At the end of 2012, a European Patent Office (EPO) Board of Appeal decision sent shockwaves through Europe; it concluded that a European divisional patent publication could be novelty destroying to the European parent patent from which it is derived, the so called “poisonous divisional.”

The reasoning behind the “poisonous divisional” is that the parent claims are not entitled to priority, whereas the anticipatory subject matter in the divisional publication is entitled to priority. In fact, the problem works both ways, i.e., the publication of the parent could also be novelty destroying against a divisional application whose claims are not entitled to priority.

Some EPO Board of Appeal decisions avoided this problem by treating claims as having two conceptual parts. One part is entitled to priority, hence the European divisional or parent cannot be novelty destroying. The second part is not entitled to priority, but the same disclosures appearing in the European divisional or parent are also not entitled to priority. Therefore, the parent or divisional application cannot anticipate the other. Other decisions did not.

Due to the divergent EPO Board of Appeal case law on the “poisonous” issue, five questions were referred to the Enlarged Board of Appeal (EBA), EBA referral G1/15. The first question addressed whether entitlement to such partial priority could be refused for a claim with a generic expression which encompasses alternatives, but which does not explicitly separate the alternatives in the claim.

The EBA has this week issued an order of the decision for this referral addressing the first question. The order can be found here and states:

Under the EPC, entitlement to partial priority may not be refused for a claim encompassing alternative subject-matter by virtue of one or more generic expressions or otherwise (generic “OR”-claim) provided that said alternative subject-matter has been disclosed for the first time, directly, or at least implicitly, unambiguously and in an enabling manner in the priority document. No other substantive conditions or limitations apply in this respect.

The detailed reasons for this order are forthcoming. While we wait for those, by answering “no” to the first of the G1/15 questions, the remaining questions do not need to be addressed, and it looks like this issue of “poisonous” family members will be short-lived and can be finally put to rest.

Further background and information on G1/15, “poisonous divisional,” and the “remedy” of partial priorities can be found here.