Patents: Convatec Ltd. v Smith & Nephew Healthcare Ltd

In Convatec Ltd. and others v Smith & Nephew Healthcare Ltd and Others [2011] EWHC 2039 (Pat) (27 July 2011), His Honour Judge Birss QC, sitting as a judge of the High Court, tried a claim for patent infringement and a counterclaim for revocation of the patent in suit on the grounds of anticipation, obviousness and insufficiency.

The invention for which the patent was granted was a moist wound dressing. The patent specification explained that most dressings consisted of materials that tended to absorb puss and other body fluids produced by a wound known as exudate. Such absorption tended to dry and thereby stick to the wound thus impeding healing. The invention was a gel that kept the wound moist while absorbing exudate.

The relevant claims were as follows:

"Claim 1:

A wound dressing comprising a blend of discrete modified cellulose gel forming fibres with at least one other type of discrete gel forming fibres.

Claim 3:

A wound dressing as claimed in any preceding claim wherein the dressing comprises a wound contacting surface consisting of a blend of discrete modified cellulose fibres with at least one other type of discrete gel forming fibres.

Claim 5:

A wound dressing as claimed in any preceding claim wherein the dressing comprises a blend of discrete alginate fibres and discrete modified cellulose fibres.

Claim 9:

A wound dressing as claimed in any preceding claim wherein the gel forming fibres have an absorbency of at least 2 g of liquid per g of fibre."

The first case I used to get my pupils to read thge first occasion a patent infringement case came into chambers during their pupillage was Nobel's Explosive Co. Ltd. v Anderson (1894) 11 RPC 519. The reason I did that was that it sets out the methodology for deciding whether a patent has been infringed. At page 522 the Master of the Rolls said:

"Now as to the law of the case, - Here is a patent, and an alleged infringement. What is the course that the Court ought to take? In my opinion it is perfectly plain that the first thing that the Court must do is to construe the Specification. How can you consider at all the question whether what is alleged is an infringement of the patent until you have made up your mind what is the true construction of the Specification."

The next question that his lordship addressed was when the specification should be construed. He continued on the next page:

"

Now what is the very first canon of construction of all written business documents? Why, that the Court ought to construe them the day after they were published. That is the first. Therefore in construing this patent, one has no right to do what Mr Moulton so often invited us to do, by considering what the Defendant has done. I adjure that altogether, and I say we are bound to construe the patent as if we had to construe it before the Defendant was born, if the patent was before that time."

That rule remains as true today as it did then and it is noteworthy and commendable that Judge Birss QC referred to that case at paragraph [68] of his judgment. The reason he did that was that in construing the first of the above claims upon which all the subsequent claims depended he rejected the constructions of both parties' counsel and substituted his own.

Not having been present in court and not having read the skeletons I have to be careful not to do a disservice to my friends on both sides but it seems to me that they spent an awful lot of time exploring blind alleys. For example, there appears to have been a lot of argument over whether the words

"A wound dressing comprising a blend of discrete modified cellulose gel forming fibres with at least one other type of discrete gel forming fibres"

claimed a product or merely a product by process (that is to say, a product derived from a process). Being, as Baroness Kennedy QC once put it, "a puir woman" also from Borealian regions the answer seems to me to have been obvious and so it transpired. With admirable clarity, Judge Birss QC concluded at paragraph [77]:

"Claim 1 is a product claim. It requires the wound dressing to comprise a mixture of two classes of gel forming fibre. The mixture must be intimate but the fibres must retain their separate (discrete) nature. There must be modified cellulose gel forming fibres together with at least one other type of gel forming fibres, i.e. some gel forming fibres not made of modified cellulose."

In cases such as this that turn on the construction of the specification and their own facts there is not much point in going into the details. Counsel for the claimant concluded that claim 1 had been anticipated and the judge found that even if it had been valid it would not have been infringed. He found that the remaining claims to have been valid rejecting the obviousness and insufficiency attacks. Having found claim 1 not to have been infringed he made similar findings in relation to the remaining claims.

It is perhaps worth quoting from the passages that show the judge's reasoning. As to infringement he said at paragraph [48] of his judgment:

"In Kirin Amgen Inc v Hoechst Marion Roussel [2004] UKHL 46, [2005] RPC 9 the House of Lords comprehensively reviewed the principles applicable to patent construction under the 1977 Act bearing in mind Article 69 of the European Patent Convention and the Protocol on the Interpretation of Article 69. Construction of a patent claim is purposive in nature and the question is always to work out what the person skilled in the art would have understood the patentee to be using the language of the claim to mean. Lord Hoffmann put it this way in paragraph 34:

