Sandoz Patents Ltd. v. Gilcross Ltd., [1974] SCR 1336

Supreme Court of Canada

Sandoz Patents Ltd. v. Gilcross Ltd., [1974] S.C.R. 1336

Date: 1972-10-18

Sandoz Patents Limited (Defendant) Appellant;

and

Gilcross Limited, formerly Jules R. Gilbert Limited (Plaintiff) Respondent.

1972: June 14, 15; 1972: October 18.

Present: Abbott, Hall, Spence, Pigeon and Laskin JJ.

ON APPEAL FROM THE EXCHEQUER COURT OF CANADA

Patents—Description of process in specification—Standard of construction—No inventive step in mixture of substance with carrier—Patent Act, R.S.C. 1952, c. 203, s. 36(1).

A Canadian patent, No. 779,890, was issued for thioridazine and its therapeutically tolerable salts, when prepared by the process claimed. This substance is a neuroleptic drug or tranquilizer, and a derivative of the same compound, phenothiazine, as the previously known neuroleptic drug, chlorpromazine.

The specification did not give a detailed step by step description of the process for the preparation of each substance in the class of phenothiazine derivatives covered by the patent application submitted. There was a general statement that the new derivatives can be prepared by “condensing” a phenothiazine of a stated formula with a ω-halogen-alkyl-amine of a stated formula embodying, like the other, a number of possible variations.

In an action instituted by respondent claims 1,3,5, 7 and 9 of the patent were held invalid by the Exchequer Court on account of the insufficiency of the description of the bromo-ethane process in the specification. In addition, claims 10 and 11 were held invalid because they could not stand as claims in respect of any inventive step involved in the mixture of a substance with a carrier, since there is no invention involved in such a step as decided in Commissioner of Patents v. Farbwerke Hoechst A.G., [1964] S.C.R. 49. Appellant appealed from this decision and respondent entered a cross-appeal, but was not represented at the hearing of the appeal.

Held: The appeal should be allowed in part; the cross-appeal should be dismissed.

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The conclusion of the trial judge concerning claims 10 and 11 should be upheld. With regard to the other claims, they should not be held invalid. The specification sufficiently describes the invention. Although, in terms, the various steps involved in the preparation are described only for the chloro-ethane process, in fact the same steps are involved when using the bromo-ethane starting material and any person skilled in the art knows that this is what should be expected in the absence of any mention of an anomaly in the behaviour of the bromo-ethane compound.

A patent should not be invalidated on account of such a technicality, and s. 36(1) does not require it. A specification is addressed to persons skilled in the art and, therefore, is to be construed by the standard of what such a person would understand on reading it. The evidence is clear that a competent chemist reading the specification and setting out to prepare thioridazine by the bromo-ethane process would understand that the same steps are to be taken as for the chloro-ethane process.

APPEAL from a judgment of the Exchequer Court holding invalid certain claims of a Canadian patent. Appeal allowed in part; cross-appeal dismissed.

Christopher Robinson, Q.C. and Russel S. Smart, Q.C., for the appellant.

The judgment of the Court was delivered by

PIGEON J.—This appeal by Sandoz Patents Limited is from a judgment rendered by Thurlow J. in the Exchequer Court allowing in part an action instituted by the respondent Jules R. Gilbert Limited (now Gilcross Limited) and declaring that claims 1, 3, 5, 7, 9, 10 and 11 of Canadian Patent number 779,890 are invalid.

The patent in suit covers a substance called thioridazine, a neuroleptic drug or tranquilizer. The evidence shows that it is a different derivative of the same basic compound, phenothiazine, as the previously known neuroleptic drug, chlorpromazine. It gives much the same beneficial results in the treatment of mental disturbances, but without the undesirable side

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effects described by the experts as extrapyramidal reactions. These are symptoms of muscular rigidity analogous to those which characterize Parkinson’s disease.

The invention was claimed under the title “Phenothiazine derivatives substituted by a monovalent sulfur-function in 3-position”. Originally the claims covered under that heading a whole class of substances numbering in the hundreds, if not thousands. However, the patent as issued covers only thioridazine (3-methylmercapto-10-2’ - (N-methyl-piperidyl-2”) - ethyl‑1’-phenothiazine), and its therapeutically tolerable salts, when prepared by the process claimed.

