oral drug ingestion, and that the importance of the lipophilicity of a drug far exceeds the effect of chiral interactions (see section II.A, page 64, first paragraph, and section II.B.1, pages 67, 68). The binding of enantiomers to plasma proteins can occur enantioselectively and may determine the relative concentrations of the enantiomers which are available for interaction with receptors or for metabolic modification (see paragraph bridging pages 64 and 65 and section II.B.2, pages 68 to 72). Finally, it is set out that "enantioselectivity may be displayed in the clearance of drugs, whether this is by direct renal excretion or secretion or whether by metabolism" (see section II.B.3, pages 72 to 81). Similar, analyses are presented in documents (150) to (152). Certain trends are emphasised in these documents, such as the fact that the most marked differences between enantiomers are to be found with regard to parameters that reflect interactions between drug molecules and metabolic enzymes (see document (150), page 48, right-hand column; document (151), page 552, first paragraph), or that intersubject variability in the ratio of plasma concentrations of enantiomers can result from differences in first-pass metabolism (document (152), page S10, left-hand column). However, all these documents also emphasise the multiplicity and complexity of the processes involved in the pharmacokinetics of chiral drugs. This is graphically illustrated in document (151) (Figure 1), in which a method is presented for classifying the various relevant pharmacokinetic parameters involved in the processes outlined above according to the level of organisation in the body, as a means for accounting for stereoselectivity in drug distribution and elimination (see Abstract).

Consequently, the board concludes that, in view of the background knowledge disclosed in documents (33) and (149) to (152) as summarised above, the skilled person would have appreciated that the enantiomers of omeprazole might differ in any one of the relevant pharmacokinetic parameters. However, in the absence of any relevant teaching in the available prior art relating to the field of PPIs (see above points 10.6.1 to 10.6.3), the skilled person would not have had any reasonable expectation that any such differences would translate into a therapeutic benefit on administering only one of the enantiomers of omeprazole. The present circumstances are therefore not comparable to those considered in decision T 296/87.

It is further noted in this context that there was considerable dispute between the parties as to whether the means of resolution of the enantiomers of omeprazole available at the priority date of the patent in suit (e.g. the process of document (1), or methods according to document (3) and related commercially available HPLC technology) would have allowed (-)-omeprazole to be obtained in sufficient quantity and quality in a routine manner. However, the board does not regard the answer to this question to be decisive. The fact remains that, in order to demonstrate the present therapeutic benefit relying solely on pharmacokinetic processes, clinical studies were required on a statistically relevant number of individuals (cf. point 10.5.2 above). In view of the considerable complexity and effort involved in such tests, the skilled person would not have embarked on such an avenue, in the absence of any reasonable expectation of success. In this respect, the situation also differs from that underlying decision T 296/87, where the tests required were considered to be routine.

Moreover, in contrast to the statement in paragraph 8.4.1 of decision T 296/87, where the "obvious first step" was considered to be to isolate and test the enantiomers, it is apparent that in the area of PPIs, as outlined under point 10.6.2 above, energies in the field were directed to "synthesising structurally modified products".

Finally, the documents cited by the respondents relating to regulatory considerations would also not provide the skilled person, starting from the racemic salt of document (2), with a motivation to resolve its enantiomers and investigate their pharmacokinetic properties. For example, in the last column of document (12), situations are described where the development of a single enantiomer should be considered. One example given is "where one enantiomer has a toxic or undesirable pharmacologic effect and the other does not", whereby it is cautioned that these "might reside not in the parent isomer, but in an isomer-specific metabolite". Another example is "when both enantiomers are pharmacologically active but differ significantly in potency, specificity, or maximum effect". However, neither of these situations apply in the present case. As outlined above under point 10.6.1, omeprazole and its metabolites were not thought to associated with any significant toxicological issues at the priority date of the patent in suit; in addition, differences in potency were not to be expected, since both enantiomers were known to rearrange to give the same active species. Moreover, in a general sense, it might theoretically be "good science and good sense" (cf. document (42)) to obtain as much information as possible on the individual enantiomers of a racemate. However, whether there was motivation to do so in any particular case must be based on the specific relevant circumstances. As outlined above, such a motivation could not be found in the present case.

10.7 In view of the above considerations, the board concludes that the subject-matter of claim 9 of auxiliary request 1 involves an inventive step. The same applies to the remaining claims, relating to second and first medical uses, a crystalline salt, and a pharmaceutical composition thereof.

11. Accordingly, the subject-matter of the claim set according to auxiliary request 1 meets the requirements of Articles 52(1) and 56 EPC.

Since this request is considered to be allowable, it is not necessary to comment on the lower-ranking auxiliary requests.

12. Request for referral of two questions to the Enlarged Board of Appeal (Article 112(1)(a) EPC)

In view of the conclusion reached by the board under point 10.7 above, respondents 1 to 4, 6, 7, and 9 to 13 requested the questions under point XI above to be put to the Enlarged Board of Appeal.

According to Article 112(1)(a) EPC, a board shall refer questions to the Enlarged Board of Appeal if it considers that a decision is required in order to ensure uniform application of the law, or if a point of law of fundamental importance arises.

In the present case, the questions formulated by the respondents start from the premise that there is more than one "feasible" starting point in the present case. However, as explained above under point 10.3.7, the board does not consider this to be an accurate assessment of the factual situation, and there is therefore no contradiction between the present case and the case law cited by the respondents. Consequently, there is no need to refer a question to the Enlarged Board of Appeal to ensure uniform application of the law. Moreover, the question as to whether there is one or more "feasible" starting points for the assessment of inventive step will depend on the facts of each individual case and is thus not a question of law.

Having regard to the above considerations, the respondents' request for two questions to be referred to the Enlarged Board of Appeal is rejected.

13. Auxiliary request to address inventive step starting from document (1) as closest prior art, and objection under Article 112a(2)(c) EPC and Rule 106 EPC

After request for referral to the Enlarged Board of Appeal had been rejected (cf. above point 12), respondents 1 to 4, 6, 7, and 9 to 13 requested, as an auxiliary request, to be given the opportunity to address inventive step of the subject-matter of auxiliary request 1 starting from document (1) as the closest prior art, reiterating their argument that, before an inventive step could be acknowledged, obviousness must be assessed relative to all feasible starting points, including document (1). However, as explained above under point 10.3.7, the board disagrees in substance with the respondents' assessment of document (1). Therefore, in accordance to the problem-solution approach, an analysis starting from this document is not considered to be relevant for deciding on the issue of inventive step. Therefore, this request was rejected.

Respondents 1 to 4, 6, 7, and 10 to 13 then raised an objection under Rule 106 EPC in conjunction with Article 112a(2)(c) EPC, alleging that their right to be heard had been violated, since they had been denied an adequate opportunity to present their full case on inventive step. However, in the board's judgment no violation of Article 113(1) EPC has occurred because all parties were given ample opportunity to fully discuss the issues relevant to the decision on inventive step, and in particular to present their case on the question of the suitability of the documents cited as closest prior art. The objection under Rule 106 EPC is therefore dismissed.

ORDER

For these reasons it is decided that:

1. The decision under appeal is set aside.

2. The case is remitted to the department of first instance with the order to maintain the patent with the following claims and a description to be adapted if necessary:

Claim(s): No. 1 to 13 of the auxiliary request 1 filed with the letter dated 6 April 2011 and received on 7 April 2011.

3. The request for referral to the Enlarged Board of Appeal of 15 November 2012 is rejected.

4. The objection of 16 November 2012 under Article 24(3) EPC is rejected as inadmissible.

5. The objection of 15 November 2012 under Rule 106 EPC is dismissed.

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