Poison and antidote

Poisonous or toxic divisionals have been a somewhat exotic but much commented upon topic, that has led to the revocation of a handful of patents in the past few years.

The excitement and dread generated in the European patent profession will culminate when the Enlarged Board of Appeal of the EPO, to which the topic has recently been referred, issues its decision G 1/15, probably within the next couple of years.

It looks like most, if not all, of the profession hopes that the Enlarged Board will put an end to a theory which is often viewed as nonsensical. I am not sure that I concur with this unanimity. But what everyone will agree on is that there is no predicting with absolute certainty what the Board will have to say on this subject.

So, since the world will not stop turning and patent applications will not stop being filed while we are all waiting for the verdict of the wise people in Munich, it may be worth looking for an antidote to the poison.

To put it more simply, today’s question is whether there is a way to immunize newly filed patent applications against a possible “poisonous divisional” objection further down the road, in case the Enlarged Board does not dispel this objection as being rubbish.

In order to answer this question, we need to look more closely at what the problem really is about. This is where the notion of “partial priority” comes into play.

Let’s assume a first application A, and a subsequent European application B claiming the priority of A. Let’s also assume that the invention claimed in B is broader than what was originally disclosed in A. For example A discloses a process with a temperature in the range of 10-100°C, whereas a broader range of 5-500°C is claimed in B. Or A discloses an apparatus comprising one part soldered to another part, whereas B claims the same apparatus wherein the two parts are attached to each other by any possible means.

In such scenarios, quite clearly, the B claims do not fully benefit from the priority of A, since B does not relate to the same “subject-matter” as A (in accordance with opinion G 2/98).  The tricky issue is whether the priority claim is fully invalid or whether it is only partially invalid.

If the priority is held fully invalid, and if A is a European patent application which gets to be published (in principle after the filing date of B), then A becomes prior art under art.54(3) EPC, i.e. prior art for the purposes of the assessment of novelty only (not inventive step). Therefore, if A discloses one or more embodiments falling within the scope of the B claims, these claims are invalid. We could call this a “toxic priority” situation.

Moreover, even if A itself is not prior art, for instance because it never gets published, or because it is not a European patent application, the existence of a divisional application C stemming from B can also be prejudicial to the novelty of B. Indeed, the part of C which does benefit from the priority of A can be opposed to B for the purposes of novelty only. In such as case, the divisional application is said to be toxic to the parent. But the reverse is also true, and the parent B could be toxic to its child C.

One solution which has been proposed to get out of this mess is the notion of partial priority.

If we accept that the claimed subject-matter in B can be divided up into two parts, a first part that benefits from the priority of A and a second part that does not benefit from the priority of A, then an argument can be made that:

  • said first part is immune to any toxicity because it benefits from the earliest filing date in the family; and
  • said second part is also immune, because it is not disclosed in A, so that there can be no anticipation by A (or any other application in the family validly claiming the priority of A).
Can a poison container safely be generalized to a beverage container without losing the priority for the poison embodiment?
Can a poison container safely be generalized to a beverage container without losing the priority for the poison embodiment?

Whether and to which extent partial priority can be conjured up is one of the main questions that the Enlarged Board of Appeal has to deal with in G 1/15 (see the referral decision T 557/13). In the founding opinion on priority G 2/98 it was mentioned that “the use of a generic term or formula in a claim for which multiple priorities are claimed […] is perfectly acceptable […] provided that it gives rise to the claiming of a limited number of clearly defined alternative subject-matters”. There has been a debate as to what this exactly means, and whether this implies restrictions on the conditions under which partial priority in a generic claim can be acknowledged.

With all this in mind, and without being able to guess at the further guidance which the Enlarged Board will offer, it is reasonable to state that there is a risk of invalidation when a European application is filed:

  • which claims a priority,
  • which comprises claims that have been generalized relative to the teaching of the priority document,
  • if the priority document is a European patent application which gets to be published, or if one or more divisional applications are filed at any point of time.

But, oddly enough, there are instances in which more poison could lead to a cure.

In fact, one solution when the above risk is identified at the time of drafting a priority-claiming application consists in adding a fallback position containing a feature which is not disclosed at all in the priority document. Indeed, if the priority claim becomes invalid because of an added feature (as opposed to just because of a generalization), then there can be no anticipation by the priority document or by any parent or divisional application – since the added feature restores novelty over those. Ideally, the added feature should be minimal and not significantly affect the scope of protection. Remember: it is only necessary to restore novelty over a potential art.54(3) EPC disclosure, so inventive step is not at stake.

If we go back to the above examples, if A discloses a process with a temperature in the range of 10-100°C, and if this range needs to be broadened to 5-500°C in B, why not also add in B another innocuous feature not at all disclosed in A, at least in a dependent claim? For instance, we could add that the process is performed within a time frame of 1 minute to 100 hours, if this is relevant.

Or, if A discloses an apparatus comprising one part soldered to another part, and if the claims in B need to be broadened to all possible modes of attachment between the parts, why not also add in a dependent claim in B reciting that the apparatus weighs from 100 g to 100 kg, assuming this is a relevant range.

Thus, even if partial priority is denied for the generalized claim, it is always possible to rely on the fallback and decide to completely forget about priority and at the same time make sure that there can be no anticipation by A or any application claiming the priority of A.

This suggestion comes with two caveats, though.

The first caveat is that, in case any other relevant disclosure took place during the priority year, the complete loss of the priority date may not be an option. In that case, the only solution seems to go back to what was originally disclosed in the priority document A and stick to that.

The second caveat is that features to be added in the second filing B should be as innocuous as possible (in order not to significant restrict the scope of protection); but not completely meaningless. Indeed, meaningless limitations would not be enough to distinguish over an art.54(3) disclosure, bearing in mind that the disclosure has to be read and assessed by the skilled person. For instance, if A discloses an invention on a car, and if we decide to add in B that the car has four wheels, it is very possible that the skilled person will be deemed to understand the car of A as necessarily comprising four wheels, in which case we would be back to square one.


CASE REFERENCE: Board of Appeal 3.3.06, T 557/13, Infineum USA LP v. Clariant Produkte (Deutschland) GmbH, July 17, 2015

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