The process, in the words of claim 1, “comprises condensing 3‑methylmercapto-phenothiazine with an ω-halogen-alkyl-amide” of a stated chemical formula in which one atom “is a halogen selected from the group consisting of C1 and Br”. Claims 2 and 3 cover the same process using the chloro-ethane and bromo-ethane amide respectively. Claims 4 and 5 cover “A process for the preparation of a therapeutically tolerable salt” of thioridazine using the chloro-ethane and bromo-ethane amide respectively and “then reacting the resultant base with a therapeutically acceptable acid”. Claims 6 and 7 cover the substance when prepared by the process of claims 2 and 3 respectively, claims 8 and 9, therapeutically tolerable salts when prepared by the process of claims 4 and 5.

The last claims are numbered 10 and 11. Claim 10 covers “Pharmaceutical compositions consisting essentially of a therapeutically effective amount of a compound whenever produced by the process as claimed in claim 2 or claim 3 or by an obvious chemical equivalent thereof, associated with a pharmaceutically acceptable, nontoxic carrier”. Claim 11 is identical except

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that it refers to the process as claimed in claim 4 or claim 5. In this respect, Thurlow J. said:

These last-mentioned claims, as I see it, cannot stand as claims in respect of any inventive step involved in the mixture of a substance with a carrier since there is no invention involved in such a step. Vide Commissioner of Patents v. Farbwerke Hoechst A.G. (1964 S.C.R. 49).

I agree with this conclusion of the learned trial judge and this makes it unnecessary to consider the further reasons he advanced against the validity of claims 10 and 11.

Claims 1, 3, 5, 7 and 9 were held invalid solely on account of the insufficiency of the description of the bromo-ethane process in the specification, all the other grounds of attack being rejected. As previously mentioned, the patent application as submitted covered a whole class of phenothiazine derivatives. The specification did not attempt to give a detailed step by step description of the process for the preparation of each and every substance in the class. There was a general statement that the new derivatives can be prepared by “condensing” a phenothiazine of a stated formula (formula II) “with a ω-halogen-alkyl-amine” (sic) of a stated formula (formula III) embodying, like the other, a number of possible variations. Then followed the description of the “condensation” process in the following words:

The condensation can be carried out, for example, by dissolving a phenothiazine derivative of formula II, which is substituted in 3-position by a monovalent sulfur-function, in a suitable organic solvent such for example as benzene, toluene or xylene, and then reacting the dissolved phenothiazine derivative with an ω-halogen-alkyl-amine of formula III at room temperature or at elevated temperature in the presence in the reaction mixture of an alkaline condensing agent, such for example as sodium hydroxide, potassium hydroxide, sodamide, metallic sodium, lithium hydride, sodium tert.-butylate, etc., i.e. an alkali

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metal or a compound thereof such as the hydroxide, amide, hydride or alkanolate.

The reaction can also be carried out in the absence of a solvent, by fusing the reaction partners together; in this case it is possible also to omit the condensing agent, although this may reduce the yield.

Upon conclusion of the reaction, the reaction mixture is shaken out with water, and the solvent evaporated off under reduced pressure; however, the new compounds can also be extracted from the reaction mixture by dilute mineral or organic acids and precipitated from the aqueous phase by the addition of caustic alkali or ammonia. The bases can be filtered off in those cases where they separate out of the solid state or, where they separate out as oils, can be taken up in benzene or another water-immiscible solvent and then again freed of solvent by evaporation. The bases can be purified by distillation in a high vacuum and can be converted into appropriate salts with organic or inorganic acids.

