BASF AG v Smithkline Beecham Plc

In his judgment of 12th July 2002 ([2002] EWCH 1373 (CH)), Pumfrey J held that claims 1, 2, 3, 7, 10(ii), 12 and 13 of UK Patent GB 2, 297, 550 (the patent) invalid and claims 10(i) and 11 valid. Against the judge’s order SmithKline Beecham Plc (SB), the patentees, appeal. BASF AG cross-appeal contending that the judge should also have held claims 10(i) and 11 valid.

SB have not attempted to overturn the judge’s conclusion that claims 1, 2, and 6 and the second alternative in claim 10 (claim 10(ii)) were invalid. Their appeal essentially turns upon a question of construction, in particular the meaning of the phrase “substantially free of bound propan-2-ol” which appears in claim 3. If that phrase has the meaning for which SB contend then, upon the findings of the judge, claim 3 and its dependent claims would be valid.

BASF support the judge’s conclusion on construction. They also contend that claims 10(i) and 11 should have been held to be anticipated by the disclosure in UK patent application no. 8526407, referred to for convenience as 407, or was obvious in the light of that disclosure.

Construction – It is convenient at the outset to set out the issue. The relevant claims showing, underlined or deleted, the amendments allowed on 17th April 2001 are in this form:

“1.

Paroxetine hydrochloride anhydrate substantially free of bound propan-2-ol.

1.

2. Paroxetine hydrochloride anhydrate substantially free of bound organic solvent.

2.

3. Paroxetine hydrochloride anhydrate substantially free of bound propan-2-ol with the proviso that it is other than Form Z.

…

3.

8. Paroxetine hydrochloride anhydrate substantially free of bound propan-2-ol as defined in claim 1 in Form A; which is characterised in that …

4.

9. Paroxetine hydrochloride anhydrate substantially free of bound propan-2-ol as defined in claim 1 in Form B; which is characterised in that …

5.

10. Paroxetine hydrochloride anhydrate substantially free of bound propan-2-ol as defined in claim 1 in Form C; which is characterised in that …

6.

11. Paroxetine hydrochloride anhydrate substantially free of bound propan-2-ol as defined in claim 1 in Form D which is characterised in that …

7.

12. Paroxetine hydrochloride anhydrate as defined in claim 3 8, which is in the form of needles.

8.

13. Paroxetine hydrochloride anhydrate as defined in claim 4 9, which is in the form of needles.

9.

14. Paroxetine hydrochloride anhydrate as defined in claim 5 10, which is in the form of needles or prisms.

…

10.

16. A process for the preparation of paroxetine hydrochloride anhydrate substantially free of bound propan-2-ol which comprises crystallising paroxetine hydrochloride in either:

(i)

an organic solvent or mixture of organic solvents which form a solvate with the paroxetine hydrochloride and which are not removable by conventional vacuum oven drying techniques; or

(ii)

an organic solvent or mixture or organic solvents which do or do not form a solvate with the paroxetine hydrochloride but which are removable by conventional vacuum oven drying;

thereafter in the case of (i) displacing the solvated solvent or solvents using a displacing agent and in the case of (ii) by removing the solvent.

11.

18. A process for the preparation of paroxetine hydrochloride anhydrate substantially free of bound organic solvent which comprises displacing the solvated solvent or solvents from a paroxetine hydrochloride solvate using a displacing agent.

12.

19. A pharmaceutical composition comprising a compound as claimed in any one of claims 1-9 3 or 7-15 and a pharmaceutically acceptable carrier.

13.

20. The use of a compound as claimed in any one of claims 1-9 3 or 7-15 in the manufacture of a medicament for the treatment and/or prevention of the Disorders as defined herein.”

The reasons for the amendment are clear. SB decided that it was appropriate to delete claim 1. As old claims 8, 9, 10 and 11 were either directly or indirectly dependent on claim 1, it was necessary to add into those claims the limitation in claim 1 “substantially free of bound propan-2-ol”. Thus the ambits of those claims were the same after amendment as before.

The importance of the phrase “substantially free of bound propan-2-ol” arises out of an allegation that claim 3 and its dependent claims lacked novelty. BASF relied upon an experiment in 407 in which the anhydrate was produced using acetone as the solvent. Propan-2-ol was never used. The result was Form A. As that experiment did not use propan-2-ol, it was contended that the phrase was not limiting and therefore claim 3 was anticipated.

The judge, supported by BASF, held that the phrase “substantially free of bound propan-2-ol” as used in claim 3 meant what it said. It followed that claim 3 was anticipated by paroxetine hydrochloride anhydrate (PHA) even though it was not substantially free of the solvent used in preparation, provided it was free of bound propan-2-ol which was not and could not have been present.

SB contend that in context “propan-2-ol” is a synecdoche. It is an example standing for whichever member of the class of solvents that was used in the process of production. Any other construction rendered the specification inconsistent.

Section 125 of the Patents Act 1977 makes it clear that the invention of a patent is to be taken to be that specified in the claims. The claims have to be interpreted with the aid of the description. However the Protocol on the Interpretation of Article 69 of the European Patent Convention applies. That Protocol has been considered in a number of judgments. It is sufficient for the purposes of this case to record that the proper approach is to seek the middle ground between literal construction and treating the claims as guidelines. That quest has to achieve reasonable certainty for the public and fair protection for the patentee.

I did not discern any difference of substance between the parties as to the general principles to be adopted. The difference lay in the application and the result. However Mr Waugh QC, who appeared for SB, submitted that any difficulty of construction should be resolved in favour of the patentee. He relied upon the speech of Lord Davey in Parkinson v Simon [1895] 12 RPC 404 at 411. That submission has been dealt with in full in the judgment of Sedley LJ, with which I agree. I therefore turn to the specification which I will consider taking into account the submissions of the parties.

The issue of construction depends in the main upon the way the opening paragraphs are to be understood against the background of the claims. The specification is headed “Paroxetine Hydrochloride Anhydrate Substantially Free of Bound Organic Solvent”. It then states that the invention relates to novel compounds, to processes for preparing them and to their use in treating medical disorders. It acknowledges that Example 8 of EP-B-223403 (403) was prior art. That example describes the preparation of PHA as platelets melting at 118^oC and with certain IR bands by crystallisation from a water-containing solvent. It continues:

“Subsequent repetition of the preparation described in Example 8 has failed to yield any type of paroxetine hydrochloride anhydrate, and there is no clear teaching elsewhere in the document of any alternative route or modification to the process which would generate the anhydrate.

Paroxetine hydrochloride is also purported to be disclosed in the International Journal of Pharmaceutics 42, (1988) 135 to 143, published by Elsevier. The anhydrate is said to be produced by crystallising paroxetine hydrochloride from anhydrous propan-2-ol. Subsequent repetition of this process has resulted in a propan-2-ol solvate of paroxetine hydrochloride. That is to say that there is bound propan-2-ol in the product. This bound propan-2-ol cannot be removed by conventional drying techniques such as vacuum oven drying.

Paroxetine hydrochloride anhydrate substantially free of bound propan-2-ol has not been described in the literature, nor has any method been disclosed which would yield such a product as an inevitable result. A method for preparing paroxetine hydrochloride anhydrate substantially free of bound propan-2-ol has now been found. Furthermore, surprisingly, four new forms of paroxetine hydrochloride anhydrate have been found as have processes for their preparation. These forms are hereinafter referred to as A, B, C and D respectively. The characterising data for Forms A, B, C and D do not correspond to the characterising data provided in Example 8 of EP-A-223403.

Accordingly, the present invention provides paroxetine hydrochloride anhydrate substantially free of bound organic solvent.

