Patents Court finds no infringement of ostomy bag patent, even under doctrine of equivalents test

Summary

In the recent case of Salts Healthcare Ltd v Pelican Healthcare Ltd [2025] EWHC 497 (Pat), the Patents Court assessed the validity of a patent for an ostomy appliance and considered whether a rival company’s ostomy bag infringed on either a normal construction or by equivalents. 

Background

Salts Healthcare (“Salts”), proprietor of UK Patent GB 2 569 212 concerning ostomy appliances (the “Patent”), brought a claim against Pelican Healthcare (“Pelican”), seller of the “ModaVi” ostomy bag. Salts alleged that the ModaVi infringed claims 5, 8, and 20 of the Patent, both on a normal interpretation and under the doctrine of equivalents. Pelican denied infringement and alleged that the Patent was invalid due to lack of novelty, inventive step, and added matter. Salts also applied to conditionally amend the Patent. 

The Patent / Claims 

The ostomy bags described in the Patent have front and back walls connected by a weld at or near their peripheries. Each of the claims alleged to be infringed required a “weld portion” which “extends away from a periphery of the appliance… downwardly towards a bottom of the appliance”. Claim 5 required four weld portions, claim 8 required two and claim 20 required a plurality of weld portions.

Mr Ian Karet (sitting as a judge of the Chancery Division), interpreted “weld portion” to be “a weld that connects the front of the bag to the back.” The requirement that the weld “extends away from a periphery of the appliance” means it is part of or additional to the peripheral connection. Regarding the weld portion extending “downwardly towards a bottom of the appliance”, the judge rejected Salts’ argument that this would include the bag changing direction to direct waste downwards. He instead held that this meant that the weld points down towards the bottom of the bag.

Infringement 

Salts alleged that the ModaVi closed form (a one-use ostomy bag that is thrown away once filled) infringed claims 5, 8 and 20 (when dependent on claims 8, 18 and 19) and the ModaVi drainable form (which allows emptying and re-use) infringed claim 8. Salts relied on a range of evidence of infringement, including a product and process description, publications by Pelican and experiments.

The alleged infringing elements of the ModaVi bag were the ‘waist’ and ‘lobes’. The waist is the point at which the width of the bag tapers inwards. The lobes are thicker sections of the peripheral weld extending inwardly from the lower edge. 

As a first step the judge considered the inventive concept of the Patent. He held this to be: “an ostomy appliance that has weld portions additional to the periphery of the appliance which are placed so as to minimise bulging outwards or downwards or pulling at the wafer as the bag fills in use. The welds are additional to the periphery.”

The judge found that there was no infringement on a normal, purposive construction. The waist was not a weld portion as it did not extend away from the periphery of the ModaVi bag, nor did it extend downwards. While the judge agreed that the lobes extended away from the periphery, he did not accept that they extended downwards. 

1. On infringement by equivalents, the judge considered the three questions from Actavis v Lily [2017] UKSC 48: The first question was whether the lobes and waist portions of the ModaVi bag achieved substantially the same result in substantially the same way as the inventive concept of the Patent. In respect of the waist of the ModaVi bag, the answer to the first Actavis question was ‘no’ as the waist does not achieve the result by limiting the space within the periphery available to fill with waste. However, in relation to the lobes, the first Actavis question was ‘yes’ as the lobes affect the shape of the bag so as to minimise bulging outwards or downwards, or pulling at the wafer as the bag fills in use. 
2. The second question was whether it would be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention. The answer to this was ‘yes’.
3. The third question was whether such a reader of the patent would have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention. For the bag as a whole, the answer to this was ‘yes’. The invention could be achieved in a number of ways. Salts had chosen a particular way to achieve the intended effect and had limited the claims to specific structures. Salts could have formulated a claim by result or to a ‘narrower’ bag or to omit the word ‘downwardly’, but did not do that. The judge concluded that strict compliance was intended, and consequently there was no infringement by equivalence. 

Validity 

A prior art citation, Grum-Schwensen, which disclosed a drainable ostomy pouch including “inwardly protruding welding portions”, was found to anticipate claim 8 of the Patent. The judge held that the weld portions were additional to the periphery of the bag and extended away from the periphery and downwardly toward the bottom of the bag. Claims 5 and 20 were not anticipated as the disclosure was of a single set of weld portions, and it was not obvious to add a second set of welds. 

The judge considered that the Patent was non-obvious over the other prior art citations:-

1. It was not obvious to add weld portions to the waisted bag disclosed in Falconer. 
2. Hannan addressed the problem of overfilling with liquid at the top of the bag so was significantly different to the inventive concept of the Patent. 
3. The bag with spot welds disclosed in Wheaton did not minimise bulging outwards or downwards or pulling at the wafer as the bag fills. 

In relation to added matter, Pelican claimed that the only support for claim 5 was claim 28 as filed, which relates to “an ostomy appliance”, whereas claim 5 of the Patent is limited to a “colostomy or ileostomy” appliance. Salts argued that the skilled person would understand that an ostomy appliance could generally be a urostomy, ileostomy or colostomy appliance. The judge dismissed the attack, holding that the options disclosed in the application are present in the Patent and the form of claim 5 was not objectionable. 

Salts were permitted to amend claim 8 to a “closed colostomy appliance”. 
This amendment had no impact on the assessment of infringement. 

Comment

This case is a good illustration of how the Actavis questions will be applied to an assessment of infringement by equivalence. Even if the first question answered in the affirmative, there may not be infringement if strict compliance with the literal meaning of the claim was intended.