Patents: Smith & Nephew Plc v Convatec Technologies Inc.

In "Educating Samuel: No. 1 Added Matter" 4 Nov 2008 I explained what is meant by "added matter." There are not many cases on added matter.   One such was Smith & Nephew Plc v Convatec Technologies Inc[2012] EWHC 1602 (Pat).

The Context
This was an application by Smith & Nephew to revoke Convatec's European Patent (UK) No. 1,343,510 entitled "Light Stabilized Antimicrobial Materials" on various grounds. In the course of the proceedings Convatec conceded that the patent was invalid and applied to amend.  Smith & Nephew objected to the amendments on the ground that they constituted added matter contrary to s.76 (3) of the Patents Act 1977 of the Patents Act 1977. They also argued obviousness and insufficiency.

The Section
S.76 of the Act provides as follows:
"Amendment of applications and patents not to include added matter76.-(1) An application for a patent which -
(a) is made in respect of matter disclosed in an earlier application, or in the specification of a patent which has been granted, and
(b) discloses additional matter, that is, matter extending beyond that disclosed in the earlier application, as filed, or the application for the patent, as filed,
may be filed under section 8(3), 12 or 37(4) above, or as mentioned in section 15(9) above, but shall not be allowed to proceed unless it is amended so as to exclude the additional matter.
(1A) Where, in relation to an application for a patent -
(a) a reference to an earlier relevant application has been filed as mentioned in section 15(1)(c)(ii) above; and
(b) the description filed under section 15(10)(b)(i) above discloses additional matter, that is, matter extending beyond that disclosed in the earlier relevant application,
the application shall not be allowed to proceed unless it is amended so as to exclude the additional matter.
(2) No amendment of an application for a patent shall be allowed under section 15A(6), 18(3) or 19(1) if it results in the application disclosing matter extending beyond that disclosed in the application as filed.
(3) No amendment of the specification of a patent shall be allowed under section 27(1), 73 or 75 if it -
(a) results in the specification disclosing additional matter, or
(b) extends the protection conferred by the patent.
(4) In subsection (1A) above “relevant application” has the meaning given by section 5(5) above."