The present invention also provides paroxetine hydrochloride anhydrate substantially free of bound propan-2-ol with the proviso that it is other than Form Z.

Substantially free of bound organic solvent is to be interpreted to be less than the amount of propan-2-ol which would remain solvated, i.e. bound, within the crystal lattice of the product under conventional vacuum oven drying conditions.”

Mr Waugh submitted that when the specification was read through the eyes of the skilled addressee the term “propan-2-ol” was treated interchangeably with the term “organic solvent”. Thus claim 3 contains the limitation that it has to be substantially free of bound organic solvent. That he submitted was clear from the title of the specification and the technical contribution of the patent. He submitted that the technical contribution of the patent was the explanation of how the skilled addressee could effect a lowering of the residual solvent. That was illustrated by the examples some of which showed how this could be achieved without propan-2-ol. In particular certain examples produced Form A with a different solvent from propan-2-ol. In those circumstances the skilled reader would expect the claims to equate to that technical contribution with the result that claim 3 would be read as requiring the claimed PHA to be substantially free of the bound solvent used in production and not just free of bound propan-2-ol.

Mr Waugh submitted that the construction that he advanced fell squarely between the extremes mentioned in the Protocol. To give fair protection to the patentee it was necessary to understand the claims as covering the technical contribution. That he submitted could only be done if the words “propan-2-ol” when used in the claims were construed as meaning the organic solvent used. Further there was reasonable certainty for the public as the skilled addressee would appreciate the nature of the technical contribution and read the words as he submitted they should be read.

I accept that the skilled addressee would interpret the specification taking into account the nature of the technical contribution. However he would also realise that the patentee claimed his monopoly in words of his own choosing. To disregard the apparent intention of the patentee could lead to an unfair result. In the present case, I regard the suggestion that the words “propan-2-ol” should not be given their ordinary meaning, but should be read as “organic solvent” as a deviation from ordinary rules of construction. It would do violence to the language: a result that should be avoided unless no other reasonable construction is possible.

Mr Wyand QC for BASF, rightly in my view, submitted that sense can be made of the patent without doing violence to the language. The skilled addressee would gather from the opening paragraphs of the patent what was the technical contribution that the patentee perceived had been made. In those paragraphs, 403 was acknowledged as prior art and example 8 of 403 was said to describe preparation of PHA, but repetition had failed to produce the product. Next, the Elsevier article had described production of PHA from anhydrous propan-2-ol. Repetition had produced a propan-2-ol solvate, but the propan-2-ol could not be removed by conventional drying techniques. The patent then explains that PHA substantially free of bound propan-2-ol had not been described in the prior art nor had there been a method of production which would inevitably lead to it.

The patent then explains the technical contribution. First propan-2-ol can be used when making the anhydrate and more of it can be removed than was possible using conventional drying means. The second discovery is that four new forms of PHA have been prepared.

Those two parts of the technical contribution formed the basis of the claims before amendment. Old claim 1 was directed to the first aspect and old claim 2 to the second.

Mr Wyand submitted that the paragraph in the patent which begins “substantially free of bound organic solvent is to be interpreted …” (the definition paragraph) means what it says. It is a definition of what “substantially free” meant when used with respect to any bound organic solvent. It has “to be less than the amount of propan-2-ol which would remain solvated … under conventional vacuum oven drying conditions.” The invention was the discovery of how to remove the solvent which could not be removed by conventional drying and the “benchmark” was given in relation to propan-2-ol.

In the prior art there was disclosure of about 2% propan-2-ol retained after conventional drying. The technical contribution was the way to get less than that 2%. The definition paragraph, in general words, was saying that when reference is made to a product being substantially free of bound organic solvent, it meant less than that figure.

Although the words of that paragraph are not as clear as would be wished, I accept Mr Wyand’s explanation of them as being correct. It provides a logical explanation for the wording of the rest of the patent and the claims.

That construction gives fair protection for the patentee as the claims are then limited to the technical contribution as put forward in the patent and give reasonable certainty as the words can be given their ordinary meaning. Old claim 1 had the widest ambit. It covered any PHA providing it had less than say 2% bound propan-2-ol. Old claim 2 related to the new forms of PHA that the patent says had been discovered. Old claim 3 was similar to old claim 1, but with a proviso that excluded Form Z which was the example 8 product of 403. The rest of the old claims followed in logical consequence.

After the passages quoted in paragraph 11 above, the patent gives a statement as to purity and then continues:

“It should be understood that the present invention comprising paroxetine hydrochloride anhydrate substantially free of bound propan-2-ol may contain unbound water, that is to say water which is other than water of crystallisation.”

That passage is dealing with the first aspect of the invention which is concerned with producing what was stated not to have been done before, namely PHA using propan-2-ol as the solvent.

The specification proceeds to refer to the preferred forms. It states at page 2 line 33:

“Typically the amount of bound organic solvent on a weight for weight basis would be less than 2.0% preferably less than 1.8%, more preferably less than 1.5%, even more preferably less than 1.0%, yet more preferably less than 0.5% and most preferably less than 0.1%.

Preferred forms of paroxetine hydrochloride anhydrate substantially free of bound propan-2-ol or substantially free of bound organic solvent include:

i)

paroxetine hydrochloride anhydrate in Form A; (as hereinafter defined)

ii)

paroxetine hydrochloride anhydrate in Form B (as hereinafter defined)

iii)

paroxetine hydrochloride anhydrate in Form C; (as hereinafter defined)

iv)

paroxetine hydrochloride anhydrate in Form D; (as hereinafter defined).”

The promised definitions contain analytical data of the Forms which are said to be substantially free of solvent.

It is relevant that the preferred forms of PHA are said to be “substantially free of bound propan-2-ol or substantially free of bound organic solvent”. If the submission of Mr Waugh was correct, the draftsman would not have needed to mention both propan-2-ol and organic solvent.

The process for producing the products of the invention is first mentioned at page 4 line 26.

“The present invention also provides a process for the preparation of paroxetine hydrochloride anhydrate substantially free of propan-2-ol which comprises crystallising paroxetine hydrochloride in either

i)

an organic solvent or mixture of organic solvents which form a solvate with the paroxetine hydrochloride and which are not removable by conventional drying techniques; or

ii)

an organic solvent or mixture [of] organic solvents which do or do not form a solvate but which are removable by conventional vacuum oven drying;

thereafter in the case of i) displacing the solvated solvent or solvents using a displacing agent and in the case of ii) by removing the solvent.

…

The present invention also provides a process for the preparation of paroxetine hydrochloride anhydrate substantially free of bound organic solvent which comprises displacing the solvated solvent or solvents from a paroxetine hydrochloride solvate using a displacing agent.”

These passages also follow the pattern adopted when describing the product of the invention. The first aspect is the process of producing PHA using propan-2-ol. The second is a process using other organic solvents.

The specification goes on to list a number of solvents that are suitable. It is said that they must be substantially free of water so as to prevent formation of the hemihydrate.

The patent includes a number of examples. Example 1 relates to Form A crystalline PHA “substantially free of bound propan-2-ol”. Examples 4, 5, 6, 9, 10, 11, 15, 19 and 20 also relate to Form A crystalline PHA. They are said to be “substantially free of” the solvent used in each example.

I can find nothing in the specification which would lead me to give the words “substantially free of bound propan-2-ol” used in claim 3 a meaning different to their ordinary meaning. Any perceived difficulty disappears once the definition paragraph is construed as providing a definition of substantially free of bound solvent, using the level of propan-2-ol that could not be removed by conventional drying. Thereafter the claims can be seen to cover the two aspects of the invention. The first being the ability actually to do what had been described in the prior art namely to produce PHA using propan-2-ol, but to produce it substantially free of that solvent. The second being to enable PHA substantially free of solvent to be made using other solvents.

