Share this article:

EPO reconsiders meaning of “substance or composition” for medical use claims

By Michael Ford, Senior Associate

In this article, Michael Ford explores the evolving definition of ‘substance or composition’ in European patent law, with a focus on medical use claims, and the recent EPO decision T 1252/20, challenging established norms and its implications for patenting materials in biomedical innovation.

Get in touch 

Connect on LinkedIn


As a materials scientist by training, I have often been asked to define what a “material” actually is.  The Boards of Appeal at the EPO have also had to grapple with the similarly nebulous question: what is meant by the terms “substance or composition” as used in Articles 54(4) and (5) EPC concerning the novelty of medical use claims?  A recent decision, T 1252/20, has proposed a radical departure from the definition given in the European case law so far.

First and further medical uses

In Europe, it is not possible to obtain patent protection for surgical or therapeutic methods for treating, or diagnostic methods carried out on, human or animal bodies.  This exclusion is designed to maintain the freedom of medical practitioners when treating their patients.  However, according to Article 53(c) EPC, this restriction does not extend to “products, in particular substances or compositions” used in such methods.

According to Article 54 EPC, the EPO should also distinguish between certain types of biomedical innovation and other technologies when assessing patentability.  An invention is generally considered to be new if it is different from everything that has already been disclosed publicly in any way, anywhere in the world.  A patent claim to a known “substance or composition”, however, can be rendered novel by specifying its use in an excluded method of medical treatment or diagnosis, if the medical use itself is not already known.

In fact, the EPO provides protection for two different types of such use-limited claims covering substances or compositions.  A “first use” claim provides protection for the substance or composition for use in any method of treatment or diagnosis.  A “second” or “further use” claim provides more limited protection for the substance or composition for use in a more specific method of treatment or diagnosis.

For instance, a public disclosure of the structure of a molecule and its use in a non-medical application (e.g. as an anti-condensation coating on a glass window pane) would not prevent the molecule also being patented for use as a medicament generally, for example, if it were subsequently discovered that the molecule is useful as a cancer treatment.  In addition, the disclosure of use of the molecule in treating cancer would not prevent further patenting of the molecule for use more specifically in the treatment of pain.

Protection via first and further medical use claims, however, is only available where the product can be classified as a “substance or composition”.  The meaning of these terms is therefore an important question for determining the patentability of medical innovations.  For example, do these terms only cover pharmaceuticals and biologics, or do they also extend to materials like hydrogels, injectable fillers, dental restoratives or adhesion barriers?

Background case law

So far, most of the Technical Board of Appeal decisions on this topic have concluded that a material must include one or more chemical entities which function as an “active” ingredient in a method to qualify as a “substance or composition” within the meaning of Articles 54(4) and (5) EPC.  These decisions typically refer back to Enlarged Board of Appeal decision G 5/83 which, although not focused on the detailed meaning of “substance or composition”, repeatedly referred to the protection of “active ingredients” exerting “therapeutic activity” in the body.  The Boards have distinguished between chemically or biologically active substances (for example, a ligand for binding human immunoglobulin in T 2003/08) and products which achieve therapeutic effects via physical mechanisms (for example, a dialysis membrane in T 0773/10).

In a series of similar decisions (T 1758/15, T 2136/15 and T 1345/18), Boards found that injectable liquid products, which only achieved therapeutic effects after forming solid structures within the body, were to be classed as “initially viscous medical devices” rather than “substances or compositions” and so could not be protected through first or further medical use claims.  The Boards reasoned that the beneficial effects resulted from the physical properties of the 3D structures formed in the body, rather than the chemical nature of the formulations.  This case law has been incorporated into the current Guidelines for Examination at the EPO.

