T 1846/10 - Non-working examples and A83

T 1846/10

Publication date 03.07.2015 - [C] - for the decision, click here. 

Key point

• For insufficiency of disclosure, the burden of proof lies with the opponent, requiring serious doubts substantiated by verifiable facts. This does not mean that the opponent must file experimental evidence. If one of the examples shows that the invention does not work, this can be sufficient to discharge the opponent of the burden of proof and to shift it to the patentee.
• This should similarly apply to lack of technical effect for A56.
• In this case, the method step of attenuating the live vaccine was insufficiently disclosed. Restricting the claim in an auxiliary request to methods using the deposited attenuated live vaccine overcame this objection.  The claims of the auxiliary requests were also considered to involve an inventive step - in effect based precisely on the insufficiently disclosed attenuating step.

Reasons for the Decision

[...] 27. The board concludes from the above (see points 8 to 26), that example 5 of the patent represents evidence that the skilled person, by following the guidance of the patent, would fail to obtain an attenuated strain of L. intracellularis suitable for the preparation of a live vaccine.

28. The respondent submitted that for an objections of lack of sufficiency of disclosure to succeed there must be serious doubts, substantiated by verifiable facts, that the invention can in fact be carried out by the average person skilled in the art without undue experimentation or inventive skills (see decision T 19/90, reasons, point 3.3). Since the burden of proof lies with the appellant (the opponent), it was necessary to provide experimental evidence that the invention could not be carried. This had not been done.

29. In the board's judgement, verifiable facts are
(i) that example 5 of the patent was carried out in line with the general teaching of the patent,
(ii) that the percentage of animals which developed enteritis in example 5 was the same between the group vaccinated with the culture of a high passage strain of L. intracellularis and the non-vaccinated group, and
 (iii) that the histological lesions were worse in the vaccinated group (the evidence supporting this fact being in paragraph [0103] and the table on page 17 of the patent).

Therefore, the board concludes that example 5 of the patent provides verifiable facts which raise serious doubts that the invention can in fact be carried out by the average person skilled in the art without undue experimentation or inventive skills by following the guidance provided in the patent. Under these circumstances, no additional experimental evidence from the appellant is required as it can rely on the evidence provided by the patent itself. The board concludes that the appellant has discharged its burden of proof.

[...]

39. As regards the respondent's reliance on the deposited strain as evidence that the guidance provided by the patent was sufficient to carry out the invention, the board notes the following. The board accepts the respondent's argument that the deposited strain was likely to have been passed 40 times. Document D48 discloses that the culture of L. intracellularis in McCoys cells leads to 100% infectivity after 7 days. Because example 6 also uses McCoys cells for the culture of L. intracellularis, and cells are passed once 100% infectivity is reached, it is safe to assume that the deposited bacteria were passed once a week, which results in 40 passages in 40 weeks.

40. However, the board observes that the patent itself does not allow such a conclusion to be drawn (see points 9 to 13 and 31 to 32 above), and document D48 was not available to the public at the effective date of the patent. Thus, assuming that the deposited strain mentioned in paragraph [0125] of the patent was indeed passed 40 times, this means that it was not prepared according to the teaching of the patent (see point 17 above) and thus cannot be taken as evidence that the guidance provided by the patent suffices to put the claimed invention into practice over the whole scope claimed.

41. The respondent further submitted that once the skilled person had learned from the patent's teaching that L. intracellularis could indeed be attenuated by passaging and selection and that attenuated L. intracellularis was suitable as a live vaccine, this teaching could be reproduced by a skilled person by applying routine procedures according to the teaching of the patent. In this context the respondent relied on documents D50, D65, D66 and D68 as providing evidence that live attenuated vaccines of L. intracellularis had been produced after the effective date. It was also submitted that according to document D66 attenuation of L. intracellularis during repeated cell culture passage was a highly repeatable event happening on a consistent basis between the 20**(th)and 40**(th) passage of L. intracellularis in vitro.