BASF raised in their respondent’s notice other issues of construction. There is no need to deal with those issues as the parties accept that rejection of the construction issue raised by SB on appeal means that the judge was right to hold claim 3 invalid. I would therefore dismiss the appeal.

Validity – In this Court SB did not challenge the judge’s conclusion that the claims, other than claim 10(i) and claim 11 were invalid. However BASF cross-appealed contending that those claims had been anticipated and were obvious. It was accepted that the same issues arose on both claims. Therefore the cross-appeal was argued in relation to claim 11 with the agreement of both parties that claim 10(i) would stand or fall with claim 11.

Section 72(1)(a) of the Patents Act 1977 enables the court to revoke a patent if the invention is not a patentable invention. What is a patentable invention is described in section 1(1) in this way:

“1.

- Patentable inventions.

(1)

A patent may be granted only for an invention in respect of which the following conditions are satisfied, that is to say -

(a)

the invention is new;

(b)

it involves an inventive step;

…

and references in this Act to a patentable invention shall be construed accordingly.

…”

Novelty is dealt with in section 2. The relevant parts of that section are as follows:

“2.

- Novelty.

(1)

An invention shall be taken to be new if it does not form part of the state of the art.

(2)

The state of the art in the case of an invention shall be taken to comprise all matter (whether a product, a process, information about either, or anything else) which has at any time before the priority date of that invention been made available to the public (whether in the United Kingdom or elsewhere) by written or oral description, by use or in any other way.

...”

Section 3 is concerned with obviousness.

“3.

Inventive step.

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 only of section 2(2) above (and disregarding section 2(3) above).”

Novelty – The general principles to be applied were set out in my judgment in Synthon BV v SmithKline Beecham Plc [2002] EWCA Civ 1162 at paragraphs 14 to 17:

“14.

For the purposes of this appeal, there is no dispute of substance between the parties as to the principles that have to be applied when considering whether a prior published document renders a claim invalid on the ground of novelty (see sections 2(1) and 2(2)). A classic statement of the law is contained in the judgment of the Court of Appeal in General Tire and Rubber Company v Firestone Tyre and Rubber Company Ltd [1972] RPC 457 at 485:

“When the prior inventor’s publication and the patentee’s claim have respectively been construed by the court in the light of all properly admissible evidence as to technical matters, the meaning of words and expressions used in the art and so forth, the question whether the patentee’s claim is new for the purposes of section 32(1)(e) falls to be decided as a question of fact. If the prior inventor’s publication contains a clear description of, or clear instructions to do or make, something that would infringe the patentee’s claim if carried out after the grant of the patentee’s patent, the patentee’s claim will have been shown to lack the necessary novelty, that is to say, it will have been anticipated. The prior inventor, however, and the patentee may have approached the same device from different starting points and may for this reason, or it may be for other reasons, have so described their devices that it cannot be immediately discerned from a reading of the language which they have respectively used that they have discovered in truth the same device; but if carrying out the directions contained in the prior inventor’s publication will inevitably result in something being made or done which, if the patentee’s patent were valid, would constitute an infringement of the patentee’s claim, this circumstance demonstrates that the patentee’s claim has in fact been anticipated.

If on the other hand, the prior publication contains a direction which is capable of being carried out in a manner which would infringe the patentee’s claim, but would be at least as likely to be carried out in a way which would not do so, the patentee’s claim will not have been anticipated, although it may fail on the ground of obviousness. To anticipate the patentee’s claim the prior publication must contain clear and unmistakable directions to do what the patentee claims to have invented: Flour Oxidizing Co. Ltd v. Carr & Co Ltd. ((1908) 25 RPC 428 at 457 line 34, approved in B.T.H. Co. Ltd v Metropolitan Vickers Electrical Co. Ltd (1928) 45 RPC 1 at 24, line 1). A signpost, however clear, upon the road to the patentee’s invention will not suffice. The prior inventor must be clearly shown to have planted his flag at the precise destination before the patentee.”

15.

To that can be added the statement of Lord Oliver in Asahi Kasei Kogyo KK’s Application [1991] RPC 485 at 539 line 22:

“… for anticipation under subsection (2), published information requires to contain an enabling disclosure …”

16.

In that statement Lord Oliver was concluding that for matter to be “made available to the public” and therefore to form part of the state of the art, it had to enable the public to implement the disclosure.

17.

It is I believe also apposite to cite passages from the speech of Lord Hoffmann in Merrell Dow Pharmaceuticals Inc v H.N. Norton & Co Ltd [1996] RPC 76 at 89:

“My Lords, I think that on this point the Patents Act 1977 is perfectly clear. Section 2(2) does not purport to confine the state of the art about products to knowledge of their chemical composition. It is the invention which must be new and which must therefore not be part of the state of the art. It is therefore part of the state of the art if the information which has been disclosed enables the public to know the product under a description sufficient to work the invention.

…

Other decisions of the EPO seem to me to make it clear that, at least for some purposes, products need not be known under their chemical description in order to be part of the state of the art. In BAYER/Diastereomers Decision T12/81 [1979-85] E.P.O.R. Vol. B. 308, 312, the Technical Board of Appeal said:

" ... [T]he concept of novelty must not be given such a narrow interpretation that only what has already been described in the same terms is prejudicial to it. The purpose of Art. 54(1) EPC is to prevent the state of the art being patented again. Art. 54(2) EPC defines the state of the art as comprising everything made available to the public before the date of filing in any way, including by written description. There are many ways of describing a substance in chemistry and this is usually done by giving its precise scientific designation. But the latter is not always available on the date of filing ... [It] is the practice of a number of patent offices to accept the process parameter, in the form of a product-by-process claim, for closer characterisation of inventions relating to chemical substances. To the Board's knowledge this is also the practice at the European Patent Office. If inventions relating to chemical substances defined by claims of this kind are patented, it necessarily follows that the resulting patent documents, once they enter the state of the art, will be prejudicial to the novelty of applications claiming the same substance although in a different and perhaps more closely defined form.

…

Anticipation by disclosure … relies upon the communication to the public of information which enables it to do an act having the inevitable consequence of making the acid metabolite. The terfenadine specification teaches that the ingestion of terfenadine will produce a chemical reaction in the body and for the purposes of working the invention in this form, this is a sufficient description of the making of the acid metabolite. Under the description the acid metabolite was part of the state of the art.””

As was stated in the General Tire case, the particular claim must be construed so as to determine its ambit. It is only then that the court can decide whether the prior art falls within it.

In the present case there is no relevant dispute as to the ambit of claim 11. It is to a process for the preparation of PHA substantially free of bound solvent. The process has to include use of a displacement step using a displacing agent. In essence the process requires displacement of the solvent that cannot be removed by conventional drying by using a displacing agent.

Example 1 is an example of the claim 11 process of the patent. The paroxetine hydrochloride hemihydrate is stirred with inter alia propan-2-ol. That yielded solvated paroxetine hydrochloride with a propan-2-ol content of 13%. The solvate was stirred in a beaker with water. The result was crystalline PHA with a propan-2-ol content of 0.05%. It was crystalline PHA substantially free of bound propan-2-ol.

As General Tire says, the next task for the court is to interpret the prior art relied on so that the comparison can be made.

BASF rely upon GB 85-26407 (407). That application was not published by the United Kingdom Patent Office but was published in the files of 403.

