Patent protection for new medical uses of known materials before the European Patent Office: it’s all about the technical reality

This article is written by Annelies De Clercq. 

Nowadays, treatments of patients both by therapy and surgery have evolved into very specialized methods involving innovative therapeutic agents, sophisticated medical devices, and often combinations thereof.

When an invention relates to a novel and inventive product useful in medicine, this can typically be protected by a claim to that product. However, many valuable inventions relate to novel therapeutic, surgical or diagnostic applications of known products. A novel in vitro diagnostic use can be protected by a corresponding method or use claim. The European Patent Office (EPO) however will not grant patents for methods for treatment by surgery or therapy or in vivo diagnostic methods. The rationale behind this exception is to allow medical and veterinary practitioners to use their skills and knowledge of the best available treatments to achieve the utmost benefit for their patients uninhibited by any worry that some treatment might be covered by a patent.

To encourage innovators to research and discover medically useful applications for known substances and compositions, in Europe, a known substance or composition may be claimed for use in a surgical, therapeutic and/or in vivo diagnostic method if the substance or composition has not previously been disclosed for use in any such method (referred to as “first medical use”). A first medical use claim can be formulated as “Substance or composition X for use as a medicament” or “... for use in surgery/therapy/in vivo diagnostics”.

In addition, if the known substance or composition was previously disclosed for use in surgery, therapy or an in vivo diagnostic method, a European patent may still be obtained for any second or further use of the substance or composition in these methods provided that said use is novel and inventive (referred to as “further medical use” or “second medical use”). A claim to a further medical use of a known substance or composition can be formulated as: “Substance or composition X for use in treating disease Y” or “… for use in a method of treatment of disease Y”.

Importantly, in Europe, first and second medical use claims are available only for substances or compositions but not for other types of products such as medical devices.

Given the importance of the distinction between a substance or composition versus other products, the key question is how the EPO looks at the interpretation of “substance or composition”.

For many products, such as an active agent used in a therapeutic method, it is quite clear-cut that they act as a substance or composition in a method of treatment by therapy. For other products such as medical devices, the EPO has developed its own case law, which is discussed here . Over the years, however, many materials and products such as organic nanoparticles, liposomes, quantum dots, polymeric crosslinkable biomaterials, dental filling materials, cements, gels, etc. have been developed for which it is not always clear whether they qualify as a “substance or composition” or as a device.

With reference to case law decisions G 5/83 and T 1758/15, the Guidelines for Examination in the EPO provide an insight on the interpretation of a “substance or composition” in the context of medical use claims. A product is said to qualify as a “substance or composition” if it is the active agent or ingredient in the specific medical use and if the therapeutic effect can be ascribed to its chemical properties. As an example, reference is made to a filler material which is injected between a first tissue targeted for radiation treatment and a second sensitive tissue which is desired to be protected from radiation. If the shielding effect of the filler material is achieved by a mere mechanical displacement of the sensitive tissue relative to the target tissue, e.g. due to the volume it occupies between the two tissues, the filler material qualifies as a “device” rather than a “substance or composition”. On the other hand, if the filler material produced a radiation-reducing effect on the sensitive tissue which could be attributed to its chemical properties, it would be considered as a “substance or composition”.

The example above shows that the same material may or may not be seen as a “substance or composition” for use in a medical method depending on how the material exerts its medical effect. It seems that when the therapeutic effect of a material could be ascribed to its chemical properties, the material will be considered as a “substance or composition” within the context of medical use claims.

This principle is confirmed by another piece of case law of the Boards of Appeal. In decision T 2003/08, the Board allowed a claim directed to a column comprising a ligand for a new use in an extracorporeal treatment. The Board considered, in accordance with the reasoning in decision G 5/83 and in view of the claim which relates to the treatment of patients by therapy, that it is decisive for determining whether or not a “substance or composition” is used in a treatment to establish (a) the means by which the therapeutic effect is achieved and (b) whether that which achieves the therapeutic effect is a chemical entity or composition of chemical entities. In the case at issue the medical effect on which the treatment according to claim 1 was based was the removal of immunoglobulin from the plasma of patients suffering from dilated cardiomyopathy. This effect was achieved by the specific ligand for human immunoglobulin, which was undisputedly a chemical (biological) entity. The column only served as a carrier for the ligand and was not instrumental in achieving the therapeutic effect. Accordingly, the Board held that the means used for the treatment in accordance with claim 1 was to be considered as a “substance or composition” within the meaning of decision G 5/83.

