Coloplast v Salts

Coloplast A/S v Salts Healthcare Limited [2021] EWHC 3 (Pat) (18 January 2021)


First published in EPLAW Patent Blog, January 2021.

In this judgment Nicholas Caddick QC, sitting as a Deputy High Court Judge, found Coloplast’s patent for a “comfort layer” for an ostomy bag invalid for obviousness over the common general knowledge and also over five separate prior art citations. The lengthy judgment also deals with Coloplast’s claim that Salts’ “Confidence BE” range of ostomy bags infringes the patent as well as Salts’ rejected claims for (i) lack of novelty; (ii) AgrEvo obviousness; (iv) insufficiency; and (v) added matter.


Coloplast A/S (“Coloplast”) is the proprietor of European Patent (UK) 2 854 723 (“EP 723”) entitled “Comfort layer for a collecting bag”. Salts launched a range of ostomy bags (the “Confidence BE” range) around November 2017 and, in April 2019, Coloplast initiated proceedings against Salts for infringement of EP 723. Salts disputed infringement and counterclaimed for invalidity of the patent.

Skilled Person and Common General Knowledge (“CGK”)

Ostomy bags are used to collect body waste that is discharged through an ostomy or stoma (a surgically created opening in the lower intestine or urinary tract). The Deputy Judge held that the relevant skilled person had a practical interest in the design of such bags including knowledge of the manufacturing processes and materials used for such bags.

For functional reasons ostomy bags must be made of an impermeable material (the barrier layer). However, if this layer is in direct contact with the patient’s skin it may cause discomfort due to condensation or perspiration and it may also make an undesirable rustling noise. A “comfort layer” is therefore added to the ostomy bag of the patent in order to reduce this moisture and noise, thereby improving comfort and dignity for the patient. Comfort layers were not a new concept at the priority date of EP 723 thus it was the particular characteristics of the Coloplast comfort layer that were claimed to be inventive.

Claimed invention of EP 723 and assessment of obviousness

As set out by the Deputy Judge, Coloplast claimed that its Patent “for the first time teaches that a woven fabric can be used and welded in such a way to form an integrated comfort layer with improved properties”. More specifically, the inventive concept claimed by Coloplast was to a woven comfort layer that was integrated to the barrier layer (i.e. not a separate removal cover) by a sufficiently strong joining method and where the area of the comfort layer that was joined to the barrier layer maintained a tactile and visual similarity to the area which was not joined. To achieve this EP 723 taught that, at the join between the layers, the fibres of the woven comfort layer were embedded within the barrier layer to achieve the necessary strength but not so much as to make the join hard and visually dissimilar to the rest of the comfort layer.

The Deputy Judge considered the CGK and concluded that non-integrated (i.e. removable) woven comfort layers were well known at the priority date of May 2012 as were integrated comfort layers made of non-woven material. Evidence from Salts’ own expert witness was that integrated comfort layers made of woven material had not been produced by the priority date (essentially conceding that EP 723 was novel) but that the possibility of using woven fabric for integrated cover was in the mind of the skilled person at the priority date. The Deputy Judge held that this avenue had not been pursued due to the additional cost of woven materials and environmental disadvantages of using them. This finding was key to the resolution of the issues in dispute.

When considering obviousness, the Deputy Judge emphasised the importance of the “inventive step” by quoting Jacob LJ’s example that a 5 ¼ inch plate may be novel and not an obvious size of plate, but it cannot be patented as it involves no inventive step from known examples of plates (Actavis UK Limited v Novartis AG [2010] EWCA Civ 82). Furthermore, it was important not to confuse commercial factors with technical obstacles when assessing obviousness/inventive step (Laddie J in Brugger v Medic-Aid Ltd [1996] R.P.C. 635).

With these principles in mind the Deputy Judge concluded that EP 723 merely disclosed commonly known techniques for making an ostomy bag with an integrated woven comfort layer. There was no inventive step either from the CGK or from the prior art cited. In particular, the characteristics of the comfort layer claimed in EP 723 (the strength of the join and the tactile and visual characteristics) were not achieved by overcoming any technical obstacles but were a natural consequence of using the commonly known methods of manufacture. The reason such comfort layers had not been made before was simply due to commercial factors.


The Deputy Judge noted (following the Supreme Court’s decision in Regeneron v Kymab [2020] UKSC 27 at [56]) that the disclosure of the patent when coupled with the CGK must be sufficient to enable the skilled person to work the claimed invention. The Deputy Judge then said “In my judgment the Patent did not involve an inventive step because it was well known that a woven could be used in such a way as to achieve claims 1 to 4, and because the means of achieving the requirements of claims 1 to 4 involved using materials and techniques that were part of the common general knowledge. The corollary of this must be that the disclosure of the Patent was not insufficient” (emphasis added)

Salts also argued that use in EP 723 of the language “having the same tactile characteristics” and “having the same visual characteristics” in claims 3 and 4 was uncertain such that the skilled person could not know if a product fell within either of these claims. In dismissing this argument, the Deputy Judge drew a parallel with the language used in the Registered Designs Act 1949 and the Trade Marks Act 1994, which he thought was no less clear (e.g. the Trade Marks Act uses the language “Whether the mark is identical or similar to another mark”) and which formed part of statutory tests.

AgrEvo obviousness

Counsel for Salts noted that AgrEvo obviousness occurs at the boundary of obviousness and insufficiency. In particular, as the Deputy Judge summarised the law, it is an assessment of whether the technical effect or advantage claimed by a patent can plausibly be said to apply to the breadth of the embodiments claimed. Salts argued that EP 723 failed in this regard since the characteristics claimed as advantages in the patent are “not something that all wovens offer”. However, the Deputy Judge rejected this. In his view the claims themselves put a constraint on the wovens which EP 723 teaches to use. In other words, EP 723 did not claim all woven materials, it only claimed those with the characteristics of the claims.

Added Matter

Salts’ case on added matter revolved around the language used in relation to the way in which fibres of the woven comfort layer were embedded in the barrier layer at the join. The Application referred to “not all” fibres being embedded in the barrier but the Patent used the phrase “some, but not all”. Salts alleged this change constituted added matter but the Deputy Judge disagreed, holding that by substituting the words “some, but not all” for the words “not all” , the patentee was simply using different words to describe the same result. No new technical matter had been added by the change in language.

Infringement and conclusion

The Deputy Judge found that (if valid) Salts’ “Comfort BE” product would have infringed EP 723. However, as explained above, he had already found EP 723 invalid for obviousness over both the CGK and the five prior art citations raised by Salts.

A link to the judgment can be found here.

Nicholas Round


Related Articles