EPO Guidelines on Antibodies: an assessment of adherence In March 2021, the European Patent Office (EPO) Guidelines for Examination were updated to include a section devoted to the examination of antibodyrelated patent applications (Guidelines G-II, 5.6). This new section provided a much anticipated outline of the EPO requirements for different approaches to defining antibodies in patent claims (Guidelines G-II, 5.6.1) and helpful guidance in relation to the inventive step of antibodies in Europe (Guidelines G-II, 5.6.2). The new antibodies section of the EPO Guidelines was discussed in detail in our article “An antidote to antibody patent confusion in Europe”. Here we look at the effect the new Guidelines have had on the prosecution of antibody patent applications over the last year Antibodies are typically in the form of immunoglobulin G and comprise a Y-shaped protein consisting of two identical light chains and two identical heavy chains, each folded into constant and variable domains. Each of the heavy and light chain variable domains (referred to as VH and VL) contains three hypervariable regions, referred to as “complementaritydetermining regions” (CDRs), which together provide the antigen-specific binding interface. In the March 2022 revision of the EPO Guidelines, amendments to the antibody sections have been made. However, these changes are relatively minor, and appear to be generally intended only to more explicitly acknowledge the patentability of unconventional immunoglobulin structures, such as heavy-chain-only antibodies and antibody derivatives, such as antibody fragments, bispecific or multi-specific antibodies, and antibody fusion products. Since the introduction of the new antibody Guidelines in March 2021, the EPO has granted in the region of 300 patents relating to new antibodies 4
and antibody derivatives. We have analysed the claims of these granted patents to investigate how EPO Examiners have started implementing the new antibody Guidelines, and in the following brief review, a number of emerging trends and perspectives are discussed. As an initial observation, very few antibody patents granted since the introduction of the new Guidelines (less than 5%), define the antibodies in terms of their method of production, such as reciting an immunisation strategy, or on the basis of a deposited hybridoma. The vast majority (about 85%) of all antibody patents granted in this period define the antibody, at least in part, on the basis of an amino acid sequence of the antibody. Of these patents, about 55% recite in the granted claims the sequences of all six CDRs. A further 40% recite the full heavy and light chain variable domain sequences, and about 2% recite the full antibody sequence in the claims. In view of these figures, it seems that it is becoming increasingly challenging to obtain a broad scope of patent
protection, without reciting at least the sequences of all six CDRs.
Since the “introduction of
the new antibody Guidelines in March 2021, the EPO has granted in the region of 300 patents relating to new antibodies and antibody derivatives.
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The Guidelines state that it is possible to define an antibody on the basis of less than 100% sequence identity to the variable domains or CDRs when this feature is combined with a functional feature. This appears to be the most common approach taken by antibody patentees, and about 55% of granted patents define the antibody
