Friday 8 December 2023

Does the EPO care about double patenting?

Although it has been a contentious issue in the past, the Enlarged Board of Appeal decision of G 4/19 clearly established that double patenting is not allowed. As the Guidelines for Examination G-IV 5.4 concisely puts it, "two patents cannot be granted to the same applicant with claims directed to the same subject-matter". G 4/19 provides a fuller definition of what is not allowed:

1. A European patent application can be refused under Articles 97(2) and 125 EPC if it claims the same subject-matter as a European patent which has been granted to the same applicant and does not form part of the state of the art pursuant to Article 54(2) and (3) EPC. 
2. The application can be refused on that legal basis, irrespective of whether it 
a) was filed on the same date as, or 
b) is an earlier application or a divisional application (Article 76(1) EPC) in respect of, or 
c) claims the same priority (Article 88 EPC) as the European patent application leading to the European patent already granted.

Given this clear guidance, one might expect that an examiner will raise an objection if, for example, an applicant files a divisional application with the same claim 1 that has already been granted on the parent application. This would be the clearest case possible of what is not allowed according to G 4/19, and something EPO examiners should be well aware of. As I have discovered recently, however, this does not appear to be the case. I have now found three examples of an applicant filing a divisional application with the exact same claim 1 that has already been granted on the immediate parent application, following which the search opinion has found no objections. These are: EP4092953, EP4184856 and EP4209954. Before you ask, the applications have different examiners but the same applicant. The first of these I have already written about here as it related to the question of when third party observations could have an effect. It turns out that double patenting, once it is pointed out, is in fact a serious enough objection that it can cause examination to be reopened after a communication under Rule 71(3) EPC has issued. This made me wonder whether examiners even check for this when preparing their search opinion for a divisional application. In all of the above three cases, it appears that the examiner did not because the search opinion in each of them simply stated:

This would, of course, be the case if the examiner was only looking for the usual things like novelty, inventive step, clarity and sufficiency because the same examiner had already examined the same claim for the parent application and found it allowable. 
Can anyone explain to me how a competent EPO examiner can examine the claims of a divisional application and entirely ignore the possibility of double patenting? In a related question, can anyone explain to me why an applicant would want to file a divisional with claim 1 in the exact same form as their recently granted parent application?


  1. I usually include the parent claims as filed, as an additional group of claims at the end, after the claims I'd like to have examined. The aim is, obviously, to avoid surrendering any disclosure that was in the test as filed.

    But no, just filing the same set again is a bit pointless, and risks inviting a Rule 137(5) objection. I've seen that happen in a divisional filed by another agent, and the only solution was yet another divisional with the associated payment of many renewal fees...

    1. So do I. It's a perfectly good safety net to include the parent claims as statements in the description on filing a divisional. I don't however see how it can possibly make sense to file claim 1 of the parent application as granted with the intention of broadening it out afterwards, which seems to be what is happening on two of these applications. If a broader claim 1 is what you are looking for, which might be justified in some cases, then that's what should be included when filing the divisional. A response to the applicant's broadening amendments has not yet issued on the second and third applications, but I would expect objections under Rule 137(5) and Article 123(2) / 76 to be raised. An anonymous third party has kindly pointed this out to the examiner though, just in case.

  2. Proof of the pudding12 December 2023 at 12:44

    I suspect that this has a lot to do with the time pressure under which EPO examiners operate.

    I have seen cases where an added matter objection is raised, only to be rescinded when the examiner's attention is drawn to the verbatim basis for the amendment found in the passage(s) previously cited by the representative. This suggests to me that, despite being told precisely where to look, some examiners do not (feel able to) spend the time that it takes to find what they are looking for.

    If time pressure really is the cause here, this would suggest that double patenting objections are more likely to arise when related cases have the same examiner. That would certainly accord with my experience.

    1. Without wishing to be unfair, I don't think that is a plausible excuse. It took me 5 minutes to see that claim 1 was the same as the granted parent, so I don't see why an EPO examiner couldn't also do this, especially so if they were the same examiner (as is often the case) on the parent and divisional. They managed to find time in each case to carry out the search and determine that the search fee should be refunded, so must have been aware that the claims related to the same invention. I think it's a matter of double patenting not being on their radar until it's specifically pointed out.

    2. Proof of the pudding12 December 2023 at 18:01

      With regard to what is behind double patenting objections being missed by the EPO, I don't think that it helps to ask whether a possible explanation is reasonable (or plausible). This is because an explanation can still be true even if, by any measure, there is no reasonable excuse for that being so.

  3. It is indeed not relevant whether an explanation is plausible but an excuse may or not not plausible.