Defining a medical device as a product-by-process (T 1869/19)

The decision in T 1869/19 relates to the patentability of a medical device defined in a patent according to its method of manufacture, in the form of a "product-by-process" claim. The decision highlights the difficulty and limitations of the product-by-process claim format, and raises questions as to the value to innovators of this type of claim format. 

Legal background: Patenting medical devices

Medical devices are difficult candidates for patent protection. Pharmaceutical innovators are rewarded for investment in finding new therapeutic uses for known compounds by the availability of patent protection for new medical use (Article 54(4) and (5) EPC). The Enlarged Board of Appeal (EBA) has, however, specifically ruled out the availability of patent protection for the new use of a known device (although the Boards of Appeal have struggled to satisfactorily define the difference between a "substance or composition" and "a device" (IPKat)). 

An eye to the process

Whilst second medical use claim format is not available for medical devices, a medical device can instead be defined by a new method of manufacture in form of a "product-by-process" claim. In order for the process features of such a claim to confer novelty, the process must cause the claimed product to have different properties to products known from the prior art (T 150/82). This can be a difficult hurdle to jump, often necessitating very narrow restriction of the claimed subject matter to the particular parameters of the process steps. 

T 1869/19: Defining the process of manufacture

The patent EP2329811 in question in T 1869/19 claimed an implant device for the eye. The implant was defined by both product and process features. All of the product features specified by the claim were disclosed in the prior art. The process for producing the implant, on the other hand, included two extrusion steps that were not described in the prior art. The Opposition Division revoked the patent for lacking novelty in view of known products in the prior art. 

The patentee argued on appeal that the extrusions steps specified in the claim caused the resulting implants to have a higher density and less brittleness than the simpler extrusion steps used to make the prior art implants. However, the Board of Appeal was not convinced that the process defined in the claim was described in sufficient detail to necessarily confer the highlighted novel properties of the device. For the Board of Appeal, the claimed product-by-process was too broadly defined and covered implants that were not necessarily indistinguishable from the prior art implants. The Board of Appeal therefore rejected the appeal and upheld the Opposition Division decision that the claims lacked novelty. 

Final thoughts

The availability of product-by-process claims in Europe permits the patenting of medical devices according to their method of manufacture. However, the use of product-by-process claims has two downsides. First, it is difficult to achieve broad protection with product-by-process claims. The EPO will require applicants to demonstrate a causal link between process steps and the properties of the resultant device. Applicants will therefore often be forced to limit the claims to the very specific parameters used in the exemplified process described in the specification. 

Second, even if a product-by-process claim for a medical device is achieved, the enforceability of such a claim represents a challenge in and of itself (Hospira v Genentech ([2014] EWHC 3857, IPKat)). In particular, the patentee must demonstrate that the alleged infringing product has in fact been obtained by the claim process, not just that it could have been obtained by the claimed process. In a world where many manufacturing processes are closely guarded trade secrets, proving infringement of a product-by-process claim is thus easier said than done. 

Further reading

Hurray for judicial sense on product by process claims - Birss triumphs in Hospira v Genentech (10 Dec 2014)

Reference to a hybridoma does not limit a product-by-process antibody claim (T 0032/17) (1 Jun 2021)

Substance or device - a distinction without a difference? (18 Dec 2018)