After quoting these paragraphs from the specification together with the immediately preceding paragraph embodying the “phenothiazine” and “amine” formulae, Thurlow J. said:

This is all that the specification contains by way of a description of how to prepare thioridazine by use of the bromo-ethane starting material though as previously mentioned, the preparation of thioridazine by the use of the chloro-ethane starting material is described in detail in Example 1 as an illustration of the general process and the sufficiency of this as a description of the chloro-ethane process is not challenged. There is thus in the specification a general description of a procedure for the production of a large class of substances consisting of an identification of the type of chemical procedure to use, i.e., condensation of material of one type with material of another type, plus a general description of how the procedure may be carried out as applied to the numerous materials of the two types. Thioridazine is one of the substances comprised in the group that may be so prepared. The bromo-ethane starting material is a member of one of the two types of starting materials and it may be condensed with the appropriate member of the other type of starting material, which however is not named, to produce thioridazine. The general description of the procedure for carrying

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out the condensation is not, however, confined to that in which the bromo-ethane starting material is used or to that in which either the bromo-ethane or the chloro-ethane starting materials are used to produce thioridazine. In consequence and as appears from the evidence not all the general descriptive matter would be appropriate to either of such processes and without more detailed description of them it would be necessary for a chemist to apply his knowledge to select from the general description appropriate reaction conditions, solvents, condensing agents and acids to carry out the procedure. For example, in the application of the bromo-ethane process to the production of thioridazine one of the solvents and one of the condensing agents mentioned in the general description would not work. In the case of the chloro-ethane process further information is given in Example 1 as an illustrative example of the whole general process but nowhere is the same detailed information given with respect to the bromo-ethane process either by reference to that given in the description of the chloro-ethane process in Example 1 or otherwise.

In this situation Dr. Baer gave evidence that it is well known to chemists that in such a chemical reaction a bromo-ethane compound could be expected to behave in a way that was analogous or similar to that of the corresponding chloro-ethane compound unless some anomaly in the behaviour of the bromo-ethane compound in the reaction had been reported. He himself, on the instructions of the defendant’s solicitors, had in fact prepared thioridazine after examining literature published prior to the material time but without having seen the specification or what was in it, using the chloro-ethane starting material and some time later, after having seen the specification, he had prepared thioridazine using the bromo-ethane starting material and his general knowledge of organic chemistry plus that gained in the earlier test, and he experienced no difficulty that in his opinion could not have been “tackled” by an undergraduate university student in organic chemistry.

It also appears from his evidence that he obtained no help in carrying out the bromo‑ethane process from the description in the specification, which in fact appears to have added nothing to the general chemical knowledge of how to condense materials of the defined types to produce substances of the defined class.

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Dr. Wright on the other hand while expressing the opinion that the preparation of thioridazine, as far as the chemistry is concerned, required nothing more than chemical skill, and would have been obvious to anyone familiar with what was generally known in April 1956 about the chemistry of phenothiazines took the view that the number of significant variables such as the reaction temperature, the reaction rate, the particular solvent to be used, the specific condensing agent, if any, and the quantity thereof and others was such that a great deal of time and effort would be required to find a way to successfully produce thioridazine by the bromo-ethane process in the absence of a detailed description of how to do it.

While I think that the ease with which Dr. Baer succeeded might not necessarily be experienced by everyone who would fit the description of a skilled chemist it appears to me that the general description in the specification coupled with the detailed description of the chloro-ethane process as an illustrative example, would in effect serve to remind a chemist of what he already knew that is to say that a bromo-ethane process could probably be carried out in a similar way bearing in mind known differences in bromo‑compound reactions from chloro-compound reactions, and that the addition of a detailed description of the bromo-ethane process would in fact not have done much to enhance the knowledge of or assist a qualified chemist in carrying out the process.

On the other hand the requirement of section 36(1) is that the applicant describe his invention and its operation or use as contemplated by him. The public and the reader are entitled to a description of the invention which the inventor has made and to say that a group of substituted phenothiazines may be made by a known type of chemical reaction is, as I see it, to assert merely what is already known as a general proposition rather than to say that he has carried it out in a particular way using particular materials and found that such is a practical method of producing an unexpectedly useful new substance known as thioridazine. I think moreover that Mr. Goldsmith is right in his contention that if the inventors did not carry out the bromo-ethane process they were not entitled to claim it and that if in fact they had carried it out it would have been a simple matter to describe it as they did in the case of the chloro-ethane process by a description that would give the reader precisely what was involved in their invention of the bromo-ethane process.