The Proposed Amendments
The patent was for methods of making a wound dressing which uses silver as an antimicrobial agent and which is photostable. Between paragraphs [6] and [8], His Honour Judge Birss QC described the invention as follows:
6. Wound dressings have advanced over the years and in the 1990s wound dressings were developed which were intended to keep the wound surface moist. One method of achieving this aim was to use materials which formed a gel. One class of gelling wound dressing used alginate materials. Another kind used carboxymethyl cellulose (CMC).
7. Infection is a problem associated with wounds and consequently there is a need to both prevent and treat infection resulting from wounds. Antimicrobial agents can be used topically to achieve this result. A dry wound environment was not conducive to bacterial, fungal or viral growth. However, as gel dressings became more popular the problem of bacterial growth became more apparent. One antimicrobial agent known for many years is silver. Silver has a number of advantages for topical application including low toxicity. However there is a practical problem associated with the use of silver in wound dressings. It is light stability. This sensitivity is well known. For example the light sensitive nature of silver salts was used in photography for many years.
8. The patent relates to a method of preparing a light stabilized antimicrobial material for use in wound dressings and medical devices. Essentially the method is one whereby a wound dressing material can be made which comprises silver as an antimicrobial agent but which is stable in the presence of light."
Convatec proposed to amend claim 1 of the patent as show in red:
"1. A method of preparing a light stabilized antimicrobial material, characterised in that the method comprises the steps of:
(a) preparing a solution comprising an organic solvent and a source of silver in a quantity sufficient to provide a desired silver concentration in said material;
(b) subjecting a material which includes gel-forming fibres containing one or more hydrophilic, amphoteric or anionic polymers to said solution for a time sufficient to incorporate said desired silver concentration into said polymer, wherein said polymer comprises a polysaccharide or modified polysaccharide, a polyvinylpyrrolidone, a polyvinyl alcohol, a polyvinyl ether, a polyurethane, a polyacrylate, a polyacrylamide, collagen, or gelatin or mixtures thereof; and
(c) subjecting said polymer, during or after step (b) to one or more agents selected from the group consisting of ammonium salts, thiosulphates, chlorides and peroxides which facilitate the binding of said silver on said polymer, the agent being present in a concentration between 1% and 25% of the total volume of treatment, which material is substantially photostable upon drying, but which will dissociate to release said silver upon rehydration of said material."
The Case Law
In "Educating Samuel" I referred to two cases, European Central Bank v Document Security Systems Incorporated [2008] EWCA Civ 192 (19 March 2008) [2008] EWCA Civ 192 and Vector Corporation v Glatt Air Techniques Inc  [2008] RPC 10, [2008] Bus LR D101, [2007] EWCA Civ 805. At paragraph [12] of the European Central Bank case, Lord Justice Jacob had said:
"12. Kitchin J summarised the legal principles for the application of this rule in a manner which was not challenged and which we accept is correct:
'[96] The test for added matter was explained by Aldous J in Bonzel v Intervention Ltd [1991] R.P.C. 553 at 574:
'(a) To ascertain through the eyes of the skilled addressee what is disclosed, both explicitly and implicitly in the application.
(b) To do the same in respect of the patent as granted.
(c) To compare the two disclosures and decide whether any subject matter relevant to the invention has been added whether by deletion or addition.
The comparison is strict in the sense that subject matter will be added unless such matter is clearly and unambiguously disclosed in the application either explicitly or implicitly.'
[97] A number of points emerge from this formulation which have a particular bearing on the present case and merit a little elaboration. First, it requires the court to construe both the original application and specification to determine what they disclose. For this purpose the claims form part of the disclosure (s.130(3) of the Act), though clearly not everything which falls within the scope of the claims is necessarily disclosed.
[98] Second, it is the court which must carry out the exercise and it must do so through the eyes of the skilled addressee. Such a person will approach the documents with the benefit of the common general knowledge.
[99] Third, the two disclosures must be compared to see whether any subject matter relevant to the invention has been added. This comparison is a strict one. Subject matter will be added unless it is clearly and unambiguously disclosed in the application as filed.
[100] Fourth, it is appropriate to consider what has been disclosed both expressly and implicitly. Thus the addition of a reference to that which the skilled person would take for granted does not matter: DSM NV's Patent [2001] R.P.C. 25 at [195]-[202]. On the other hand, it is to be emphasised that this is not an obviousness test. A patentee is not permitted to add matter by amendment which would have been obvious to the skilled person from the application.
[101] Fifth, the issue is whether subject matter relevant to the invention has been added. In case G1/93, Advanced Semiconductor Products, the Enlarged Board of Appeal of the EPO stated (at paragraph [9] of its reasons) that the idea underlying Art. 123(2) is that that an applicant should not be allowed to improve his position by adding subject matter not disclosed in the application as filed, which would give him an unwarranted advantage and could be damaging to the legal security of third parties relying on the content of the original application. At paragraph [16] it explained that whether an added feature which limits the scope of protection is contrary to Art 123(2) must be determined from all the circumstances. If it provides a technical contribution to the subject matter of the claimed invention then it would give an unwarranted advantage to the patentee. If, on the other hand, the feature merely excludes protection for part of the subject matter of the claimed invention as covered by the application as filed, the adding of such a feature cannot reasonably be considered to give any unwarranted advantage to the applicant. Nor does it adversely affect the interests of third parties.
[102] Sixth, it is important to avoid hindsight. Care must be taken to consider the disclosure of the application through the eyes of a skilled person who has not seen the amended specification and consequently does not know what he is looking for. This is particularly important where the subject matter is said to be implicitly disclosed in the original specification."
Judge Birss QC noted at paragraph [57] that the passage above focused on comparing the application to the granted patent because it is concerned with added matter as a ground of invalidity. He added that the same approach applies in relation to post grant amendments save that the patent as proposed to be amended must be compared with the application as filed.

In Vector, the other case to which I referred in "Educating Samuel", discussed an objection to amendment known as "intermediate generalization" which can arise when the patentee proposes to delete words from a claim. As the Court of Appeal put it at paragraph [9] of their judgment in that case:
"A particular, and sometimes subtle, form of extended subject matter (what our Act calls "additional matter") is what goes by the jargon term "intermediate generalisation". Pumfrey J described this in Palmaz's European Patents [1999] RPC 47, 71 as follows:
'If the specification discloses distinct sub-classes of the overall inventive concept, then it should be possible to amend down to one or other of those sub-classes, whether or not they are presented as inventively distinct in the specification before amendment. The difficulty comes when it is sought to take features which are only disclosed in a particular context and which are not disclosed as having any inventive significance and introduce them into the claim deprived of that context. This is a process sometimes called 'intermediate generalisation.'"
Finally, Judge Birss QC reminded himself at paragraph [59] that it is important to distinguish between the disclosure of subject matter and the scope of the claim. This point arose in AC Edwards v Acme Signs [1992] RPC 131 and was recently reaffirmed in Gedeon Richter v Bayer Pharma [2012] EWCA Civ 235 (see paragraph 17).

Application of these Principles
Following Bonzel, the judge decided what was disclosed by the application as filed. Next, he considered what would be disclosed by the patent as amended and in that context he addressed Smith & Nephew's specific objection of intermediate generalization. He then made the comparison and concluded at paragraph [99] that there was no added matter:
"The question is whether the amendments give rise to added matter. In step (b) the amended claim refers to 'a material which includes gel-forming fibres containing one or more hydrophilic, amphoteric or anionic polymers … wherein said polymer comprises a polysaccharide (etc.)'. In my judgment all this discloses is a material which has within it gel forming fibres, those gel forming fibres containing within them polymers which satisfy both lists of properties. That is disclosed in the application as filed."