407 states at its outset that the invention relates to crystalline paroxetine hydrochloride, its preparation and its use as a therapeutic agent. The hydrochloride salt is preferred and it is stated that the paroxetine hydrochloride can be produced in crystalline form in a manner reproducible on a commercial scale. There follow the consistory clauses which are in this form:

“Accordingly the present invention provides crystalline paroxetine hydrochloride as a novel material, in particular in pharmaceutically acceptable form.

It has been discovered that crystalline paroxetine hydrochloride can exist in at least two different pseudo-polymorphic forms,

1)

a hemihydrate

2)

an anhydrate

It has also been discovered that paroxetine hydrochloride can form crystalline solvates with certain solvents such as certain lower alcohols and acetone, in particular isopropyl alcohol.

Accordingly the present invention provides as novel forms of crystalline paroxetine hydrochloride:

1)

paroxetine hydrochloride hemihydrate

2)

paroxetine hydrochloride anhydrate

3)

paroxetine hydrochloride isopropanol solvate.’”

407 gives details of how to recognise both the hemihydrate and anhydrate forms. It then states:

“The solvent is fairly weakly bound and may be removed by heating under vacuum. The solvate contains approximately 1 mole of isopropanol per mole.”

It was SB’s case before the judge that that statement was in fact wrong. In this court it was accepted to be wrong. However at the date of the patent, the skilled addressee would not know that. It therefore formed part of the teaching provided by 407.

The preparation of the anhydrate is described in general terms at page 5 line 26.

“The crystalline anhydrate form of paroxetine hydrochloride may be prepared via the initial formation of a crystalline solvate e.g. propan-2-ol or acetone solvate, of the hydrochloride and followed by removal of the solvating solvent. The IPA [propan-2-ol] solvate may be conveniently obtained by crystallisation from propan-2-ol, ideally under anhydrous conditions, by adding gaseous or concentrated hydrochloric acid to a solution of the free base or acetate in propan-2-ol., or by crystallising or recrystallising preformed paroxetine hydrochloride from propan-2-ol solution. The solvent of solvation may be removed by drying, typically under vacuum at high temperature e.g. 60ºC, to give the hygroscopic anhydrate.

…

[Page 6 lines 19-25] In practice the earlier described procedure for producing the anhydrate may result in the formation of some hemihydrate. The proportion of anhydrate to hemihydrate can be increased by drying at elevated temperatures.

…

[Page 6 line 35] To obtain the anhydrate by crystallisation/recrystallisation the solvent of choice is anhydrous isopropanol.”

As the judge pointed out in paragraph 50 of his judgment, the general description provided a number of alternatives that could be used. In particular the skilled addressee would see that he could use gaseous hydrogen chloride, which is substantially anhydrous, or concentrated hydrochloric acid which is an aqueous solution.

In the opening passages of the specification there is no mention of a displacement step. The solvent is removed by drying. For that reason the thrust of BASF’s submission relied on the teaching provided by example 1. It is an example of the production of crystalline PHA. 0.341 kg of the crude paroxetine is dissolved in 3.5 litres of diluting ether and stirred with about 0.3 kg of aluminium oxide for about 3 hours. 15 gm of charcoal and 15 gm of filter aid were added and the mixture was filtered through aluminium oxide and washed with more ether. The ether solutions were combined and 66 ml of acetic acid and more ether were added. That produced paroxetine acetate which was filtered off, washed with ether and dried. The next steps are described in this way:

“The acetate salt was dissolved in isopropanol (2.4 litres) and treated with a mixture of concentrated hydrochloric acid (75ml) and more isopropanol. After standing at 0ºC for about 16 hours, the crystals of the hydrochloride salt containing isopropanol were filtered off and dried. The salt was stirred in distilled water (0.5 litres) for about 20 minutes, filtered off and dried, giving paroxetine hydrochloride anhydrate (m.p. 118ºC).”

As will appear later, it is important to decide the extent of the variation being taught by the words “and more isopropanol”. SB contended that the skilled addressee would understand that the purpose of adding more isopropanol was to aid dissolution and therefore the teaching was to add sufficient for that purpose. That could be derived from the amount used (2.4 litres for 75 ml of concentrated hydrochloric acid). BASF contended that the teaching was to add “more” and that the skilled addressee would not be surprised if much more was needed. Their evidence was that the skilled addressee would continue to add more isopropanol to ensure the anhydrate form was produced.

Example 5 is of minor importance. It is an example showing how to produce the isopropanol solvate. The detail is of no importance, but the example concludes with this sentence:

“The solvate of solution was fairly weakly bound and could be removed by drying at high temperatures.”

This is another example of the general teaching that the solvent could be removed by drying.

BASF accepted that the skilled addressee would not realise that the last sentence in Example 1 was a displacement step. That they said was irrelevant if, as was the case, example 1 disclosed a process which produced crystalline PHA free of bound organic solvent and that the use of water as described in the last sentence was a displacing step.

It was not disputed that the step in the last sentence of example 1 would act as a displacing step. It follows that if, when carrying out example 1, crystalline PHA substantially free of bound organic solvent was produced, claim 11 would lack novelty.

SB contended before the judge and in this Court that if the skilled addressee carried out example 1 he would get the hemihydrate, not PHA substantially free of organic solvent. Thus the issue at trial was whether the skilled addressee would, when performing example 1 of 407, produce the anhydrate or the hemihydrate form. To aid the respective cases both parties did experiments.

SB carried out an experiment using the amount of ingredients set out in example 1 of 407. They added 100 ml more isopropanol which was about 1/3 by volume. They obtained the hemihydrate. Thus they submitted that example 1 did not make available to the public a process within claim 1.

BASF did 6 experiments which they say illustrated what the skilled addressee would do carrying out the teaching of example 1 when read in the context of the whole specification. Experiment 1 was said to be carried out to 1/7th scale. Thus 48.7 gm of crude paroxetine base was used instead of 0.341 kg. When they came to dissolve the acetate salt in isopropanol, they failed to use 343 ml of isopropanol which would be the right amount by volume for a 1/7th scale reproduction of example 1. Instead they used 2.2 litres of isopropanol. This resulted in the isopropanol being 148 times by volume the amount of hydrochloric acid. When it came to the filtering step, it was carried out as quickly as possible on a closed filter under nitrogen and it was then dried in a stream of dry nitrogen. Form A was produced.

The important points to note are that BASF used large quantities of isopropanol and that when example 1 of 407 said “filtered off and dried”, BASF took particular care to ensure that the filtering was done quickly and the drying was efficient. The reason why they did that is tolerably clear. It is now known, after the work described in the patent was published, that the reason why the SB experiment produced the hemihydrate was that the concentrated hydrochloric acid caused problems because it is aqueous. Thus if concentrated hydrochloric acid is used the hemihydrate will result unless it is swamped by the isopropanol and steps are taken to keep the product dry.

BASF example 2 was also carried out on a 1/7th scale. About the right amount of isopropanol was used to dissolve the acetate, but 1780 ml of isopropanol was added as the “more isopropanol”. Thus the isopropanol was 166 times the volume of the concentrated hydrochloric acid. Form A was produced.

Experiment 3 used hydrogen chloride gas instead of the concentrated hydrochloric acid. Similar drying and filtering steps were used and Form A was produced.

Experiment 5 was similar to experiment 3, but 105 ml of isopropanol was added as the “more isopropanol”. Thus the isopropanol was 11 times the volume of the hydrochloric acid. However the resulting product was not left to stand for 16 hours. It was left only 15 minutes and was then filtered and dried using the procedure of example 1. The Notice of Experiments stated that a mixture of hemihydrate and the anhydrate was obtained. On the repeat the anhydrate was obtained.

