In G 1/15, the EPO's Enlarged Board of Appeal was
asked to clarify the position regarding the entitlement to
"partial priority". A key issue was whether it is
necessary for subject matter to be defined as alternatives in a
claim in order for the claim to be entitled to multiple priority
While the full decision in G1/15 is not yet out, the
Enlarged Board has issued an order to the effect that the only
aspect that needs to be considered is whether the subject matter
claimed is disclosed in a priority document. This possibly more
liberal approach to partial priority may be good news for many
"Partial priority" arises when a claim in a patent or
application is not identical to the text in its priority
application so that some of the claim, but not all of it, is
entitled to the earliest priority date, and the remainder of the
claim is entitled to a later date. Typically, this arises when a
claim is broadened between the priority filing and the filing of
the application itself.
A very strict approach to partial priority has been taken by
some EPO Boards of Appeal such that a claim is considered only to
be entitled to multiple priority dates when it is divisible into
clearly defined alternative subject matters (e.g. A OR B).
Thus entitlement to partial priority is denied unless the
disclosure of the priority document can be identified as a clearly
defined alternative from within the claim.
This approach has led to harsh consequences, with even minor
broadening of a claim leading to the entire claim losing
entitlement to priority. As a consequence, any disclosure of the
content of a priority document during the priority year could
deprive the claim of novelty. A particularly bizarre outcome was
the "poisonous divisional" situation in which the filing
of a divisional application could render a parent application
invalid. See our article:
Demystifying Self-collision at the EPO for more details.
The Enlarged Board's order
In case G1/15, the Enlarged Board was asked to clarify whether
the strict approach outlined above was correct or whether a more
liberal approach to "partial priority" was required.
Further details on the referral to the Enlarged board can be found
in our article EPO
Enlarged Board of Appeal to tackle divisional poisoning.
Although the full decision is not yet out, the following order
has been issued:
"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."
Thus, a claim may not be refused multiple priority dates just
because it uses a generic term and does not include the subject
matter of the priority document as a clearly defined alternative.
Instead the sole consideration is what is disclosed in the priority
The Enlarged Board has thus adopted a more liberal
interpretation of the requirement for entitlement to priority.
Denial of partial priority and the harsh consequences that ensue
may now be less common. In particular, members of the same patent
family that share common priority applications are less likely to
deprive each other of novelty.
This is potentially good news for many applicants.
We will report further when the full text of the decision is
The content of this article is intended to provide a general
guide to the subject matter. Specialist advice should be sought
about your specific circumstances.
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