Defending a patent in an EPO opposition against multiple inventive step attacks can put one in mind of Groucho Marx’s statement “Those are my principles, and if you don’t like them… well, I have others.” Opponents will frequently be permitted to mount a succession of attacks, starting from different documents, and claiming in each case that the starting document is the “closest prior art”, even if it is radically different from a previously argued starting document.
A recent change in the EPO Guidelines suggests that opponents will be constrained in the number of attacks which they can mount using different starting documents.
Opposition divisions have traditionally been reluctant to decide in advance which document is the closest prior art, and even less inclined to force an opponent to stick to that starting point. The opposition division will usually prefer to consider all attacks put forward (within reason) on the basis that the public interest requires them to be satisfied that the claims are non-obvious in the face of any plausible attack.
To be fair to the opposition divisions, the EPO Guidelines have traditionally supported this approach. Until a recent (November 1, 2018) revision, the instruction in the Guidelines stated:
In some cases there are several equally valid starting points for the assessment of inventive step… If a patent is to be granted, it may be necessary to apply the problem-and-solution approach to each of these starting points in turn… In such a situation, there is no need to discuss which document is “closest” to the invention; the only relevant question is whether the document used is a feasible starting point for assessing inventive step…”.
This passage gave opponents considerable latitude to present a multiplicity of attacks from different starting documents.
The new text of the Guidelines
The passage above has now been amended however, and since November 1 it now reads:
In some cases there are several equally valid starting points for the assessment of inventive step… If a patent is to be granted, it may be necessary to apply the problem-solution approach to each of these starting points in turn…
However, applying the problem-solution approach from different starting points, e.g. from different prior-art documents, is only required if it has been convincingly shown that these documents are equally valid springboards. In particular in opposition proceedings the structure of the problem-solution approach is not that of a forum where the opponent can freely develop as many inventive step attacks as he wishes in the hope that one of said attacks has the chance of succeeding (T 320/15, Reasons 1.1.2).
In the event of refusal or revocation, it is sufficient to show, on the basis of one relevant piece of prior art that the claimed subject-matter lacks an inventive step: there is no need to discuss which document is “closest” to the invention; the only relevant question is whether the document used is a feasible starting point for assessing inventive step…[see EPO Guidelines G-VII, 5.1]
The new Guidelines do not prevent an opponent from using several starting points, and applying the problem-solution approach to each. However, before being allowed to do so, the opponent should now expect to have to “convincingly show” that any other document is an “equally valid springboard” before being allowed to develop the inventive step argument for that document; patentees should find that oppositions divisions are more receptive to arguments that the opponent should be limited to one or a small number of “best” attacks and even then, to justify more than one starting point.
The case law
The reason for the change can be found in Decision T320/15, in which the Board of Appeal was considering if the opponent’s right to be heard was infringed because only one inventive step attack was considered and the opponent was not permitted to develop several lines of attack. The Board held (translated from French):
1.1.2 Concerning the second objection, the Board notes that according to the problem-solution approach, the appellant [opponent] should select, in a first step, the most promising document to arrive at the claimed invention. The appellant [opponent] complains that the Opposition Division did not allow him to make several selections of the closest prior art document and to support several attacks from each of those documents. However, there is no indication in the record that the appellant [opponent] did not have the opportunity to choose a document other than D4 as the closest prior art. Moreover, the structure of the problem-solution approach does not amount to a forum in which the applicant can at will develop various attacks starting from various documents of the state of the art in the hope that one of them would have a chance to succeed. Therefore the second objection must also be rejected.
The Board seems to have said: you were free to pick any starting point and develop your arguments; it was up to you to pick the best starting point and the EPO is not obliged to give you several bites at the cherry.
Opponents will need to take greater care in framing their primary inventive step attack, making sure that they can justify their choice of the closest prior art, and indeed to be satisfied themselves that they are putting their most promising document forward first when making the argument. If, as an opponent, you think you may have to mount several attacks from different starting points, you will need to be ready with convincing arguments as to why each starting point is equally valid, and as additional attacks may not be considered it is important to lead with the best attack first.
Patentees can increase their chances of success by spending time in developing strong arguments on the criteria for selecting the “closest prior art”, and developing reasons why alternative starting points are not equally valid. During oral proceedings, a patentee should be ready to argue against alternative attacks once the primary attack has failed.