Navigating product-by-process claims at the European Patent Office

Inventions in the field of chemistry often relate to the discovery of a new product that has been found to have improved properties over known products. However, it is not always straightforward to clearly define such products purely in terms of their physical characteristics. Often, the microstructure of the product is unknown, or is too difficult to clearly describe, such that a structural definition may be inadequate for capturing the true scope of the invention.

As those familiar with the patent process will know, an alternative approach for defining these products in patent applications is using so called “product-by-process claims”, which define the product in terms of the process by which it is made, e.g. a product X obtainable by process Y. While these claims can be a useful tool in European patent applications, it is important to consider carefully if they are indeed the best way to define an invention at the European Patent Office (EPO), and what supporting technical information and/or evidence may be required.

With this in mind, here are some key considerations for using product-by-process claims at the EPO.

Claim interpretation and validity

At the EPO, a claim defining a product in terms of a process of manufacture is construed as a claim to the product as such. Product-by-process claims are therefore useful as they still allow protection to be obtained for the product per se irrespective of how it is made. However, this means it is the product itself that is assessed for patentability. A product-by-process claim is not considered novel merely by the fact that the product is made by a new process. Rather, the modification of the process must result in a new product that is different from known products. Fundamentally, the technical content of the invention must be found in the technical properties imparted to the product by the process.

It is also important to note that product-by-process claims are only allowable at the EPO if it is impossible to define the claimed product other than in terms of a process of manufacture. It is not uncommon for the EPO to raise clarity objections to product-by-process claims and request that the product be defined in terms of its structural characteristics instead. However, if a robust defence can be provided as to why it would be impossible or impractical to define the product other than by the way it is made, it should be possible to overcome such objections.

For example, one area in which product-by-process claims are readily accepted by the EPO is in the field of polymers. It can often be argued that due to the complex and unpredictable polymerisation process, it is not possible to clearly define the chemical structure of the polymer other than with respect to the starting materials from which it is formed. Product-by-process claims can therefore often be the best way to seek protection for new polymers.

Supporting data

Where an invention is defined in terms of a product-by-process claim, the EPO typically shifts the burden of proof to the applicant to demonstrate that a novel manufacturing process results in a new product that is different from products in the prior art. This may be achieved by generating data using various characterisation techniques. For example, spectroscopic techniques could be used to show that the microstructure of the claimed product is distinct from known products. Alternatively, or where such comparison is not possible, a variation in the chemical structure of the products can be substantiated by evidence of a difference in the physical properties of the products. Moreover, data showing the advantageous properties of the new product that are not suggested by the prior art can also be useful in convincing the EPO that the product does not result from an obvious modification of the known product and is thus inventive.

Generating such comparative data can be a stumbling block for applicants, especially for smaller companies with limited experimental resources. However, without this evidence it is likely that only claims directed to the process itself could be maintained. This would provide a narrower scope of protection and may be more difficult for the applicant to enforce subsequently.

Claim language

For the purpose of validity, the EPO does not make any meaningful distinction between claims defining a product as being “obtained by” a process or “obtainable by” the process. However, the choice of which term to use may impact how the claim is construed for the purposes of infringement in certain territories.

For example, there is some case law suggesting that UK courts distinguish between the two terms when considering infringement. In Hospira UK Limited v Genentech Inc., the court followed the EPO’s approach for the purpose of validity – a claim directed to a product obtained by or obtainable by a process is only novel if the process confers some novel attribute to the product. However, the court held that a claim defining a product ‘obtained by’ a process is not infringed by a product obtained by a different process, whereas a claim defining a product ‘obtainable by’ a process is infringed irrespective of the process by which the product is formed, as long as the product has the exact same characteristics that are an inevitable consequences of the claimed process. A claim with ‘obtainable by’ language may therefore offer a broader scope of protection, at least in the UK.

If you would like to discuss the use of product-by-process claims at the EPO, please get in touch with us at gje@gje.com.