'34. "Purposive construction" does not mean that one is extending or going beyond the definition of the technical matter for which the patentee seeks protection in the claims. The question is always what the person skilled in the art would have understood the patentee to be using the language of the claim to mean. And for this purpose, the language he has chosen is usually of critical importance. The conventions of word meaning and syntax enable us to express our meanings with great accuracy and subtlety and the skilled man will ordinarily assume that the patentee has chosen his language accordingly. As a number of judges have pointed out, the specification is a unilateral document in words of the patentee's own choosing. Furthermore, the words will usually have been chosen upon skilled advice. The specification is not a document inter rusticos for which broad allowances must be made. On the other hand, it must be recognised that the patentee is trying to describe something which, at any rate in his opinion, is new; which has not existed before and of which there may be no generally accepted definition. There will be occasions upon which it will be obvious to the skilled man that the patentee must in some respect have departed from conventional use of language or included in his description of the invention some element which he did not mean to be essential. But one would not expect that to happen very often.'

A number of points emerge from this passage which are of particular relevance to these proceedings. First, the words of the claim are to be construed having regard to the patentee's purpose as set out in the rest of the specification. Second, the exercise is one of interpretation of the words of the claim. It follows that it is not permissible simply to ignore an integer of the claim; nor is it permissible to write a new integer into the claim."

He also referred to the following passage from Lord Justice Jacob's judgment in Virgin Atlantic Airways Ltd v Premium Aircraft Interiors UK Ltd [2009] EWCA Civ 1062 [2010] RPC 8 at paragraph [5]:

"One might have thought there was nothing more to say on this topic after Kirin-Amgen v Hoechst Marion Roussel [2005] RPC 9. The judge accurately set out the position, save that he used the old language of Art 69 EPC rather than that of the EPC 2000, a Convention now in force. The new language omits the terms of from Art. 69. No one suggested the amendment changes the meaning. We set out what the judge said, but using the language of the EPC 2000:

[182] The task for the court is to determine what the person skilled in the art would have understood the patentee to have been using the language of the claim to mean. The principles were summarised by Jacob LJ in Mayne Pharma v Pharmacia Italia [2005] EWCA Civ 137 and refined by Pumfrey J in Halliburton v Smith International [2005] EWHC 1623 (Pat)following their general approval by the House of Lords in Kirin-Amgen v Hoechst Marion Roussel [2005] RPC 9. An abbreviated version of them is as follows:

(i) The first overarching principle is that contained in Article 69 of the European Patent Convention;

(ii) Article 69 says that the extent of protection is determined by the claims. It goes on to say that the description and drawings shall be used to interpret the claims. In short the claims are to be construed in context.

(iii) It follows that the claims are to be construed purposively—the inventor's purpose being ascertained from the description and drawings.

(iv) It further follows that the claims must not be construed as if they stood alone—the drawings and description only being used to resolve any ambiguity. Purpose is vital to the construction of claims.

(v) When ascertaining the inventor's purpose, it must be remembered that he may have several purposes depending on the level of generality of his invention. Typically, for instance, an inventor may have one, generally more than one, specific embodiment as well as a generalised concept. But there is no presumption that the patentee necessarily intended the widest possible meaning consistent with his purpose be given to the words that he used: purpose and meaning are different.

(vi) Thus purpose is not the be-all and end-all. One is still at the end of the day concerned with the meaning of the language used. Hence the other extreme of the Protocol—a mere guideline—is also ruled out by Article 69 itself. It is the terms of the claims which delineate the patentee's territory.

(vii) It follows that if the patentee has included what is obviously a deliberate limitation in his claims, it must have a meaning. One cannot disregard obviously intentional elements.

(vii) It also follows that where a patentee has used a word or phrase which, acontextually, might have a particular meaning (narrow or wide) it does not necessarily have that meaning in context.

(vii) It further follows that there is no general "doctrine of equivalents."

(viii) On the other hand purposive construction can lead to the conclusion that a technically trivial or minor difference between an element of a claim and the corresponding element of the alleged infringement nonetheless falls within the meaning of the element when read purposively. This is not because there is a doctrine of equivalents: it is because that is the fair way to read the claim in context.

(ix) Finally purposive construction leads one to eschew the kind of meticulous verbal analysis which lawyers are too often tempted by their training to indulge."

Finally the judge reminded himself a paragraph [50] of his judgment that "it is always important to bear in mind that the skilled person reads the specification in light of the common general knowledge and appreciating that its purpose is to describe and demarcate an invention, that is to say a practical idea for a new product or process."
As to obviousness, the judge directed himself as follows at paragraphs [125] and [126]

"125. 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?

126. 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."

This is a useful little case for a law student or novice intellectual property practitioner because it really has everything in it. If anyone wants to read another view of this case, I can commend the post of my friend Peter Groves on the case of 27 July 2011 in his Ipso Jure blog.