The last experiment was called the supplementary experiment. It was similar to experiment 5, but the isopropanol was 13 times by volume of the hydrochloric acid. The Notice of Experiments said that a mixture of hemihydrate and anhydrate would be obtained, but on the repeat only hemihydrate was produced. The judge held that was the only admissible result.

The judge held:

“57.

If it is desired to make paroxetine hydrochloride anhydrate, Example 1 of ’407 has a problem. The production of the hydrochloride in propan-2-ol solution is carried out using concentrated hydrochloric acid, which as I have indicated is aqueous. There is obviously a risk of making a hydrate or hemihydrate rather than the paroxetine hydrochloride anhydrate propan-2-ol solvate. SB say that if you carry out the experiment fairly, that is what you get. In my judgment, the experimental evidence as a whole failed to demonstrate that production of the anhydrate substantially free of bound isopropanol was an inevitable result of following these directions. The facts are as follows.”

Having summarised the results of the experiments the judge said:

“59.

The common feature of BASF’s experiments are variations designed to enhance the anhydrous nature of the conditions under which the procedure is conducted. The direction to use concentrated hydrochloric acid, a bench reagent, necessarily involved the addition of some water. The instruction to add with it a further unspecified quantity of isopropanol (‘more isopropanol’) was followed by the addition of a very substantial quantity of isopropanol indeed (Dr Lee, with some hyperbole, described it as a swimming-pool-full), the effect being to dilute the water present substantially. In Experiment 3, the problem of the concentrated hydrochloric acid is overcome by varying the reagents so as to add HCl gas, which can be obtained substantially anhydrous.

60.

BASF Experiment 3 persuaded me that in the production of anhydrate, the problem is really the use of concentrated hydrochloric acid. I have to say that the instruction at page 5 of the specification in respect of the crystalline anhydrate, ideally to use anhydrous conditions, seems to me a clear teaching that the anhydrate is achievable, and that if a hydrate is obtained the right thing to do is to change the conditions to make them more anhydrous. But this is not anticipation. I am quite satisfied that there is no question of inevitable result in this case. If Example 1 of ’407 is repeated, the hemihydrate, not the anhydrate, will be obtained.”

I agree with the judge, but I must explain why Mr Wyand’s criticisms of that conclusion are not acceptable.

Mr Wyand submitted that the judge had been in error in that he had concluded that the issue was whether the claim 11 process was the inevitable result of following the directions in example 1 of 407. The true consideration was, he submitted, whether example 1 enabled the skilled addressee to carry out the process of claim 11 of the patent. That being so, it was necessary to consider whether example 1 of 407 provided clear and unmistakable directions of a claim 11 process.

Mr Wyand went on to submit that the requirement of an enabling disclosure was common both to section 2 of the Patents Act 1977 and the requirement of sufficiency in section 72(1)(c) (see the speech of Lord Oliver in Asahi Kasei Kogyo KK’s Application [1991] RPC 485 and that of Lord Hoffmann in Biogen Inc v Medeva Plc [1997] RPC 1). That being so, the test of what amounted to an enabling disclosure was that stated by me and approved by the Court of Appeal in Mentor Corporation v Hollister Incorporated [1993] RPC 7 at page 14 line 11:

“The test to be applied for the purpose of ascertaining whether a man skilled in the art can readily correct the mistakes or readily supply the omissions, has been stated to be this: Can he rectify the mistakes and supply the omissions [without] the exercise of any inventive faculty? If he can, then the description of the specification is sufficient. If he cannot, the patent will be void for insufficiency.”

Mr Wyand is right that “enablement” is a requirement of anticipation and sufficiency. He may be right that the standard is the same in many cases, but I do not believe it right to conclude that it is in all cases. As Lloyd LJ stated in the Mentor case, sufficiency is a question of fact and degree which depends on the nature of the invention and the other circumstances of the case. I doubt whether that applies when deciding what a prior art document has made available to the public. I therefore believe it right to follow Lloyd LJ’s example and confine myself to the law on novelty and refrain from extrapolating from statements made upon a different ground of invalidity.

Mr Wyand referred us to this passage in the speech of Lord Reid in C. Van Der Lely N.V v Bamford Limited [1963] RPC 61 at page 71:

“The law regarding anticipation derives from Lord Westbury’s statement of it in Hills v Evans (1862) 4DeG., F&J. 288. There are two branches of this statement. The first is that “a person of ordinary knowledge of the subject would at once perceive and understand and be able practically to apply the discovery without the necessity of making further experiments”. The appellants maintain that even if the skilled man could perceive in the photograph all the integers in claim 1 he could not apply the discovery without making further experiments. But Lord Westbury must have meant experiments with a view to discovering something not disclosed. He cannot have meant to refer to the ordinary methods of trial and error which involve no inventive step and are generally necessary in applying any discovery to produce a practical result. That view appears to have been generally accepted, and I need only refer to the speech of Lord Maugham in No-Fume Limited v. Pitchford (1935) 52 RPC 231. The other requirement is that “the information given by the prior publication must for the purposes of practical utility be equal to that given by the subsequent patent.” There may be cases where the skilled man has to have the language of the prior publication translated for him or where he must get from a scientist the meaning of technical terms or ideas with which he is not familiar, but once he has got this he must be able to make the machine from what is disclosed by the prior publication. This part of Lord Westbury’s statement appears to have been universally accepted, and I need only refer to the latest authority in this House, Martin v. Millwood [1956] RPC 125.”

Mr Wyand did not accept that the BASF experiments deviated from the teaching of example 1 of 407. He went on to submit that in any case the skilled addressee would analyse the intermediate and if it was not the solvate, he would realise that water was a problem and would adjust the conditions for the preparation of the intermediate so as to provide more anhydrous conditions. That would involve optimising the amount of isopropanol and ensuring that the conditions of drying and filtering avoided introduction of water. The results he would obtain were shown by the BASF experiments. He submitted that the BASF experiments were the result of ordinary methods of trial and error, not involving invention, that were necessary to apply the procedure described in example 1 and to obtain Form A of PHA as was stated to be the end product. Example 1 gave a process to produce Form A PHA and any adjustment of the process conditions that were made were the adjustments that the skilled addressee would make.

I reject those submissions for two reasons. First, for reasons that I will explain later, example 1 did not render claim 11 invalid as being obvious. Second, even if claim 11 was obvious, the BASF experiments and the SB experiment show that the process conditions of example 1 have to be altered to obtain Form A. Therefore example 1 of 407 did not make the process of claim 11 available to the public. The alterations went further than replication by a skilled addressee of the disclosure in example 1 using his ordinary skills.

General Tire makes it clear that there has to be clear and unmistakable directions to do something which will infringe the claim. Example 1 does not reach that standard. The direction to add “more isopropanol” raises doubts as to how much, and cannot be construed as a clear direction to add the large quantities used by BASF in their experiments. Further, there are no directions to carry out the careful filtering and drying steps used by BASF.

The submission that the alterations made by BASF were of the type contemplated by Lord Westbury in Hill v Evans (1862) 4DeG F&J 288 as cited by Lord Reid in Van Der Lely was based upon a misunderstanding of what was said. Lord Westbury said at page 1199:

“Now the question is, what must be the antecedent statement? I apprehend the principle is correctly thus expressed: the antecedent statement must be such that a person of ordinary knowledge of the subject would at once perceive, understand and be able practically to apply the discovery without the necessity for making further experiments and gaining further information before the invention can be made useful. If something remains to be ascertained which is necessary for the useful application of the discovery, that affords sufficient room for another valid patent.”