In one contrasting decision (T 0264/17), a Board of Appeal found that a biologically and chemically inert synthetic lubricant, for use as a synovial fluid replacement in diseased joints, did qualify as a “substance or composition” despite a total lack of activity.  The Board observed that the physiological effect of the lubricant was achieved by the complete lack of interaction with body tissue due to special omniphobic properties which arose from the chemical structure of particular perfluoropolyethers used in the composition.  The Board was therefore able to distinguish over the existing case law without criticising the basis of those earlier decisions.

T 1252/20

In new decision T 1252/20, however, a Board of Appeal has diverged significantly from the older case law.

This case concerned a composition comprising an amphiphilic peptide which forms a hydrogel under physiological conditions.  The inventors had found that it was possible to use this hydrogel to form blockages in biological vessels in the body to treat various medical conditions.  For example, a blockage could be used to deprive a tumour of a blood supply.  The patent claim required the use of specific peptides, defined in terms of amino acid sequences, in a specified concentration range.  The particular peptides, and the fact that they could form hydrogels, were already generally known, but the use of the resultant hydrogel in blocking a biological vessel in a method of treatment was not known.

The Examining Division had found that the claims lacked novelty because they were not entitled to be treated as purposed-limited medical use claims, following the earlier case law that the therapeutic effect was based exclusively on a macroscopic 3D structure formed after the peptide composition was introduced to the body.

The Board of Appeal, however, disagreed and concluded that the peptide solution was a “substance or composition” within the meaning of Article 54(5) EPC.  This conclusion was reached via various routes.

For Example, the Board noted that the European Patent Convention does not define “substance or composition” and decision G 5/83 cannot be relied upon to read any clear definition of the terms into the statute.  As discussed above, G 5/83 did not in fact consider the meaning of “substance or composition” in detail, since this was not disputed in the case at hand.

The Board also appears to have considered the plain meaning of the terms “substance” and “composition”.  It was emphasised that the patent claim defines a material in a liquid state, in the form of a solution containing peptides in specific amounts and concentrations, without any features typically characteristic of a device (such as shape).  The Board thought that a shapeless liquid mixture of chemical entitles was clearly not a device; it was a composition.

More fundamentally, the Board also found that there was no legal basis to require a chemical mode of action as a criterion for qualifying a material as a “substance or composition”.  For example, the Board noted that Article 54(5) EPC does not apply solely to methods of treatment by therapy – it also applies to treatments by surgery and to diagnostic methods.  Substances or compositions used in surgery or diagnostic methods will not necessarily have a mechanism of action comparable to the chemical activity of a drug.  The Board also highlighted that decision G 5/83 was specifically concerned with treatments by therapy and Swiss form claims directed at the “use for manufacture of a medicament”.  Although a medicament may require a chemically active component, Article 54(5) EPC is not limited to medicaments.  The Board further opined that the mechanism of action may not be understood in detail, or indeed at all, and the assessment of novelty should not hinge on this knowledge.

Finally, the Board concluded that the test in the case law so far does not achieve the original legislative purpose.  This was to provide a complementary form of protection for an otherwise recognisably useful invention in a field where, despite its excluded nature, technical development is otherwise highly desirable and beneficial and therefore patent protection should be available.

Further developments?

Decision T 1252/20 appears to depart radically from the existing case law on this topic and provides hope for applicants seeking to protect materials-related biomedical inventions in Europe.  However, it remains to be seen how this decision will be considered by Examining and Opposition Divisions, as well as other Technical Boards of Appeal.  This case also potentially opens the door for a referral to the Enlarged Board of Appeal for further, and perhaps final, clarification of the terms “substance or composition”.

I will be joining my colleague Isobel Finnie to discuss this topic in more detail in an upcoming webinar hosted by HLK’s Life Sciences and Healthcare team.  Look out for details on the HLK website and LinkedIn, or get in touch with us directly if you would like more information about this.

This is for general information only and does not constitute legal advice. Should you require advice on this or any other topic then please contact or your usual HLK advisor.

HLK bubble graphic HLK bubble graphic

Keep up-to-date with the latest IP insights and updates as well as upcoming webinars and seminars via HLK’s social media.