Further case law of the Boards of Appeal confirms the approach that the technical reality of a case determines whether a product is defined as a “substance or composition” within the context of medical use claims.

In decision T 773/10 claim 1 was directed to a dialysis membrane for use in the treatment of multiple myeloma. In the Board’s view, the claimed dialysis membrane did not contain any further substance or composition which might constitute an “active” ingredient within the meaning of decision T 2003/08. The claim could not be considered a further medical use claim.

In T 264/17 the Board found that the claimed lubricant for replacing synovial fluid was a “substance or composition”. The therapeutic effect of the claimed perfluorinated polyethers lay in their acting as a replacement for synovial fluid in diseased joints. In the Board’s view, this effect was achieved as a result of the claimed lubricant’s material properties.

The ensuing decisions also confirm and further define the approach that a product qualifies as a “substance or composition” if it is the active ingredient in the specific medical use and if the therapeutic effect can be ascribed to its chemical properties as opposed to its mechanical or physical properties, shape, dimensions, structure or positioning.

In decision T 1099/09, the claim related to a strip made of biocompatible material for use in the treatment of urinary incontinence in a woman. The strip in question was a finished product with a given shape and dimensions. In this case, the strip was made from polypropylene. The Board did not consider the “strip” as a “substance or composition” because the therapeutic effect did not derive from the nature of the material but depended on the geometry and positioning of the strip.

Decision T1069/11 related to a stent for use in prevention of restenoses of a wall of a blood vessel having atheromatous plaque. The stent consisted of a multilayer braided framework devoid of any cover layer. Accordingly it was a finished product having a certain shape and certain dimensions and which did not comprise any active ingredient. Hence, the Board considered that the claimed stent did not qualify as a substance or a composition.

Case law has shown that the same principle towards defining a “substance or composition” applies not only to therapeutic methods but to any of the methods for treatment of the human or animal body by therapy or surgery and diagnostic methods practised on the human or animal body. For example, in decision T 826/06, a dye (in this case a well-defined chemical) was used for selectively staining the outer surface of the anterior lens capsule of the eye, thereby providing a clear distinction between the portion of the anterior lens capsule that was to be removed and the underlying lenticular material. This distinction facilitated the controlled opening of the anterior lens capsule. In this case, the dye was (a) the means by which the selective staining facilitating the surgery was achieved, and (b) a chemical, thus qualifying as a substance or composition in the context of medical use claims.

From the discussion above, the accepted approach towards defining a “substance or composition” may seem to be fairly consistent. However, an issue may arise in case a treatment is based on a combination of chemical properties and mechanical properties of the substance or composition. For instance, how would the filler material of the above example from the EPO Guidelines be defined in case the proper functioning of the filler material would require binding to the sensitive tissue (i.e., interaction with the body based on the material’s chemical properties) before being able to perform its function of mechanical displacement of the sensitive tissue relative to the target tissue (mechanical properties).

When such a situation arises, in our experience, it is of utmost importance to describe in the application the interaction of the material with the body. Such a statement of interaction based on the chemical properties of the material may be appropriate to qualify the material as a “substance or composition” within the context of medical use claims.

Irrespective of the above, it appears that the interpretation of a material as a “substance or composition” by the EPO still precludes the protection of a significant number of inventions – which could provide important health benefits – based on how the material performs its medical effect. It is unfortunate that patent protection is denied for a new therapeutic indication or surgical use of what undeniably is a substance or composition based only on the fact that its medical effect is rooted in its physical or mechanical properties. Likewise, it would be beneficial for society that medically useful products and materials which currently do not fall within the EPO’s interpretation of a “substance or composition” can be commercially developed while being backed up by patent protection. This would however require a significant change in the views of the Boards of Appeal.

To conclude, for an invention relating to a new medical application of a known material it cannot be automatically assumed that the first or second medical use claim format will be available. Rather, one must evaluate whether the material will be likely interpreted as a substance or composition in the context of a medical method and the new medical application will be taken into account for the novelty assessment. To do so, the technical reality of the case under consideration needs to be studied and the following needs to be determined: (a) the means by which the medical effect is achieved and (b) whether that which achieves the medical effect is a chemical entity or composition of chemical entities. If the medical effect can be ascribed to the material’s chemical properties, then protection can be available using the first or second medical use claim format. Under the EPO’s current approach this remains a case-by-case analysis centered on the technical reality of the invention. Our experienced team of European patent attorneys at De Clercq & Partners can help you select the most suitable ways to protect your inventions in the medical field. Please reach out to us at info@dcp-ip.com.