Designs and patents: commercial success

By Audrey Horton


The High Court has held that patents and designs for a medical device were valid and either infringed or would be infringed by competing devices.


A patent is invalid for lack of inventive step if the invention claimed in it was obvious to a person skilled in the art having regard to the state of the art at the priority date (section 3, Patents Act 1977). 

When considering obviousness in relation to commercial success, the court should consider:

How well the patentee's development has been received commercially.

The extent that it can be shown that the whole or much of the commercial success is due to the technical merits of the development, that is, that it solves a problem (Schlumberger Holdings Ltd v Electromagnetic Geoservices AS [2010] EWCA Civ 819).

Registered Community designs (RCDs) must be new and have individual character (Article 4(1), Community Designs Regulation (6/2002/EC)) (the Regulation). Individual character means that the overall impression it produces on the informed user differs from the overall impression produced on an informed user by any design which has been made available to the public before the filing or priority date of the design for which protection is sought (Article 6, the Regulation). When assessing individual character, the degree of freedom of the designer in developing the design is taken into consideration (Article 6(2)). 

The scope of the protection conferred by a Community design includes any design which does not produce on the informed user a different overall impression (Article 10(1), the Regulation). In assessing the scope of protection, the degree of freedom of the designer in developing his design will be taken into consideration (Article 10(2), the Regulation). 

The UK unregistered design right protects designs of the shape or configuration of the whole or part of an article against copying (section 213, Copyright, Patents and Designs Act 1988).


A developed a medical device used with colonoscopies, the Endocuff, which was protected in the UK by patents, two RCDs and UK unregistered design rights. Initially, the Endocuff was distributed in the US by C under an agreement. 

C then developed its own cuff called AmplifEYE and began to distribute it, including in the UK, after the agreement expired. 

C brought an action to revoke the patents and a declaration of non-infringement of the RCDs in relation to the AmplifEYE and two proposed new versions of the AmplifEYE. A counterclaimed for infringement of its rights and applied to amend the patents.


The court allowed A to amend the patents. It held that the amended patents were valid and infringed by both the existing and proposed designs of C's cuff. 

If no commercial value was attached to the solution up to the priority date, the fact that the problem was not solved earlier said little about whether it was obvious. Here, there was no evidence directly addressing the commercial appreciation of those in the industry at the priority date regarding the technical development claimed in the patent. But the fact of litigation suggested that the parties now believed that A's claimed invention had commercial value. The evidence as a whole showed that at the priority date those in the industry would have believed that a device which improved visualisation would be of potential commercial value.

A plea of commercial success would rarely be more persuasive in establishing inventive step than considering obviousness without reference to commercial success. Secondary evidence, and primary evidence on inventive step, works by inference. An inference drawn from commercial success enjoyed some time after the priority date would be very remote.

Here, the relevant secondary evidence was that those in the industry most likely to think of the invention at the priority date were the three main suppliers of colonoscopes, with large well-funded research departments. One of them was responsible for all three items of prior art although none led to a product on the market. A's argument was that as none of the industry giants thought of the invention, nor would the skilled team have done so. C's argument that, absent knowledge of the commercial policy of other companies in the relevant industry, secondary evidence of this kind was valueless was contrary to Schlumberger. As anything that improved use of its colonoscopes would have been of interest to the other companies, they were unlikely to ignore an obvious route to better visualisation. 

The secondary evidence was persuasive. It is likely that, if the product claimed in the patents had been obvious to the skilled team at the priority date, it would have been likewise obvious to the relevant research teams at the major colonoscope producers. One of them would then likely have developed a product along the lines of the Endocuff. On the balance of probabilities, the secondary evidence supported A’s case that there was an inventive step.

Both RCDs were valid, but one was not infringed and the other was infringed by AmplifEYE but not by the alternative versions of it, which would produce a different overall impression on the informed user.

The UK unregistered design rights would be infringed from the date of the judgment by all the designs. The argument that the designs relied on consisted of features that enabled the articles to be placed in or against the colon wall so that they might perform their function and that therefore the "must fit" exception to the subsistence of design right was rejected as it applied only where there was a sufficient degree of precision in the fit between the articles. That was not the case between an Endocuff design and the wall of a colon.

The evidence showed that C had copied the Endocuff in the course of creating the design for the AmplifEYE, which was substantially to the design of both. Also, the differences between the AmplifEYE and its alternative versions were insufficient to prevent the latter from being substantially to the design of the Endocuff, given the chain of copying and the similarities that existed. Only secondary infringement was in issue. C did not have the requisite knowledge or reason to believe that the AmplifEYE products were infringing articles, except from the date of the judgment. 


The court's comments on the value of a plea of commercial success tend to support the commonly held view that this plea is generally so difficult to establish that it is rarely worth raising in defence of inventive step. However, other issues of secondary evidence should always be carefully considered: here, they were the deciding issues in the determination that the claims were not obvious. The decision is also an interesting example of a medical device protected both by patent and registered/unregistered designs.

Case: Cantel Medical (UK) Ltd and another v ARC Medical Design Ltd [2018] EWHC 345 (Pat).

First published in the April 2018  issue of PLC Magazine and reproduced with the kind permission of the publishers.  Subscription enquiries 020 7202 1200.