42. The board has already concluded above that the patent teaches consistently that at least about 7 to about 12 passages should be carried out to obtain an attenuated L. intracellularis strain (see point 17). Thus, it does not help the respondent's case that, after the effective date of the patent, attenuated L. intracellularis strains were obtained by carrying out many more passages of the L. intracellularis bacteria in vitro. Even if the deposited strain had been passaged 40 times - that information is not derivable from the patent (see point 40 above). That attenuation is a repeatable event that occurs between the 20**(th)and 40**(th) passage of L. intracellularis in vitro is not disclosed in the patent either. Finally, the board considers that document D50 provides evidence that certain L. intracellularis strains required up to 80 passages to become attenuated (see page 30, line 6). Thus, it appears in any case questionable that obtaining attenuated L. intracellularis is a highly repeatable event happening on a consistent basis between the 20**(th) and 40**(th) passage of the bacteria in vitro.

43. In conclusion, the board, having regard to the facts and arguments presented to it, concludes that no evidence has been provided that by following the teaching of the contested patent the person skilled in the art would succeed in producing an attenuated L. intracellularis strain. On the contrary, example 5 constitutes evidence that he would fail and thus raises serious doubts that the invention can in fact be carried out by the average person skilled in the art without undue experimentation or inventive skills.

44. After realising that the instructions concerning passaging the L. intracellularis bacteria in the patent were insufficient to reliably obtain an attenuated L. intracellularis strain suitable as a live vaccine, the skilled person would recognize the need to perform further research. In the board's judgement, this additional research involves an undue burden in view of the technical context of the present case, which is characterized by the unpredictability of attenuation of L. intracellularis (see point 7 above) and the requirement of performing in vivo tests in suitable host animals (see point 12 above).

45. The respondent's final argument that claim 1 concerned the proliferation of an existing attenuated L. intracellularis strain and that according to the wording of the claim, "such strain is just there from the beginning", cannot succeed either. The first step of the method of claim 1 requires that attenuated L. intracellularis bacteria be cultivated. It is undisputed that no attenuated L. intracellularis bacteria were available to the public at the effective date of the patent (see point 7 above). It has also been established above (see points 8 to 43) that the guidance provided by the patent does not allow the skilled person to obtain an attenuated L. intracellularis strain without undue burden or inventive step. And in the board's view, an attenuated L. intracellularis strain certainly does not become available to the public by the mere exercise of drafting a claim which requires that attenuated L. intracellularis bacteria be cultivated. The steps recited in claim 1 can thus not be carried out by the skilled person without undue burden or inventive effort.

46. The board concludes from the above that the patent does not disclose the claimed invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. The main request fails to meet the requirements of Article 83 EPC.

Auxiliary requests I to V

Sufficiency of disclosure (Article 83 EPC)

47. In the board's judgement the above considerations under Article 83 EPC as regards claims 1 and 12 of the main request (see points 8 to 46) apply, mutatis mutandis, to claim 1 of Auxiliary requests I to V.

Auxiliary request VI

Admissibility, Article 84 and Article 83 EPC

48. Auxiliary request VI was filed during the oral proceedings before the board, after the board had announced its conclusion as regards sufficiency of disclosure of the main request and auxiliary requests I to V.

49. Claim 1 of auxiliary request VI is based on claim 1 of auxiliary request IV and relates to a method for producing a live vaccine against L. intracellularis which relies on the L. intracellularis strain deposited under ATCC 55783 as the starting material (see section VII above for the complete wording of the claim). The restriction of the attenuated L. intracellularis bacteria to the deposited strain represented an amendment to the respondent's case. Pursuant to Article 13 RPBA any amendment to a party's case after it has filed its grounds of appeal or reply may be admitted and considered at the board's discretion. The discretion is to be exercised in view of inter alia the complexity of the new subject-matter submitted, the current state of the proceedings and the need for procedural economy.

