Toxic Families

At the end of 2012 the European Patent Office (EPO) Boards of Appeal sent shockwaves through Europe when it concluded that a European divisional patent publication could be novelty destroying to the European parent patent from which it is derived.

The whole basis for what appears to be a nonsensical conclusion lies in the issue of entitlement to priority.  The deadly scenario generally will involve a priority European patent application P disclosing a specific embodiment or specific embodiments.  The subsequent European patent application EP claiming priority to P has a more general recitation in the claim(s).  As a result, the claim(s) of EP is broader than P and not considered entitled to the priority date.

A divisional European patent application is filed and subsequently published, which discloses an embodiment or embodiments identical to that appearing in P.  The specific embodiment(s) in the divisional publication that is entitled to priority is ruled to anticipate the broader claim(s) of EP that is not entitled under Article 54(3) EPC (earlier priority date but later publication).  Accordingly, the publication of the divisional application is found to anticipate EP.  

While the headlines focused on such toxic divisionals, indeed the possibility works both ways.  Parent European application publications can also be novelty destroying to European divisional claims not entitled to priority.  So the very act of filing one or more divisional applications could result in refusal or revocation of one or more, or even all, members of the same family.   

The Remedy of Partial Priorities

Enlarged Board of Appeal Decision G2/98 acknowledged that the same claim could have more than one priority date.  Specifically, the decision states, "The use of a generic term or formula in a claim for which multiple priorities are claimed in accordance with Article 88(2) EPC, second sentence, is perfectly acceptable under Articles 87(1) and 88(3) EPC, provided that it gives rise to the claiming of a limited number of clearly defined alternative subject-matters." (Emphasis added.)

The EPO Boards of Appeal have concluded in some cases that it is not necessary for explicitly defined alternatives to be spelled out in a claim nor that words such as "or" are present for different embodiments in a claim which have different priority dates and entitlements.

The remedy of partial priorities can work by construing the claim to have two alternatives, although not explicitly recited as such: (i) the embodiment(s) disclosed in both the subsequent European application and the priority application (P), and (ii) the remaining disclosures appearing in the subsequent European application but not the priority application (EP – P).

Alternative (i) is entitled to priority; hence, the European divisional or parent application cannot be considered Article 54(3) EPC prior art and is not novelty destroying.  Alternative (ii) is not entitled to priority, but the same disclosures appearing in the European divisional or parent application are also not entitled to priority.  Hence, again the parent or divisional application cannot anticipate the other.

Referral to the EPO Enlarged Board of Appeal

In an example of poisonous parents, T0557/13, the invention related to cold flow improver compositions. The divisional application was not considered entitled to priority and an example appearing in the parent application publication, which also appeared in the priority application and hence priority entitled, was considered a novelty–destroying disclosure under Article 54(3) EPC, and the divisional patent was revoked.

On appeal, the patent proprietor, the opponent, and the Board of Appeal all acknowledged that there has been divergent case law in this area.  Accordingly, it was agreed that there should be a referral to the Enlarged Board of Appeal to obtain clear guidance on how this issue should be addressed.

The questions now to be considered by the Enlarged Board of Appeal in G1/15 are:

1. Where a claim of a European patent application or patent encompasses alternative subject-matters by virtue of one or more generic expressions or otherwise (generic "OR"-claim), may entitlement to partial priority be refused under the EPC for that claim in respect of alternative subject-matter disclosed (in an enabling manner) for the first time, directly, or at least implicitly, and unambiguously, in the priority document?

2. If the answer is yes, subject to certain conditions, is the proviso "provided that it gives rise to the claiming of a limited number of clearly defined alternative subject-matters" in point 6.7 of
G 2/98 to be taken as the legal test for assessing entitlement to partial priority for a generic "OR"-claim?

3. If the answer to question 2 is yes, how are the criteria "limited number" and "clearly defined alternative subject–matters" to be interpreted and applied?

4. If the answer to question 2 is no, how is entitlement to partial priority to be assessed for a generic "OR"-claim?

5. If an affirmative answer is given to question 1, may subject-matter disclosed in a parent or divisional application of a European patent application be cited as state of the art under Article 54(3) EPC against subject-matter disclosed in the priority document and encompassed as an alternative in a generic "OR"-claim of the said European patent application or of the patent granted thereon?

These "poisonous" family members have certainly been a wake-up call for those filing divisional applications in Europe, and have identified the importance in careful claim drafting to ensure priority entitlement.  However, with the recent cases successfully utilizing the remedy of partial priorities and the referral to the Enlarged Board, we shall hopefully soon learn whether this ailment will continue to afflict us or be short-lived.

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