Extrication from the Stranglehold of Art. 123(3) EPC - T1360/11

The decision T1360/11 relates to a captious problem in relation to Art. 123(3) EPC (extension of the scope of a granted claim).

Presume that a claim defines a composition as comprising substances of Group A in a total amount of 1 - 10%, wherein Group A includes the substances A1, A2 and A3. Limiting claim 1 to the substance A1, i.e. to a composition comprising substance A1 in an amount of 1 - 10% would not exclude the presence of A2 and A3 - even in amounts higher than 10%. A composition with 10% of A1, 10% of A2 and 10% of A3 would be covered by claim 1 as amended but not by claim 1 as granted and therefore contravene Art. 123(3) EPC. According to the technical board of appeal, "This gives rise to a situation in which a way out for the patentee is anything but easy." (Reasons 3.1)

The technical board of appeal proposes the following solution (cited from the headword):

Where a granted claim directed to a composition defined in an open manner and including the presence of a component belonging to a class or list of compounds in a quantity defined by a range is later amended by limiting the definition of the class or list of compounds, a possible infringement of the requirements of Article 123(3) EPC may be avoided by including in the amended claim a quantitative condition on the limited class or list of compounds and an additional constraint on the total amount of compounds belonging to the broader class or list (point 3.11).

Translated to example mentioned above the claim would read composition comprising substance A1 in an amount of 1 - 10% , wherein the total amount of substances of Group A is 1 - 10%.