At the European Patent Office, the principle of res
judicata dictates that matters decided on by a Board of Appeal
are binding on the Opposition Division in any subsequently resumed
proceedings. In T 0308/14, a Board of Appeal had to decide on
whether a finding of insufficiency by the Opposition Division
violated the principle of res judicata.
T 0308/14 was the second appeal concerning EP 1 578 879, which
related to an extended polyacrylic acid based binder
composition.
In the first instance proceedings, the Opposition Division decided
to revoke the patent on the grounds that all of the claim requests
on file contained added subject matter. This decision was
subsequently appealed by the proprietor.
During the appeal proceedings (T 1115/10), the issue of clarity
under Article 84 EPC was also considered by the Board. The
respondent (opponent) had argued that the feature of
"polysaccharides having a weight average molecular weight of
not more than 10,000" in Claim 1 of the second auxiliary
request, which was not present in the claims as originally granted,
lacked clarity, as there was no disclosure in the specification on
how to determine the weight average molecular weight of the
polysaccharides, and it was common general knowledge that weight
average molecular weight values could vary depending on the method
by which they were measured. Naturally, the appellant (proprietor)
disagreed, and argued that there was no evidence that different
measurement methods gave rise to different weight average molecular
weight values.
In arriving at its decision, the Board acknowledged that weight
average molecular weight values may depend on the measurement
method applied as far as high molecular weights are concerned (eg
500,000 or higher). However, the Board stated that no proof had
been provided that the same dependence exists for low-weight
average molecular weights of not more than 10,000. Thus, taking
into account the evidence on file, the Board sided with the
appellant and held that the weight average molecular weight of not
more than 10,000 was clear as there was no proof that it depended
on the measurement method applied. As the second auxiliary request
was also held to meet the requirements concerning added subject
matter, the Board remitted the case back to the Opposition Division
for further examination.
In the course of the subsequent opposition proceedings, the
opponent argued that the patent lacked sufficiency due to the lack
of a measurement method for the weight average molecular weight in
the patent. The opponent also filed documentary evidence showing
that weight average molecular weight values for polysaccharides
depend on the measurement method. In the light of this evidence,
the Opposition Division concluded that the claims of the previous
second auxiliary request – now the main request –
lacked sufficiency because the method of measurement was essential
to enable the skilled person to work the invention.
The proprietor appealed the decision of the Opposition Division and
argued that the sufficiency objection regarding the weight average
molecular weight of the polysaccharides could not succeed since the
question of whether this feature was clear had already been decided
by the board in T 1115/10 and therefore constituted res
judicata.
In T 0308/14, the Board noted that the Opposition Division's
decision to reject the claims as lacking sufficiency was "a
decision in insufficiency arising out of ambiguity, namely the
ambiguity of the weight average molecular weight of the
polysaccharides in claim 1". The Board went on to note that
the binding effect of T 1115/10 does not only concern the decision
on clarity as such, but extends to any finding of fact that led to
this decision, eg the finding of fact that that the weight average
molecular weight of not more than 10 000 in claim 1 was clear
since, taking into account the evidence on file, it did not depend
on the measurement method applied. Since the Opposition
Division's finding of lack of sufficiency started from the
opposite assumption, the Board found that the Opposition Division
had violated the principle of res judicata. As such, the
Board found the requirement of sufficiency to be met.
Ultimately, the appeal was dismissed as the claims on file were
found to lack an inventive step. Therefore, the decisions of the
Board in T 1115/10 and T 0308/14 in respect of clarity and
sufficiency had no bearing on the final outcome of the case.
However, had an inventive step been acknowledged, the failure of
the opponent to support its observations on clarity with
documentary evidence earlier in the proceedings would have (to the
detriment of the opponent) resulted in the allowance of claims that
were arguably unclear and insufficient.
To conclude, it appears that the decision of the Board in T 0308/14
has implications that reach beyond the specific interrelated issues
of clarity and sufficiency. Indeed, it suggests that the principle
of res judicata may extend to any finding of fact made on
the way to a decision of a Board of Appeal and is not just limited
to the decision itself.
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