T 0941/16 - Three CDR's are not enough

 Key points

• For those working in the field of antibodies, the Board finds a claim for “an isolated monoclonal antibody or an antigen binding portion thereof ” specifying  some functional features and “at least three of the CDR sequences selected from the group consisting of the CDRs designated as CDR H1, H2, H3, L1, L2 and L3 as shown in Fig. 21” to be too broad and therefore insufficiently disclosed.
• The case is somewhat fact-specific, the difference in available evidence provides for a difference with T0617/07.
• See also brand new GL G-II 5.6.1.1: “Since the three CDRs of each of the variable domains of the light and heavy chains are normally responsible for binding to the antigen, the conventional antibody, ... needs to be defined by at least these six CDRs to fulfil the requirements of Art. 84.”(note, the present decision is about Art.83). (not sure how this new paragraph is supposed in Chapter G of the GL by the way).(see also new GL G-II 5.6.1.4 which more closely matches the claim at issue).
• This decision concerns the  Biogen type insufficiency, see CLBA II.C.5.4.
• The Board: “the issue is whether it is plausible, based on the evidence on file and taking common general knowledge into account, that a skilled person starting from the sequences of the murine scFv construct disclosed in Figure 21 of the patent application, and taking any arbitrary combination of three CDRs thereof in combination with three other structurally unrelated CDRs, will necessarily and reliably obtain antibodies showing the functional properties as defined in claim 1 by investing a reasonable amount of trial and error only”
• After a detailed review of various documents, the Board finds that “the presence of unmodified murine CDR H3 and CDR L3 in these humanised antibodies seems to be essential for retaining the functional properties defined in claim 1”.
• The Board: “In these circumstances, ... the general information in the patent application and the common general knowledge taken together, cannot be considered to provide the information necessary to allow the skilled person to reliably obtain substantially all of the claimed antibodies/fragments fulfilling the functional requirements of the claim. For particular combinations of CDRs (lacking an unmodified CDR H3 and CDR L3) it is not credible that a humanised antibody/fragment with the properties defined in claim 1 will be obtained. Readily performing the invention across the entire scope of the claim places an undue burden onto the skilled person.”

T 0941/16

https://www.epo.org/law-practice/case-law-appeals/recent/t160941eu1.html

decision text omitted.