Self-collision of European patent filings: an accident waiting to happen?

It is a common legal premise around the world, including in the important territories of the USA and Japan, for an applicant’s own earlier filed but later published patent filings (an earlier filed co-pending application) to be unavailable for the assessment of patentability of subject matter that is claimed in a later patent filing for the same applicant and which has a filing date before publication of the earlier filing (a later filed co-pending application).

This is not the case in Europe. Article 54(3) of the European Patent Convention (EPC) allows any earlier filed co-pending application to be available for the assessment of novelty (but not obviousness) of a later filed co-pending application, irrespective of whether the applicant and/or inventor are common to both patent applications.

In light of this approach by the European Patent Office (EPO), effective drafting and filing strategies are devised on a daily basis in order to reduce the impact of an applicant’s own earlier patent filings on its subsequent patent filings. These often complex strategies are of particular importance in life sciences, where many follow-on patent applications are filed relating to only minor modifications of a particular technology, and often only a few months after the initial patent application for that technology was filed.

Over recent years there has been discussion amongst the European patent profession of whether Article 54(3) EPC is so unspecific as to hypothetically allow an application from the same patent family (eg, a priority application or a divisional application) to be citable against another application in that family (a concept known as self-collision).

Despite these hypothetical discussions, co-pending applications had not been seriously contemplated to include related applications from the same patent family, and so filing strategies to date have only taken into account patent filings from other patent families. Now, the seemingly farfetched concept of self-colliding priority and divisional applications has become reality.

Self-colliding priority applications

The UK High Court decision in Nestec SA & Ors v Dualit Ltd & Ors [2013] EWHC 923 (Pat) concerned both the alleged infringement and the question of validity of the UK portion of European patent EP (UK) 2 103 236. EP 2 103 236 claimed priority from a European application which was published as EP 1 495 702. Of key interest in this case is that the judgment concluded the patent was not entitled to priority and as such, certain claims lacked novelty over the priority application itself.

The lack of priority was found due to the broadening of some claim features between the content of the priority application and the application as filed, such that the claims of the patent covered both subject matter disclosed in the priority application and additional possibilities that had not been. In light of the priority claim being held invalid, the earliest effective date for the assessment of prior art became the filing date of the patent (rather than the priority date).

“Many follow-on patent applications are filed relating to only minor modifications of a particular technology, and often only a few months after the initial application.”

In this particular case, the priority application had continued to publication, and so due to the priority application now having an earlier filing date than the patent (ie, the original, but now invalid, priority date for the patent), EP 1 495 702 was considered to be an earlier filed co-pending application and therefore available for the assessment of novelty of EP 2 103 236 under Section 2(3) of the UK Patents Act 1977 (corresponding to Article 54[3] EPC).

In light of the priority application disclosing fundamentally the same invention as the patent but in a narrower form, its disclosure was held to anticipate a number of the granted claims of EP 2 103 236. No amendment was possible in order to remove the additional subject matter and as such it was not possible to overcome the self-collision of the patent with its own priority application.

In an unrelated case heard by the EPO boards of appeal (T680/08), the same situation as seen in the Nestec case was identified. However, in T680/08, revocation of the patent was avoided due to the patent proprietor being able to narrow the scope of the affected claims to remove the additional subject matter, thereby overcoming the selfcolliding priority application.

The UK court judgment in Nestec v Dualit and the willingness of the EPO boards of appeal to consider the self-collision of a patent filing with its own priority application clearly demonstrates that any European application claiming priority from an earlier European application could lack novelty if amendment resulted in a loss of priority.

Self-colliding divisional applications

In a related, and potentially more dangerous, development the EPO boards of appeal have now found (in T1496/11) that a divisional application may be available for the assessment of novelty under Article 54(3) EPC for its own parent application.

In T1496/11, it was held that claim 1 of patent EP 0 930 979 had been generalised to encompass more possiblities than were disclosed in the priority application. Accordingly, EP 0 930 979 was held not to possess a valid claim to priority.

As a result of this loss of priority, a divisional application that had been divided from EP 0 930 979 became available for the assessment of novelty of EP 0 930 979 under Article 54(3). The generalised claim 1 of EP 0 930 979 was therefore found to lack novelty over the narrower but wholly encompassed disclosure of the divisional application.

In this particular case, novelty was restored by amending claim 1 to a narrower scope that possessed a valid claim to priority. However, the decision has set a precedent for EPO examiners and opponents to challenge novelty when at least one divisional application has been filed in a family and where the claim(s) to be challenged represent a broadening in comparison to the priority application.

While T1496/11 specifically addressed the situation where the divisional was used to challenge its parent, the decision applies equally in the reverse scenario, such that a parent application may be citable against a divisional divided from it. Furthermore, there is no reason to suppose that the same rationale does not extend to sibling divisionals (multiple divisionals divided from the same parent) such that one divisional is available under Article 54(3) as novelty-only prior art against a sister (or brother) divisional application.

“Any European application claiming priority from an earlier European application could lack novelty if amendment resulted in a loss of priority.”

Since the 2010 changes to Rule 36 EPC (which limited the window of opportunity for filing divisionals at the EPO to 24 months from the first substantive office action) came into force, divisional applications are now being filed much earlier during examination than ever before, so that before an invalid priority claim has even been contemplated by the EPO, a divisional application which will go on to cause novelty destroying selfcollision may already have been filed and published.

Significance to life sciences

While the initial cases discussed above have not been in the life sciences field, the importance of self-collision is brought into sharp focus for life sciences applicants when it is remembered that a significant proportion of life sciences priority applications (and often the subsequent priority-claiming applications) are filed early in the product development cycle, often before full exemplification has been completed and usually without a specific commercial product having been identified.

Such early filings are ripe for more information to be generated during the priority year, potentially requiring a broadened disclosure when claiming priority. Furthermore, life sciences patent applications commonly receive multi-way unity objections due to the presence of multiple inventions within one application. It is therefore not unusual for life sciences applicants to file multiple divisional applications in one family.

Preventing self-collision

The issue of a self-colliding priority application can be avoided with relative ease by not allowing the priority application to publish in its own right. Simply put, any European patent application used to set a priority date should be withdrawn before publication.

In a perfect world, the prevention of self-colliding divisional applications is achieved by not filing divisional applications. However, patent applications are rarely drafted and filed in a perfect world and the need to file a divisional application is often unavoidable.

Therefore, for every European application where a divisional application has been or could potentially be filed, every claim amendment must be carefully considered to ensure that a valid priority is maintained, or at least commercially useful fallbacks, that clearly possess a valid priority, are included to enable amendment should the issue of self-collision arise later in examination.

In both cases, should the myriad of other commercial factors allow it, delaying filing of a priority application until adequate exemplification has been produced would reduce the risk of self-collision. Accordingly, careful consideration of filing and amendment strategies in light of these decisions will help applicants minimise the chances of falling into the self-collision trap.

Jane Wainwright is a partner at Potter Clarkson LLP. She can be contacted at: jane.wainwright@potterclarkson.com