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That seems to me to be the standard of description which Fletcher Moulton, L.J. had in mind when he said in British United Shoe Machinery Company Ltd. v. A. Fussel & Sons Ltd. (1908) 25 R.P.C. at p. 650, which was cited by counsel for the defendant:

As it is the duty of the inventor to give the fullest practical information to the public he is bound to put in, if, for instance the invention is a process, quantities and times which are the best he knows.

Mr. Smart submitted that the invention was thioridazine and that by giving details of the chloro-ethane process the inventors were describing the best way known to them of obtaining the benefit of the invention but this as I see it ignores the fact that the bromo‑ethane process is a separate process which is a separate aspect of the invention, which has its own optimum conditions and which is separately claimed. It is I think necessary to bear in mind as well that if the bromo-ethane process was in fact invented by these inventors they must not only have carried if out but must have been the first to do so and that ex hypothesi no description of it could be available to the public in published literature. It seems to me therefore that the requirement of the statute that the applicant correctly and fully describe his invention and its operation or use as contemplated by the inventor is not fulfilled in respect of a process such as this by a specification which does not describe the particular process itself and which thus neither describes fully what has been invented nor describes its use as contemplated by him. Even though with the knowledge available and without exercising inventive ingenuity a chemist could have devised a method of preparing thioridazine by a condensation procedure involving the use of bromo-ethane starting material and the appropriate phenothiazine derivative the public is, I think, entitled to be told what method the applicant devised and employed upon which he bases his claim for a monopoly of that process. Here while the presence in the specification of a claim for the bromo-ethane process suggests that it is part of the invention of thioridazine and processes for its production the description of the invention does not even contain a bare statement (as it does in the case of the salts) that thioridazine may be prepared by a procedure essentially similar to that described in Example 1 by the condensation of 3 methyl‑mercapto-phenothiazine with the bromo-ethane starting material. Accordingly, though not without some doubt, I shall hold that the claims in respect of the bromo‑ethane

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process or dependent upon it, that is to say, claims 1, 3, 5, 7, 9, 10 and 11 are invalid.

I should add that I reach this conclusion somewhat less hesitantly than I otherwise might do, on reflecting that inventors who after making an invention which consisted of thioridazine and two processes for its preparation, one of which was by the use of a bromo-ethane starting material, instead of describing what they have done, have described as their invention a class invention which they have not invented at all, have themselves to blame if their general description is regarded as being simply what it purports to be, that is to say, a description of the alleged class invention rather than of their actual invention of a particular process for the manufacture of thioridazine. It has often been said that patent specifications are not exercises in composition and that a court will strive to uphold when it can patents for meritorious inventions. But this cannot be carried to the point of disregarding what seems to me to be a specific requirement of the statute. Nor, with patent counsel to help, should the composition of a proper description of what has in fact been invented be a task so difficult that the result should be that no description at all of a substantial portion of the actual invention is to be found in the specification though the specification is replete with description of what the applicants did not invent and though the specification has obviously been prepared with a good deal of care. (Italics added.)

On the facts the only attack against this reasoning was directed at the statement I have italicized near the end of the first quoted paragraph. It was contended that there was no evidence at all that “in the application of the bromo-ethane process to the production of thioridazine, one of the solvents and one of the condensing agents mentioned in the general description would not work”. In my view, this cannot be of very great consequence seeing that the “condensation” process is not claimed as new and it is not denied that a competent chemist, using only general knowledge available, could have successfully carried it out without more information than is supplied in the general description. Furthermore, it is not denied that

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the bromo-ethane process can be successfully carried out using the procedures and reagents that are described in Example 1 which illustrates the carrying out of the process as applied to the chloro-ethane compound. Thus, the only objection to the sufficiency of the description of the means of carrying out the invention by the bromo-ethane process is that the inventor did not say that one could proceed as in Example 1 for the chloro-ethane process, although any skilled chemist would know that this must be expected in the absence of any mention of some anomaly in the behaviour of the bromo-ethane compound in the reaction.