He went on at page 1200:

“Whatever therefore is essential to the invention must be read out of the prior publication. If specific details are necessary for the practical working and real utility of the alleged invention, they must be found substantially in the prior publication.

Apparent generality, or a proposition not true to its full extent, will not prejudice a subsequent statement which is limited and accurate, and gives a specific rule of practical application.

The reason is manifest, because much further information, and therefore much further discovery, are required before the real truth can be extricated and embodied in a form to serve the use of mankind. It is the difference between the ore and the refined and pure metal which is extracted from it.

Again, it is not, in my opinion, true in these cases to say, that knowledge, and the means of obtaining knowledge, are the same. There is a great difference between them. To carry me to the place at which I wish to arrive is very different from merely putting me on the road that leads to it. There may be a latent truth in the words of a former writer, not known even to the writer himself: and it would be unreasonable to say that there is no merit in discovering and unfolding it to the world.

Upon principle, therefore, I conclude that the prior knowledge of an invention to avoid a patent must be knowledge equal to that required to be given by a specification, namely, such knowledge as will enable the public to perceive the very discovery, and to carry the invention into practical use.”

The specific details of claim 11 of the patent cannot be read out of example 1 of 407. To get to claim 11, further information is needed. Performance of example 1 as stated provides the hemihydrate because of the water in the concentrated hydrochloric acid. The explanation by Lord Reid in Van Der Lely of what Lord Westbury said was: “He cannot have meant to refer to the ordinary methods of trial and error which … are generally necessary in applying the particular discovery to produce a practical result.” In the present case, Mr Wyand’s route to Form A via example 1 of 407 involved finding out the form of the intermediate (the solvate) and then deciding how to avoid the hemihydrate. The experiments did not seek to apply the directions in example 1. They demonstrated how Form A could be produced with alterations. That does not prove anticipation.

The same reasoning applies to experiment 3 as that involved rejecting the process described in example 1 and then delving into the specification of 407 to select hydrogen chloride gas from the general instructions.

I did not find persuasive Dr Fishwick’s evidence that the steps taken in the BASF experiments were those that would be carried out using the teaching of example 1. He is a distinguished academic chemist who played no part in planning the experiments. He read 407 at the same time as the patent. He therefore knew the answer to the difficulties of example 1 of 407. He then witnessed the repeat of the experiments. Thus his views were expressed after he knew what to do. His evidence would have been more convincing if, before seeing the patent, he had been given example 1 of 407 and had then been asked to carry out the example.

It is a curious feature of this case that the person who devised the BASF experiments was not called to give evidence. He no doubt would have been a chemist involved in the industry and would have been more representative of the skilled addressee than Dr Fishwick. He could then have explained how the experiments were devised. That evidence would have given the court a better insight as to whether example 1 of 407 made available Form A to the public. That is particularly so in this case where the results set out in the Notice of Experiments for experiment 5 and the supplementary experiment varied from those obtained when repeated. Those variations show how sensitive the results were to the process conditions. If BASF had had to expend considerable time and energy devising the experiments, would Dr Fishwick, with that knowledge, have given the evidence that he did. Those who devised the experiments must have known that they alone did not prove that example 1 made the claim 11 process available. Further evidence was needed. The best evidence would be that of a skilled addressee who without knowledge of the patent carried out example 1 and produced Form A. BASF appear not to have been able to call evidence along those lines. They relied on the opinion evidence of Dr Fishwick which could have been coloured by hindsight.

Obviousness – The judge held that claim 11 was not obvious having regard to the disclosure in example 1 of 407. His reasoning is contained in these paragraphs of his judgments:

“78.

The starting point is to assume that the skilled man has performed Example 1, and has obtained the hemihydrate. What would he do? The evidence (not least of BASF’s experiments) is that he would take all steps to remove the water, following the clear teaching at page 5 line 32 that the ideal conditions are anhydrous. Principally this means that he would use gaseous hydrogen chloride rather than concentrated hydrochloric acid, and BASF’s Experiment 3 shows, I think, that his efforts would be crowned with success. I am less impressed by Experiments 1 and 2. I do not think he would consider that the natural thing to do would be to increase the quantities of propan-2-ol so as to swamp the water unless lawyers were telling him that he had to use concentrated hydrochloric acid and the only freedom left to him was in the words ‘more isopropanol’. The crucial question is whether the final washing step would survive the drive to anhydrous conditions, or whether it would be retained.

79.

Dr Lee was satisfied that it would not. Dr Fishwick was consistent with Dr Lee in his criticisms of the SB experiments purporting to repeat Example 1 in pointing to their deficiencies in maintaining anhydrous conditions, but he thought the skilled man would retain the washing step even though he agreed that its employment was bizarre in the production of the anhydrate.

80.

Although a great deal of evidence was directed to the point, I think the answer is rather clear. Unless the skilled man were to appreciate that the particular significance in the washing step was that it was converting the propan-2-ol solvate, obtained by the hydrochlorination and crystallisation in propan-2-ol, to the anhydrate, he would obviously drop it. The specification provides him with other suggestions for the elimination of solvents in general and propan-2-ol in particular. The passages I have quoted from pages 4 and 5 of the specification (paragraphs 47 and 49 above), and the concluding words of Example 5, are clear teaching that the propan-2-ol can be removed by drying, albeit not necessarily at conventional temperatures but at high temperatures. It was not suggested that in point of fact this was true, in the sense that the propan-2-ol remaining would be in sufficiently small quantities to satisfy the claim. Thus the skilled man is taught how to remove the solvent if present, and has no need to retain the odd step of washing a material in water with a view to obtaining an anhydrate.

81.

I conclude, therefore, that the invention of claims 1 and 10 of the patent in suit are not invalid in the light of ’407.”

In the Biogen case, Lord Hoffmann explained the need for appellate caution to a judge’s conclusion on obviousness. He said:

“The question of whether an invention was obvious had been called "a kind of jury question" (see Jenkins L.J. in Allmanna Svenska Elektriska A/B v. The Burntisland Shipbuilding Co. Ltd. (1952) 69 R.P.C. 63, 70) and should be treated with appropriate respect by an appellate court. It is true that in Benmax v Austin Motor Co Ltd. [1955] A.C. 370 this House decided that, while the judge's findings of primary fact, particularly if founded upon an assessment of the credibility of witnesses, were virtually unassailable, an appellate court would be more ready to differ from the judge's evaluation of those facts by reference to some legal standard such as negligence or obviousness. In drawing this distinction, however, Viscount Simonds went on to observe, at page 374, that it was "subject only to the weight which should, as a matter of course, be given to the opinion of the learned judge". The need for appellate caution in reversing the judge's evaluation of the facts is based upon much more solid grounds than professional courtesy. It is because specific findings of fact, even by the most meticulous judge, are inherently an incomplete statement of the impression which was made upon him by the primary evidence. His expressed findings are always surrounded by a penumbra of imprecision as to emphasis, relative weight, minor qualification and nuance (as Renan said, la vérité est dans une nuance), of which time and language do not permit exact expression, but which may play an important part in the judge's overall evaluation. It would in my view be wrong to treat Benmax as authorising or requiring an appellate court to undertake a de novo evaluation of the facts in all cases in which no question of the credibility of witnesses is involved. Where the application of a legal standard such as negligence or obviousness involves no question of principle but is simply a matter of degree, an appellate court should be very cautious in differing from the judge's evaluation.”

For reasons that I will give, I believe that the judge was entitled to come to the conclusion that he did on obviousness and therefore the cross-appeal should be dismissed.