50. The appellant requested that the request be not admitted into the appeal proceedings. It was submitted that auxiliary request VI was filed at a late stage, that claim 1 had an unclear scope and that its subject-matter was insufficiently disclosed. Both these objections were based on the submission that the deposited strain might be genetically unstable. The appellant also stated that otherwise it had no objections against this request.

51. The board observes that lateness by itself is no reason not to admit the request into the appeal proceedings. The restriction of the attenuated L. intracellularis bacteria to the deposited strain which is indicated in the patent (see paragraph [0012]) to be the preferred attenuated L. intracellularis strain also cannot be considered surprising in the board's judgement. There is also no evidence on file that the L. intracellularis strain deposited as ATCC 55783 is genetically unstable. Therefore, the board was not persuaded by the appellant's objections under Articles 83 and 84 EPC.

52. The board considered that, although late filed, the amendment was not particularly complex and could reasonably be dealt with without adjourning the oral proceedings. In the exercise of its discretion under Article 13 RPBA the board thus decided to admit the auxiliary request VI in the appeal proceedings.

Articles 76(1), 123(2) and (3), and 54 EPC

53. The appellant had no objections under Articles 76(1), 123(2), 123(3) or 54 EPC and the board is satisfied that the requirements of these Articles are met by the subject-matter of auxiliary request VI.

Inventive step (Article 56 EPC)

54. Document D1 represents the closest prior art with respect to the invention. This document identifies L. intracellularis as the pathogen responsible for proliferative enteropathy in pigs and discloses its cultivation in vitro.

55. Starting from document D1, the problem to be solved by the patent can be formulated as the provision of a method for producing a vaccine against L. intracellularis, i.e. against porcine proliferative enteropathy.

56. The proposed solution consists in a method which rests on the cultivation of the L. intracellularis strain with the deposit number ATCC 55783. Pursuant to the patent, the deposited strain is the preferred attenuated strain N3434NP40wk (see paragraph [0012]). This strain is used as the master seed of a commercial vaccine and has been apathogenic, immunogenic and genetically stable for 10 years: see declaration D64.

57. Faced with the above problem, the person skilled in the art might have expected that repeated passaging of L. intracellularis was likely to reduce its virulence. However, as explained in point 7 above, it was not possible to predict what the result of passaging an L. intracellularis isolate might be. In fact, the skilled person knew that passaging of a bacterium does not necessarily, and certainly does not always, lead to an attenuated bacterium suitable as a live vaccine, i.e. being not only apathogenic, but also immunogenic and genetically stable.

58. In view of this, the person skilled in the art starting from document D1 would have had to do further research with no particular reason to expect success or guarantee that an attenuated L. intracellularis strain suitable for the production of a vaccine could indeed be produced. Under these circumstances, the finding of a specific attenuated L. intracellularis strain which is indeed suitable as a live vaccine, is to be considered surprising.

59. For these reasons the board concludes that the subject-matter of claim 1 involves an inventive step. The same applies to independent claim 11 of auxiliary request VI, which shares with claim 1 the inventive technical feature of the attenuated L. intracellularis strain with the deposit number ATCC 55783. Depended claims 2 to 10 are inventive by the same token. The requirements of Article 56 EPC are fulfilled.

Adaptation of the description

60. At the oral proceedings, the respondent filed amended pages 2 to 21 of the description to bring it into line with auxiliary request VI. No objections were raised by the appellant and the board is also satisfied that the amended description meets the requirements of the EPC.

61. With its letter dated 20 March 2015 the respondent filed a typed version of amended pages 2 to 6 of the description. This version has not been checked by the board as it was submitted after the board took its decision, which is based on the amended pages of the description submitted during the oral proceedings.

Order

For these reasons it is decided that:

1. The decision under appeal is set aside.

2. The case is remitted to the opposition division with the order to grant a patent on the following basis:

(1) Claims 1 to 11 according to auxiliary request VI filed during the oral proceedings on 12 March 2015;

(2) The amended description pages numbered 2 to 21 as filed at approximately 19:45 h during the oral proceedings of 12 March 2015.