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December 22, 2023 - European Union, Asia, Healthcare

Standards for Inventiveness and Disclosure for Antibody Claims Across Jurisdictions

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Standards for patenting antibodies have substantially tightened over the last few years restricting scope of antibody claims—or, in some cases, undermining the validity of granted patents. Most recently, Singapore updated guidelines to add a framework for analysis of antibody patentability. Although not all countries have written guidelines, this framework generally aligns with standards in other countries.

New sections 8.192-8.193 were introduced to the Examination Guidelines by the Intellectual Property Office of Singapore (IPOS) and set out an examination framework for assessing novelty and inventive step of antibody inventions. In particular, the guidance states that “for an antibody binding the same antigen as known antibodies, inventive step is not acknowledged based solely on its characterization by its CDR sequences.” Instead, the IPOS guidelines require that the specific amino acid sequence of an antibody must impart an additional surprising property compared to known antibodies binding the same antigen for it to be non-obvious. Description in the specification of a surprising technical effect associated with the claimed antibody is helpful to finding an antibody sequence inventive.

The new guidelines issued in Singapore reflects a trend seen in other jurisdictions.

In the United States, although there is no specific issued guidance for consistent examination of antibody claims, some examiners find claims obvious if the only difference from the prior art is the sequence, in which case data showing a superior activity may be helpful. Other examiners may consider sequence difference sufficient to confer non-obviousness. In contrast to the lack of standards for assessing non‑obviousness of antibodies in the United States, there is a more consistent and higher standard for written support for antibodies, making it challenging to obtain claims broader than exact sequences. For instance, claiming sequence identity (for example, to CDRs or the variable regions) is unlikely to be patentable unless the application discloses a sufficient number of examples that can support the breadth of the claims.

To establish inventive step of novel antibody sequences, the European Patent Office (EPO) requires a surprising technical effect is shown by the application, or that there is no reasonable expectation of success of obtaining antibodies having the required properties (Section G-II.5.6.2 of Guidelines for Examination). In contrast to the United States, standards for establishing support for antibody claims are generally not as strict at the EPO. Nevertheless, it is generally required to define the antibodies by reference to the CDRs, but often examiners will also ask for full variable sequences to be included (e.g., if binding affinity is the technical effect).

In China, the applicant needs to show that the claimed antibody has beneficial technical effects (rather than unexpected technical effects) compared to the known antibody. This may mean that it is not necessarily required to show that there is a special technical effect (e.g., binding affinity) and/or to have comparative data over the known antibody. Regarding the level of disclosure required for obtaining a genus claim, an antibody claim is required to be defined by at least the sequences of the six CDRs of the antibody. It is difficult to obtain a genus claim (e.g., antibodies defined by an epitope or only some CDRs of the heavy chain and/or light chain), and it is nearly impossible to obtain functional claims that are not limited to specific antibody sequences.

Similar to all the jurisdictions above, applicants in Japan can rely on unexpected superior properties to overcome an obviousness rejection. Such unexpected superior property can be shown by the demonstrative data in the application as filed. The written description and enablement requirements in Japan generally align with those in the United States and China, in that a sufficient number of embodiments needs to be described in order to pursue a genus claim. Notably, the presence of any negative data in an application in Japan can evidence inoperative embodiments and—if such is within the scope of the claim—may also limit the ability to claim a broad genus.

While the standard to inventiveness and written support for antibodies vary across jurisdictions, the trend toward tightening patentability standards is clear, making it even more important to have data characterizing the antibody of interest in the specification. The data in the specification can do double duty—providing both fodder for inventive step (especially if data comparing to the prior art are available) and evidence to support enablement and written description.