The best approach to deciding obviousness is that suggested by Oliver LJ in Windsurfing International Inc v Tabur Marine (Great Britain) Ltd [1985] RPC 59. He said:

“There are, we think, four steps which require to be taken in answering the jury question. The first is to identify the inventive concept embodied in the patent in suit. Thereafter, the court has to assume the mantle of the normally skilled but unimaginative addressee in the art at the priority date and to impute to him what was, at that date, common general knowledge in the art in question. The third step is to identify what, if any, differences exist between the matter cited as being "known or used" and the alleged invention. Finally, the court has to ask itself whether, viewed without any knowledge of the alleged invention, those differences constitute steps which would have been obvious to the skilled man or whether they require any degree of invention.”

The inventive concept of claim 1 is the idea of obtaining pure PHA by producing the solvate and then displacing the solvated solvent using a displacing agent.

In the present case there does not appear to be have been any dispute as to the common general knowledge possessed by the skilled addressee. He would be a “team” of the sort of persons that worked for BASF and SB, but would not have the ability to invent.

The essential difference between the disclosure in example 1 of 407 and the inventive concept is that example 1 produces the hemihydrate because of the water in the concentrated hydrochloric acid. Further, there is no teaching to carry out a displacing step, although the water washing step in example 1 would act in that way.

BASF’s case that claim 11 was obvious was attractively simple. The skilled addressee would, when carrying out the example, check what was the intermediate to see whether he had obtained the solvate. Upon finding that it was the hemihydrate or a mixture of the solvate and hemihydrate he would quickly realise that water was the problem. The answer was obvious, either increase the amount of isopropanol or use gaseous hydrochloric acid as suggested in the general teaching of 407. Even if he did not check the intermediate, he would realise upon obtaining the hemihydrate, not the anhydrate as taught in the example, that water was the problem and the solution was obvious.

SB’s case was also simple. Example 1 of 407 did not make the claim 11 process available to the public. It produced the hemihydrate and in any case the idea of a displacement step was not disclosed. If the skilled addressee realised that the water in the hydrochloric acid was a problem, contrary to the general teaching in 407, then water would have been avoided both before and after crystallisation.

BASF’s case was supported by the evidence of Dr Fishwick. He said that from the teaching of 407 he would seek to minimise the concentration of water. He would realise that the greater the volume of isopropanol the lower the concentration of water. He would have analysed the intermediate to see whether he had obtained the solvate. If he found significant amounts of the hemihydrate, he would reason that there had been interference by water. There were two obvious routes. “First, using dry HC1 instead of concentrated hydrochloric acid and, secondly, increasing the amount of isopropanol.” However he said in his witness statement that the water washing step in example 1 of 407 was curious and in his cross-examination he accepted that it would have seemed bizarre.

Dr Fishwick was cross-examined at length, but when his evidence is read as a whole, I believe that he maintained his views expressed in his witness statement.

Dr Lee was the relevant witness called by SB. He explained in his witness statement that example 1 of 407 did not say whether the intermediate was a solvate or not. In his view the procedure carried out by SB in their experiment was a realistic performance of example 1 of 407. He was of the view that the BASF experiments were not obvious ways of carrying out the example. If he had realised that water was the problem, he would have ensured that the conditions were anhydrous both before and after crystallisation. There was in his view no logic in taking steps to make the first half of an experiment anhydrous and then immerse the whole experiment in water in the second half. It was his view that it is only when you had read the patent that you would realise why it was necessary to exclude water in the first half and then use water in the second half as a displacing agent. That applied equally to the BASF experiments that used large quantities of isopropanol and experiment 3 which used gas.

Mr Wyand submitted that Dr Lee had resiled from that position in his cross-examination. He specifically referred us to passages in his cross-examination at Evidence 4 page 357 and at page 365. That submission is, I believe, based upon an incomplete understanding of his cross-examination.

At Evidence 4 page 357, Mr Wyand asked:

“Q. ... So you can do a check, a rough check, at that stage to see whether you have got the solvate. You know that so far as this specification is concerned, these people believe that you can put your crystals into water and you will get the anhydrate at the end of it.

A. That is written.

Q. Yes. You may doubt that, but that is what they have told you.

A. Yes.

Q. And they have told you what they got at the end of it.

A. Yes.

Q. Would it therefore not be reasonable for someone who is interested in producing the anhydrate to try it?

A. It would be one of many things that one would try, but it would not be the first line of approach. I believe that the problem had occurred much earlier on by the water at the crystallisation stage.

Q. Yes. You would try to cure that problem first.

...

MR WYAND. ... I think your answer previously was that he would take steps to remove the water at the earlier stage. What I was saying was that that is precisely what you were doing.

A. I would try to remove water at every stage.”

The judge then asked a question and Dr Lee replied:

“A. Thank you, my Lord. I will consider that I needed to avoid water in this process. The first thing I would do would be to avoid water at every stage rather than simply at again ... we differ in terminology ... the “first stage”, to use your terminology.”

That exchange emphasised Dr Lee’s evidence in his witness statement, namely if you decided to avoid water, you would do it before and after crystallisation.

On page 361 of Evidence 4, Dr Lee was asked to assume as a hypothesis that the skilled addressee, seeking to carry out example 1, would analyse the crystallised product and find that he had got the hemihydrate. Upon that assumption he was asked at Evidence 4 page 363 about the general teaching of 407.

“MR WYAND. I will ask two more questions on this. It says “ideally anhydrous” for the reaction.

A. Yes.

Q. So that teaches you two possible things. (1) You go to a truly anhydrous system, so you put aside what it says in the first part of the example, and you use an anhydrous system instead of using example 1. That is one alternative.

A. Yes.

Q. The other alternative does that not tell you that you want to work towards what you call an anhydrous system? The way you do that, within the teaching of example 1, is to lower the water concentration.

A. It is somewhat surprising on page 5 that it says anhydrous, adding gaseous or concentrated hydrochloric acid.

Q. Yes. It is surprising, therefore you want to minimise the effect of the water. That is what the ....

A. To minimise the effect, and the way to do that is to avoid it completely.

Q. If you avoid it completely, and you get the solvate, then is it not reasonable to go back to example 1 where it tells you that if you washed it in water, you got the anhydrate?

A. Yes.

Q. You may be surprised at that, but it is a reasonable thing to go back to example 1 and try what they have told you to do.

A. Yes, I mean, with further information, I would realise that the intermediate that I obtained and attempted to dry, I could not get rid of the isopropanol completely. It would be a somewhat strange approach. I have never ever come across this approach until I became involved in this case.

Q. But it is what example 1 tells you to do.

A. It is what example 1 tells one.

Q. And perhaps you would not put all of it in because you have spent time, money and effort making the solvate, but you would try it with a sample.

A. I would try it with a sample, a sort of last resort.

Q. When you say “a last resort” it is having found you have got the solvate and you do not seem to be able to dry it you say “Well, I will go back and chuck a bit in water. I do not believe it is going to work, but that is what they told me to do so I will try it.” You are not trying to say that the reasonable person would not try doing what example 1 tells you to do.

A. I accept that – but.

Q. What is “but”?

A.

This word “but” is that I am bothered with the words “more isopropanol”, what example 1 tells me to do. My reading of that is simply that there was sufficient isopropanol to wash in the hydrochloric acid. The experiments that have been performed, in my view, have been major deviations from the teaching of example 1.”

