5.6.1.1 Definition by structure of the antibody 

Since the three CDRs of each of the variable domains of the light and heavy chains of an IgG are normally responsible for binding to the antigen, the IgG conventional antibody, in order to be uniquely defined by its structure only and have its characteristic binding specificity, needs to be defined by at least these six CDRs the number of CDRs required for its binding to fulfil the requirements of Art. 84.

CDRs when not defined by their specific sequence must be defined according to a numbering scheme, for example, chosen from that of Kabat, Chothia or IMGT.

If a conventional antibody an IgG is defined by fewer than the six sequences of the six of its CDRs, the claim will be objected to under Art. 84 because it lacks an essential technical feature. unless A claim to an antibody defined by its structure by fewer than six CDRs will be considered to fulfil the requirements of Art. 84 only if it is experimentally shown that one or more of the six CDRs do not interact with the target epitope or if it concerns a specific antibody format allowing for epitope recognition by fewer CDRs.