T 0278/14 - Comprising kills technical effect

Key points

• Claim 1 is for a method of preparing the medicine drospirenone using TEMPO (an organic compound) as catalyst rather than a Ru metal catalyst as in the prior art.
• The  [patentee] considered that the objective technical problem to be solved lay in the provision of a process for the production of drospirenone which did not require the use of heavy or toxic metals, such that there was no need for chromatographic purification at the end of the process.
• The Board: "Given that claim 1 does not exclude the use of heavy or toxic metals as suitable oxidants, co-oxidants or catalysts, and that the patent even cites a heavy metal salt within one of its preferred oxidising systems (see CuCl in paragraph [0017]), claim 1 encompasses processes that would require subsequent chromatographic purification. Hence, the technical problem as formulated by the respondent is not solved by claim 1 across its whole scope and needs to be reformulated in a less ambitious manner." 
• Therefore, the objective technical problem is providing an alternative preparation method. The claimed method is found to be an obvious alternative.

EPO T 0278/14 -  link

Claim 1 of the patent as granted (main request) reads as follows:

1. Process for the preparation of drospirenone, comprising the oxidation of 17alpha-(3-hydroxypropyl)-6beta,7beta,15beta,16beta-dimethylene-5beta-androstane-3beta,5,17beta-triol of formula (VIII) with a suitable oxidising agent in an organic solvent in the presence of a catalytic amount of the [TEMPO]  radical or a derivative thereof, said oxidation being followed by the addition of a protic acid directly into the same container in which the oxidation took place, to obtain the drospirenone of formula (I)

3.3 Objective technical problem

The respondent [patentee] considered that the objective technical problem to be solved lay in the provision of a process for the production of drospirenone which did not require the use of heavy or toxic metals, such that there was no need for chromatographic purification at the end of the process.

Given that claim 1 does not exclude the use of heavy or toxic metals as suitable oxidants, co-oxidants or catalysts, and that the patent even cites a heavy metal salt within one of its preferred oxidising systems (see CuCl in paragraph [0017]), claim 1 encompasses processes that would require subsequent chromatographic purification. Hence, the technical problem as formulated by the respondent is not solved by claim 1 across its whole scope and needs to be reformulated in a less ambitious manner.

Considering that there is no evidence on file that the process in claim 1 provides any advantage over the process of the closest prior art, the board concludes, in agreement with the opposition division and the appellant, that the problem to be solved is the provision of an alternative process for the preparation of drospirenone by oxidation/dehydration of the compound of formula (VIII) defined in claim 1.

3.5 Obviousness

Another of the respondent's arguments was that the need to combine three pieces of prior art, namely the invention of document (3), the teaching of document (1) and the previous knowledge depicted in document (3), in order to arrive at the claimed process confirmed the presence an inventive step.

This argument is not convincing either, because there is no general principle which determines that in order for a lack of inventive step to be established only two documents may be combined. Thus if, as in the present case, none of the modifications proposed in granted claim 1, whether independently or in combination, are linked to an unexpected effect, the fact that each modification was suggested in a different piece of prior art does not render the claimed subject-matter inventive. This is even more true of granted claim 1, where the non-isolation of the intermediate product was in the best case an option if not an unavoidable circumstance.

Lastly, the respondent argued that the appellant had indirectly recognised the inventiveness of the process in granted claim 1 because it stated in paragraph [0008] of document (14) that the successful oxidation of the steroids therein with TEMPO derivatives was surprising; this statement would apply mutatis mutandis to the process of granted claim 1.

In that respect, the board holds that the statement in paragraph [0008] of document (14) merely constitutes the appellant's personal opinion given in one of its patents. Such a statement can neither replace the assessment of inventive step before the board nor overturn the outcome of the problem-solution approach as applied above. Therefore, the respondent's argument based on document (14) has to be rejected.

3.6 For these reasons, the board concludes that the process in granted claim 1 is not inventive, and so Article 100(a) in combination with Article 56 EPC prejudices the maintenance of the patent as granted.

4. Admission of the auxiliary request - Article 13(1) RPBA

The auxiliary request was filed by the respondent in the course of the oral proceedings before the board, after the board had announced its opinion on the main request, i.e. at a very late stage of the appeal proceedings. The request contains a sole claim which is based on granted claim 1, with the specification that the protic acid is added at the end of the oxidation reaction.

According to the respondent, the request was a reaction to the unexpected situation arising during oral proceedings that the board considered the process of granted claim 1 not to be inventive.

This argument is not convincing because the reasons that led the board to the conclusion that the process of granted claim 1 was not inventive had already been raised by the appellant in its statement of grounds of appeal (see point 4.1.2). Hence, the board's conclusion cannot have taken the respondent by surprise.

The respondent further argued that a reaction to a particular situation that had arisen should be permissible because, if it was not, a large number of auxiliary requests would need to be filed at an earlier stage and the boards would be flooded with auxiliary requests.

The board cannot see that, in the circumstances of the present case, it would have been faced with an exceptionally high number of auxiliary requests if the respondent had wished to react earlier to the objections presented by the appellant in the written submissions filed at the appeal stage. Moreover, the respondent's approach disregards the fact that the parties to the proceedings have to present their case as completely as possible at the beginning of the appeal proceedings, as clearly indicated by the requirements laid down in Article 12 RPBA. This includes the presentation of foreseeable fall-back positions.

In addition, the board agrees with the appellant that the auxiliary request does not change the situation with regard to inventive step as to the main request, because the addition of the protic acid at the end of the oxidation reaction was already implicit in the discussion of the main request. So the amendment proposed in the auxiliary request prima facie does not overcome the outstanding objection of lack of inventive step and, at the same time, goes against the principle of procedural economy since its admission would have resulted in a repetition of the discussion on inventive step already held in relation to the main request.

Accordingly, the auxiliary request was not admitted into the proceedings (Article 13(1) RPBA).

5. In view of the outcome of the present decision in relation to the issue of inventive step, there was no need to decide on the ground of sufficiency of disclosure.

Order

For these reasons it is decided that:

1. The decision under appeal is set aside.

2. The patent is revoked.