6.2 5.6.2 Inventive step of antibodies

The subject-matter of a claim defining a novel, further antibody binding to a known antigen does not involve an inventive step unless a surprising technical effect is shown in by the application or unless there was no reasonable expectation of success of obtaining antibodies having the required properties (cf see also G‑VII, 13). Examples of surprising technical effects when compared to known and enabled antibodies are, for example, include an unexpected improvement over prior-art antibodies in one or more properties, such as an improved affinity, an improved therapeutic activity, a reduced toxicity stability or immunogenicity, an unexpected species cross-reactivity or a new type of antibody format with proven binding activity or an unexpected property not exhibited by prior-art antibodies.

If inventive step of a functionally defined antibody relies on an improved property versus the enabled antibodies of the prior art, the main characteristics of the method for determining the property must also be indicated in the claim or indicated by reference to the description (F‑IV, 4.11.1).

If the surprising technical effect involves the binding affinity, the structural requirements for antibodies inherently reflecting this affinity must comprise the required CDRs and the framework regions because the framework regions also can influence the affinity.

If a novel antibody binds to the same antigen as known antibodies, inventive Inventive step is not acknowledged solely on the basis that the novel an antibody is structurally different from the known prior-art antibodies. Arriving at alternative antibodies exclusively by applying techniques known in the art is considered to be obvious to the skilled person. The fact that the structure of the thus obtained alternative antibodies an antibody, i.e. its their amino acid sequences sequence, is not predictable is not a reason for considering these antibodies the antibody as non-obvious (see T 605/14, section 24; T 187/04, section 11).

Nevertheless, antibodies can be inventive if the application overcomes technical difficulties in generating or manufacturing the claimed antibodies. A novel type of functional antibody format may also be considered inventive.