Human definitions versus biological reality (T 630/24)
Rose Hughes
As the recent furore over claim interpretation and description amendments illustrates, patent attorneys love nothing more than to argue about the meaning of words. As we know, words are contextual things, and can shift their meaning depending on the words around them and the perspective of the reader. Definitions are particularly unstable in biological sciences, where terminology is notoriously messy and governed by shifting evolutionary realities and historical naming systems. The case at issue in the recent Board of Appeal decision, T 630/24, arose out of one particular field of definitional shift within the life sciences, the distinction between the historical human defined genus versus the genetic reality of phylogeny. The case is really just a simple one of added matter, but nonetheless serves as a reminder of the care that always needs to be taken with biological terminology.
Legal background: Added matter
The standard for assessing added matter under Article 123(2) EPC at the EPO is the famously strict "gold standard", which requires that any amendment must be directly and unambiguously derivable by a skilled person, using common general knowledge, from the whole of the application as filed. There are many ways in which the EPO's application of the gold standard can trip up foreign applicants used to a more lenient standard for basis. Choices made at the drafting stage can often mean that, in Europe, claim amendments for important backup positions relying on a combination or selection of features lack basis.
One particular aspect of Article 123(2) EPC case law relates to the genus versus species selection. Generally speaking, in Europe, the disclosure of a specific species does not provide a valid basis for claiming a broader, overarching genus. This is considered an unallowable generalisation of the original teaching of the application as filed. Conversely, the disclosure of a broad genus is not considered a disclosure of every specific species falling within it. The genus/species distinction is not always immediately clear to those not familiar with the analogy from taxonomy. However, in the present case, the legal analogy finds an almost literal interpretation, with the Board of Appeal having to decide whether a biological, taxonomic genus could be removed to claim a broader phylogenetic classification.
Case background
The case in T 630/24 related to the application EP 3750549, from The University of Tokyo, directed to the use of certain bacteria to induce proliferation of regulatory T cells (Tregs). Tregs are a specialised subset of CD4-positive T cells that function to suppress abnormal or excessive immune responses and play a crucial role in immune tolerance and maintaining immunological homeostasis. The important part of the invention was the type of bacteria for stimulating these cells. Claim 1 on appeal specified a pharmaceutical composition for treating or preventing infectious diseases by inducing the proliferation or accumulation of Tregs, wherein the composition comprised bacteria belonging to Clostridium cluster XIVa and/or cluster IV.
The application was refused by the Examining Division (ED) for adding matter over the application as filed, specifically on the ground that there was "no single basis in the original application referring in general to bacteria belonging to Clostridium clusters IV/XIV as part of the invention without further limitation of such bacteria to the genus Clostridium".
The human gaze versus biological reality
Importantly, within taxonomy, a genus is a historic and human-invented taxonomic rank used to organize and name closely related species based on shared physical characteristics. A phylogenetic cluster (or clade), by contrast, is a strict evolutionary grouping that includes a single common ancestor and absolutely all of its genetic descendants, regardless of size or taxonomic rank. Whilst modern biologists have tried to ensure that every genus is also a valid phylogenetic cluster, discrepancies have occurred because many genera were named centuries before DNA analysis revealed the true evolutionary history of a group of organisms.
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| Genes apart |
Given that taxonomic categorisation began long before genetic analysis was possible, it is not surprising that many problems have been found with the initial categories. In the 18th Century, the biologist Carl Linnaeus used the genus Felis as a catch-all for almost every feline on Earth in his landmark book of zoological naming Systema Naturae. However, modern phylogenetics has forced scientists to drastically shrink this genus. Big cats such as lions and tigers have now been moved to their own distinct evolutionary branches (e.g. Panthera leo and Panthera tigris) leaving only domestic cats (Felis catus) and their closest wild cousins (e.g. Felis silvestris) in the original Felis group.
Similarly, DNA has also revealed that the original massive Chrysanthemum genus of flowers (also named by Linnaeus, in his earlier book Species Plantarum) was also an artificial grouping. Strict phylogenetic naming rules dictate that the "mums" popular with gardeners should be renamed to Dendranthema. However, in this case, the public backlash from florists and gardeners was so severe that botanists voted to bend the scientific rules so that famous flowers could keep their iconic genus name of Chrysanthemum. Not a case of Mum by any other name.
Defining bacteria without the genus
The present case centred on the distinction between the artificial grouping of genus versus phylogenetic group in the face of the strict EPO basis requirements. The applicant argued that Clostridium clusters XIVa and IV are phylogenetically defined groups of bacteria that encompass various taxonomic genera other than the genus Clostridium. As such, the applicant argued, referencing only the clusters was a justified intermediate generalisation over the original disclosure of the Clostridium genus, given that there was no inextricably linked structural or functional relationship between the taxonomic genus and the phylogenetic cluster.
The Board of Appeal was not convinced by this argument. Applying the case law on the gold standard, the Board of Appeal found that the information conveyed to the skilled person by the application as filed was that the active ingredient consisted of bacteria belonging to the genus Clostridium that induce the proliferation of Tregs, and that bacteria belonging to the cluster XIVa or cluster IV constituted a preferred subgroup of those bacteria.
The Board of Appeal reasoned that the phylogenetic classification defined a subset of the bacteria of the taxonomic group genus Clostridium. Because the clusters are broader and encompass other genera, the Board of Appeal found that omission of the limitation to the genus Clostridium extended the subject-matter to bacteria of all taxonomic genera within cluster IV or cluster XIVa and hence beyond the disclosure of the application as filed (r. 12).
The Board of Appeal thus concluded that omitting the classification into the genus Clostridium was not an intermediate generalisation, but rather a simple generalisation that improperly extended the claimed subject matter. The appeal was therefore dismissed.
Final thoughts
Leaving aside the specifics, this case is a reminder of how the EPO's strict added matter approach can be particularly challenging in the field of biological sciences. In biology, our knowledge of the hugely complex biological systems we are dealing with is constantly evolving (pun intended). Definitions within the field are therefore also constantly shifting in order to keep up with new discoveries and developments. One particularly notable example that caused issues, for example, was the widespread use of the term "genetically modified" which became outdated and overly narrow following the development of the functionally related, but technically and definitionally distinct, techniques of "gene editing" such as CRISPR-Cas9. Defining anything biological in the field of cell therapy is also fraught with risk, given the constantly shifting landscape of definitions (IPKat).
The problem for the applicant in the present case, however, was not really one of shifting biological definitions, but of drafting. The Board of Appeal just considered the application as filed to lack the basis for the alternative definition of the bacteria, which could have been avoided by including descriptive basis for the preferred embodiment. Hindsight is a wonderful thing, but generally of no help at the EPO.
Further reading
- The UPC's approach to added matter and functional claims (Abbott v. Sibio Technology, UPC_CoA_382/2024) (March 2025)
- Pitfalls of cell therapy manufacturing IP - A case study (T 0868/23) (July 2025)
- The unforgiving gold standard: Why deleting a feature can add matter at the EPO (T 0422/23) (Sep 2025)
- A new way to define T cells and what it means for cell therapy IP (Jan 2026)