Review Of EPO Antibody Decisions In 2023

J A Kemp LLP


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Last year we provided a review of 19 EPO Board of Appeal decisions relating to "antibody inventions" that were published between January and December 2022. We have now reviewed the decisions published in 2023.
UK Litigation, Mediation & Arbitration
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Last year we provided a review of 19 EPO Board of Appeal decisions relating to "antibody inventions" that were published between January and December 2022. We have now reviewed the decisions published in 2023.

Before discussing these decisions, we should first briefly mention G 2/21, which is a decision by the Enlarged Board of Appeal published in March 2023. G 2/21 considered whether post-published evidence could be used to prove the existence of a technical effect when assessing inventive step. The decision confirms that post-published evidence can in principle be used, but only when the skilled person, with the common general knowledge in mind, and based on the application as originally filed, would derive the technical effect as being "encompassed by the technical teaching" of the originally disclosed invention.

Post-published evidence can of course be important for any invention, but the decision in G 2/21 is particularly relevant for medical use claims. It confirms that post-published data can be relied upon as evidence of a therapeutic effect when considering the inventive step of such claims, but only if it is credible from the application as filed that said effect would actually be achieved. It remains to be seen whether this "credibility threshold" will be assessed more or less strictly than previous approaches to this question, which required an effect to be "plausible". In any case, the impact of G 2/21 on claims to therapeutic uses of antibodies may be more significant than for other pharmaceuticals, because it is still relatively common for antibody patent applications to be filed with no (or only minimal) direct evidence of a therapeutic effect. As such, we expect to see a steady flow of Board of Appeal decisions in the coming years in which the outcome turns on the ability of the proprietor to rely on post-published evidence for the therapeutic effect of an antibody.

Turning back to Board of Appeal decisions published in 2023 that relate specifically to "antibody inventions", we identified 18 such decisions. We do not believe that any of these decisions represents a significant shift in EPO practice, nor that any of them will compel changes in the way that examination is conducted.

In our view it remains the case that antibody inventions are not treated differently at the EPO to any other forms of technology. In decisions where "antibody-specific" considerations may be applied, the EPO has done this consistently and in line with the (now largely established) basic principles that are further explored in our advanced guide to drafting and prosecuting antibody inventions at the EPO. The majority of the 2023 decisions support the current practices of the Examining Divisions that we observe in routine prosecution, and which were partly codified in a dedicated section of the EPO's Guidelines for Examination (G-II, 5.6; first issued March 2021 and revised subsequently – also discussed in our advanced guide).

On a day to day basis the Guidelines may remain a more important source of guidance than the case law, but the 18 decisions covered in this review nonetheless provide confirmation and consolidation of EPO practice, represent useful examples of fact patterns for future reference, and may also help to illustrate developing trends. One of these trends is the increasing number of cases relating to "downstream" developments of existing antibodies, particularly for treating subgroups of patients and specific dosing regimens.

Interestingly, we have continued to see evidence over the year that the EPO is willing to allow broad antibody claims under certain circumstances, for example where the antibody is defined by its epitope. This type of definition is narrower than a claim directed broadly to an "anti-target" antibody, but it provides greater coverage than claims which define the antigen binding domains or complementarity-determining regions (CDRs) by their specific amino acid sequence ("2nd generation" antibody claims). As such, claiming an antibody by its epitope sequence is becoming more popular with applicants looking to capture some additional breadth for antibody variants. This will be encouraging for applicants who may have been forced to accept relatively narrow, structurally-defined antibody claims in the USA and are looking to obtain broader coverage in Europe. We have seen a number of decisions in 2023 which relate to epitope-defined antibodies and we anticipate more Board of Appeal decisions on this point in the future.

Below we provide some statistics from the 18 decisions and discuss some of the more interesting cases in detail.

J A Kemp LLP acts for clients in the USA, Europe and globally, advising on UK and European patent practice and representing them before the European Patent Office, UKIPO and Unified Patent Court. We have in-depth expertise in a wide range of technologies, including Biotech and Life Sciences, Pharmaceuticals, Software and IT, Chemistry, Electronics and Engineering and many others. See our website to find out more.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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