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:

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:

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:

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:

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.

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:

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

Section 3 is concerned with obviousness.

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:

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:

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

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.

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:

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:

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:

Having summarised the results of the experiments the judge said:

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:

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:

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:

He went on at page 1200:

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:

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:

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:

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:

The judge then asked a question and Dr Lee replied:

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.

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.

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:

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:

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:

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:

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:

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.