As I have said it was Dr Lee’s evidence that example 1 did not explain what was the nature of the intermediate. It was for that reason that this part of the cross-examination was put on the hypothesis that he would analyse what was referred to as the intermediate. The cross-examination then proceeded to select an alternative (hydrogen chloride gas) not used in example 1. Even so I do not read his evidence as agreeing it was obvious to reduce the water content at one stage of the process without also removing it completely. He was not asked in the passage quoted above whether it was obvious to use gaseous hydrogen chloride without taking steps to remove water completely. In any case the words of Lord Diplock in Technograph Printed Circuits Ltd v Mills & Rockley (Electronics) Ltd [1972] RPC 346 at 362 apply to Dr Lee’s cross-examination.

“The cross-examination of the respondent’s expert followed with customary skill the familiar ‘step by step’ course. I do not find it persuasive. Once an invention has been made it is generally possible to postulate a combination of steps by which the inventor might have arrived at the invention that he claims in his specification if he started from something that was already known. But it is only because the invention has been made and has proved successful that it is possible to postulate from what starting point and by what particular combination of steps the inventor could have arrived at his invention. It may be that taken in isolation none of the steps which it is now possible to postulate, if taken in isolation appears to call for any inventive ingenuity. It is improbable that this reconstruction a posteriori represents the mental process by which an inventor in fact arrived at his invention, but, even if it were, inventive ingenuity laid in perceiving that the final result which was the object of the inventor to achieve was attainable from the particular starting point and in his selection of the particular combination of steps which would lead to that result.”

I have read the relevant parts of Dr Lee’s evidence to which we were referred and I believe that, when read fairly, he maintained the view expressed in his witness statements that if he had decided to remove water at one stage of the process he would also do so at the last stage.

Faced with that evidence the judge was entitled to come to the conclusion that the process of claim 11 had not been established to be obvious. SB’s case was logical. The judge was entitled to prefer the view expressed by Dr Lee over that expressed by Dr Fishwick. I would therefore uphold his judgment on obviousness with the result that the cross-appeal should be dismissed.

Conclusion – For the reasons that I have given I would dismiss the appeal and the cross-appeal.

What is the correct approach to the construction of an ambiguous patent? Reliance has been placed on the (apparently extempore) speech of Lord Davey in Parkinson v Simon (1895) 12 RPC 403, 411:

“I entirely adopt what was said, I think, by one or two of the learned judges in the cases referred to by Mr Bousfield [Sir Richard Webster QC for the respondents had not been called upon], namely, the Skate case and the Phonograph case, that if the language of a claim be ambiguous, and it be fairly capable of two constructions, the Court would be disposed to adopt that construction which would uphold the patent, and not that which would render it invalid.”

The ‘Skate case’ was Plimpton v Spiller (1877) LR 6 Ch.D. 412, in which Lord Davey had appeared as counsel. The Court of Appeal did not touch on this question, but at first instance Sir George Jessel MR (at 422-3) said:

“… it is the duty of the judge to construe a specification fairly with a judicial anxiety to support a really useful invention if it can be supported upon a reasonable interpretation of the patent; … a judge is not to be astute to find flaws in small matters in a specification with a view to overthrow it. Any man acquainted with the patents of this county, and the patent law, knows perfectly well that is very strict, hard, and technical against inventors as it stands. The want of power to amend the specification of an invention in a trying point often prevents an excellent and useful thing, which has given the patentee the greatest trouble and anxiety and shews the exercise of remarkable powers of invention, from being secured to him merely because some slip has been made, as … is too frequently the case.”

The ‘Phonograph case’ was The Edison Bell Phonograph Corporation Ltd v Smith and Young (1894) 11 RPC 389. At the start of a judgment giving short shrift to infringers who had done “that which is common in such cases – they turn round and attack the patent”, the Master of the Rolls went on:

“… they spell every paragraph and every line in the patent, and try to persuade the court that some one line, or some one sentence in it is so bad that it makes the whole of the patent bad, and prevents the inventor from having the benefit of his invention, however useful or however great it may be. I do not hesitate to say myself, that when that is the sort of defence in such a case, the court ought to look carefully to see whether any one of those objections can be sustained. The court certainly under those circumstances ought not in any way to favour the objection. Those who take such objections must prove them strictly.”

The rest of the Master of the Rolls’ judgment illustrates this principle in practice. Kay LJ, agreeing, cited Frost on Patent Law:

“The court will construe the specification so as to support the patent if it can be fairly done, and will not be astute to find flaws in small matters in a specification with a view to overthrow it. Where any expression is ambiguous the court will endeavour to give effect to the intentions of the patentee.”

Apart possibly from the last-cited passage, none of these statements of principle and none of the other speeches in their Lordships’ house supports Lord Davey’s dictum. The current, 15^th, edition of Terrell on The Law of Patents at paragraph 6.42 illustrates the pre-1977 judicial approach by what Lindley LJ said in Needham and Kite v Johnson and Co (1884) 1 RPC 49, 58:

“I do not like the expression ‘benevolent interpretation’. I do not believe in it. The question is whether a given construction is the true construction; but, of course, if any patent is capable of more constructions than one, the general rule would be applied that you would put upon it that construction which makes it a valid patent rather than a construction which renders it invalid.”

Even this approach leans towards the patentee, in a way which Jessel MR, despite the reasons which emerge very clearly from the passage I have cited, did not. The editors state the modern position, by contrast, as follows:

“The court does not resolve doubt in favour of the patentee, as this is not part of the purposive approach to construction [fn. Assidoman Multipack v Mead [1995] RPC 321, 332]. To do so would appear to be in conflict with the Protocol insofar as it requires there to be certainty for third parties.”

They go on to cite Scanvaegt v Pelcombe [1998] FSR 786, 796 for the equal and opposite proposition that the patent is not to be construed contra proferentem.

The Protocol is not a substitute for the Convention, but the Convention itself is laconic. Article 69(1), reflected in s.125(1) of the Patents Act 1977, provides:

The extent of the protection conferred by a European patent or a European patent application shall be determined by the terms of the claims. Nevertheless, the description and drawings shall be used to interpret the claims.

The Protocol importantly amplifies this provision:

Article 69 should not be interpreted in the sense that the extent of the protection conferred by a European patent is to be understood as that defined by a strict, literal meaning of the wording used in the claims, the description and drawings being employed only for the purpose of resolving an ambiguity found in the claims. Neither should it be interpreted in the sense that the claims serve only as a guideline and that the actual protection conferred may extend to what, from a consideration of the description and drawings by a person skilled in the art, the patentee has contemplated. On the contrary, it is to be interpreted as defining a position between these extremes which combines a fair protection for the patentee with a reasonable degree of certainty for third parties.

There is nothing, it seems to me, in Article 69(1) as expounded by the Protocol which would not have been endorsed by the Victorian judges of our jurisdiction, Lord Davey apart. Because the law has historically been suspicious of monopolies for well-known reasons of public policy, there is no useful analogy between a patent and a deed or a written contract. The latter two will have been drafted for a purpose which, assuming it not to be illegal or contrary to public policy, the law will do what it properly can to uphold. A patent, by publicising an invention, makes it the patentee’s sole property for twenty years, so that the patentee’s immediate interests are in opposition to those of the rest of the world. It is in society’s longer-term interests that, by setting the two things in balance, genuine innovation should be protected and rewarded without stifling further invention. Lord Davey’s approach, and any analogue of it, would reward opaque drafting as objectionably as the infringers’ defence in cases like Edison Phonograph seeks out opacity where, on a fairminded reading, there is none. The Convention and Protocol place such exercises off limits in a way which, it seems to me, our law well understands and which sits comfortably with the wording and intent of s. 125(1).

To spell this out is not, of course, to answer any of the concrete questions in these appeals; but it is, I hope, to clear the decks for a correct approach to them. As to that approach and its outcome I respectfully agree with the judgment of Lord Justice Aldous.

I agree with the judgment of Aldous LJ.