From the last quoted paragraph of his reasons it would appear that the learned trial judge overcame his doubt respecting the validity of this objection, by considering that the inventors had initially claimed a whole class of substances which they had not invented, instead of claiming only thioridazine prepared by the chloro-ethane or the bromo-ethane process. However, in dealing with the objection that the invention described in the specification was that of a class of substances including thioridazine, not of thioridazine itself, the learned trial judge has noted:

In the present case, as a matter of first impression, the specification purports to describe one invention, that of a class of substances, and to assert utility for all members of the class. Anyone skilled in the art would not, however, think for a moment that all members of the class had been prepared and tested but would, I think, regard the assertion as nothing but a hypothesis.

Later on, he went on to hold that, in the light of the claims as allowed, this specification written for a class of substances should be read as describing the invention of the only one of those substances mentioned in the claims, namely, thioridazine.

I agree with the submission of counsel for the plaintiff that claims for the specific substance, thioridazine, do not fit the character of the alleged class invention but when such claims are in fact found in a

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specification the specification itself takes on a different meaning from what it might otherwise have and, as I see it, it then becomes necessary to give it a practical interpretation so far as that is possible.

In my view, the same principle should be applied in reading the specification with respect to the bromo-ethane process. It is clear from the evidence that any competent chemist, setting out to prepare thioridazine by that process, would normally do as the witness Baer did. He would adopt the same procedures and use the same reagents as are described in Example 1 for the chloro-ethane process, making only such non-essential variations as a man skilled in the art would know he could safely make as, for instance, washing the acid extract with benzene instead of ether. If it had been shown that thioridazine could not be prepared by the bromo-ethane process in the same way as by the chloro-ethane process, that some special treatment or some special reagent had to be used or avoided, then it would be a question whether the operation or use of the bromo-ethane process was adequately described although the essential of the bromo-ethane process, that is the part involving inventive ingenuity, was admittedly so described. Here, however, the alleged deficiency was only in the description of the various steps involved in carrying out the invented process and, in effect, it consisted solely in the omission of an explicit statement that those steps could be the same as for the chloro-ethane process, the use of which was fully described. In my view, the proper inference from the evidence in this case is that a person skilled in the art would not need to be told that this was so.

The objection is therefore purely technical. The specification in effect fully describes not only the invention, as the learned trial judge found, but also its operation or use. Although, in terms, the various steps are described only for the chloro-ethane process, in fact the same steps are involved when using the bromo-ethane starting material and any person skilled in the

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art knows that this is what should be expected in the absence of any mention of an anomaly in the behaviour of the bromo-ethane compound. It does not appear to me that a patent should be invalidated on account of such a technicality and I do not think that s. 36(1) so requires. A specification is addressed to persons skilled in the art and, therefore, is to be construed by the standard of what such a person would understand on reading it. The evidence is clear that a competent chemist reading the specification and setting out to prepare thioridazine by the bromo-ethane process would understand that the same steps are to be taken as for the chloro-ethane process.

For those reasons, claims 1, 3, 5, 7 and 9 should not be held invalid. As this is the real point of substance on the appeal because it means that the patent in suit has some practical effect while otherwise it would have none, the appellant is entitled to costs in this Court against the respondent, but those costs will not be awarded against the trustee in bankruptcy seeing that he chose not to take up the suit. On account of this decision of the trustee, the respondent was not represented at the hearing of the appeal and its cross-appeal was not argued; it should be dismissed without costs. I would not interfere with the trial judge’s decision as to costs of the action seeing that success on the action remains divided.

On the whole, I am of the opinion that the appeal should be allowed with costs against the respondent and that the judgment of the Exchequer Court should be varied so as to hold invalid claims 10 and 11 only of Canadian Patent number 779,890, and all other claims valid and subsisting and to enjoin the defendant from infringing any of claims 1, 2, 3,4,5,8 and 9. The respondent’s cross-appeal should be dismissed without costs.

Appeal allowed with costs; cross-appeal dismissed without costs.

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Solicitors for the defendant, appellant: Smart & Biggar, Ottawa.

Solicitors for the plaintiff, respondent: Ferguson, Goldsmith & Caswell, Toronto.