On obviousness the judge directed himself as follows:
101  Section 3 of the 1977 Act provides that an invention shall be taken to involve an inventive step if it is not obvious to a person skilled in the art having regard to any matter which forms part of the state of the art by virtue of s2(2) of the 1977 Act. A structured approach to the assessment of obviousness was set out by the Court of Appeal in Windsurfing International Inc v Tabur Marine [1985] RPC 59 and was adjusted somewhat by Jacob LJ in Pozzoli v BDMO [2007] EWCA Civ 588, [2007] FSR 37. It is:
(1) (a) Identify the notional 'person skilled in the art';
(b) Identify the relevant common general knowledge of that person;
(2) Identify the inventive concept of the claim in question or if that cannot readily be done, construe it;
(3) Identify what, if any, differences exist between the matter cited as forming part of the "state of the art" and the inventive concept of the claim or the claim as construed;
(4) Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?
102  In Conor v Angiotech [2008] UKHL 49, [2008] RPC 28 the House of Lords considered the issue of obviousness. There Lord Hoffmann (with whom the others of their lordships agreed) approved the following statement of Kitchin J made in Generics v Lundbeck [2007] RPC 32:
'The question of obviousness must be considered on the facts of each case. The court must consider the weight to be attached to any particular factor in the light of all the relevant circumstances. These may include such matters as the motive to find a solution to the problem the patent addresses, the number and extent of the possible avenues of research, the effort involved in pursuing them and the expectation of success.'
103. Since Kreidl was published in 1946 and the patent in this case was filed in 2001, the question of the age of a piece of prior art arises. In the joint judgment of Kitchin LJ and Sir Robin Jacob given inGedeon Richter v Bayer (supra) at paragraph 61, their lordships observed that it was trite law that dates matter when considering obviousness and that the older a piece of prior art said to render a patent obvious, the harder it is to show obviousness. I understand their lordships to mean that the point of law is that dates matter. The observation about it being harder to show obviousness over an old citation is a reflection of long experience in patent cases and common sense. It is not a legal principle. Mr Mellor reminded me of the fuller analysis of this point in Brugger v Medicaid [1996] RPC 635 at 653-655. He also reminded me of the conclusion on this point in Terrell (17th Ed.) which attempts to sum up Brugger as follows "In short there may be many reasons why something was not done before, and one cannot simply conclude that everything that is not anticipated is not obvious". I will bear this in mind."
Earlier in his judgment. Judge Birss QC has identified the skilled addressee and such persons common general knowledge. He summarized the inventive concept at paragraph [105]
"as teaching that if the skilled person follows the steps of the method as claimed fairly the result will be a product which satisfies these criteria. By "fairly" I mean the skilled person has to approach the matter with a will to make it work. The significance of this is that it means that if it is obvious to employ conditions which fall within the method steps with a view to making a light stable antimicrobial dressing, the claim will be invalid. There is no need to go on and separately consider whether those steps would in fact produce a photostable dressing because the patent's teaching is that that is what will happen."
He then compared the claims as amended to two earlier patents relied upon by Smith & Nephew and found that the patent as amended would involve an inventive step and would thus be valid.

The judge dealt with this point shortly between paragraphs [198] and [201]:

"Smith & Nephew's pleaded case is:
[Gibbins] discloses light stabilized antimicrobial materials which turn a purple (or purplish) colour, discolouring more quickly particularly at higher concentrations of silver. To the extent that such materials disclosed in [Gibbins] are said not be "substantially photostable" within the meaning of the Patent, then the Patent does not describe (a) what this requirement means; (b) how a skilled person knows whether or not a particular method meets this requirement and/or (c) how the method is to be performed in order to achieve a result which meets this requirement.
199. Smith & Nephew referred to Prof Kennedy's view that a material which had purple specks when dry would not fall within the definition in the patent. It argued that if a material that is purple with specks when dry, i.e. at the end of the manufacturing process, is not a material which has undergone a controlled colour change within the meaning of the patent then the patent must be insufficient. I do not have to resolve that question because I have found that Example 24 (the material that is purple with specks when dry) is within the claim.
200 The fact that I am not satisfied that as written, Gibbins discloses that all the samples in Example 25 were photostable materials within claim 1, has no bearing on insufficiency. It does not show any ambiguity about the definition.
 201  There is nothing before me to suggest that the skilled person would not know what "substantially photostable" in the patent means. Nor is there anything to suggest that the skilled person would have difficulty knowing whether any given method fell within the claim or determining how to perform a method in a way which meets the criterion. I reject the insufficiency argument."
The judge concluded that the patent as amended would be valid and allowed those amendments. In this note, I have not gone into any detail on the facts or specific points of construction because it would have made this already long post even longer. I have therefore concentrated on the points of law which are not exactly easy in themselves.  I am conscious that there are many points which may require amplification or clarification. If anyone wants to discuss this case with me - or indeed the concepts of added matter, obviousness or insufficiency - he or she should call me on 0800 862 0055 or contact me through Facebook, Linkedin, twitter or Xing, or through my contact page.


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