Upon discovery of a novel biological target, for example in a newly characterised pathway, it is fairly common to attempt to patent protect an antibody directed to the novel target. Such claims are often very broadly provided as “an antibody” (i.e. an antibody of any structure/sequence) that is capable of binding to a specified target antigen. This is on the premise that if an important novel target antigen is discovered and characterised, then the targeting of such a target antigen can lead to a therapeutic or diagnostic outcome, and that this should be patentable. In the past, there has been the ability to claim such antibodies without actually generating or identifying the antibodies and providing data (i.e. a description of the antibody), provided that there was sufficient information and data provided on the target antigen.

However, following a recent Amgen Inc. v. Sanofi (Fed. Cir. 2017) decision, a memorandum has been provided to USPTO Examiners to clarify Written Description requirements in the US. The memorandum states that “[i]n view of the Amgen decision, adequate written description of a newly characterized antigen alone should not be considered adequate written description of a claimed antibody to that newly characterized antigen.” (emphasis added). This essentially clarifies that, in the US, broad antibody-to-target claims without any supporting written description will likely face rejection.

In contrast, there is no similar direction in Europe, where broad antibody-to-target claims should remain theoretically achievable. However, there are hurdles to successfully claiming a broad antibody-to-target, where difficulties can often arise from the prior art. For example, the EPO have long established that antibody generation/isolation is now routine and that an antibody to a given target could be routinely generated by a skilled person. This can work in the patentees favour for avoiding a sufficiency objection (i.e. the EPO equivalent to the US Written Description requirement) where there is no data for an actual antibody against the target in the application as filed. However, if the target has been disclosed in the prior art, this presumption by the EPO that antibody technology is now routine can result in an objection to a lack of inventive step. Therefore, the absolute novelty of the target antigen can be critical to such claims, and this becomes increasingly difficult in the age of an explosion of information on biological pathways.

It is also important to consider the value of broad antibody-to-target claims for covering antibody based therapeutics. Often the identification of a novel biological pathway or target is early in the timeline of a therapeutic, which can take approximately 10-15 years to reach the market from initial target validation. Therefore, there could be limited patent term left to cover the marketed product without further applications for supplementary protection certificates (SPCs). Diagnostic based antibodies may be less impacted because they can face a shorter timeline. Of course, the type of business involved is important, where a spin-out or SME seeking investment and grant funding would potentially find higher value in an early patent relative to big-pharma who can afford to sit on the information and develop a lead antibody to be later patent protected.

The patent protection of every new discovery and target validation should be considered on a case by case basis.