Anticipation by Prior Claiming

1A patent may be revoked on the ground that the invention claimed in any claim of the complete specification was claimed in a valid claim of earlier priority date contained in the complete specification of another patent granted in India. The wording of s 64(1)(a) is similar to s 32(1)(a) of the UK Patents Act 1949. The said ground however does not appear as a separate ground for revocation under the UK Patents Act 1977. (But prior claiming can be a ground for revoking a patent by a combined reading of ss 1(1), 2(2) and 72(1)(a) of the UK Patents Act 1977.) An application for a patent or a granted patent may be opposed on similar grounds under ss 25(1)(c) and 25(2)(c). The language of s 64(1)(a) is for all practical purposes the same as the language in ss 25(1)(a) and 25(2)(a). (The position was similar in the United Kingdom under the UK Patents Act 1949. See Daikin Kogyo Co Ltd’s (Shingu’s) Application [1973] FSR 272, pp 298-99.) The object of the above provision is to ensure that patent for the same invention is not granted to different persons.

2A claim covered by an earlier patent cannot be the subject matter of a new grant. If the invention, so far as claimed in any claim of the complete specification, was claimed in a valid claim of earlier priority date contained in the complete specification of another patent granted in India, it would be ground for revocation. (See Commercial Solvents Corpn’s Application (1954) 71 RPC 143, where the corresponding provision under s 32(1)(a) of the UK Patents Act 1949 was used to refuse an application for a patent relating to the production of riboflavin on the ground that it was covered by a prior claim.) The existence of a prior claim can have a varying impact on the later patent which is covered by an earlier claim. It may lead to the introduction of a statutory reference in the later patent or result in revocation of the later patent. The court may order revocation if the patentee fails to amend the specification appropriately to avoid the objection of prior claiming. (See Merck & Co (Macek’s) Patent [1966] FSR 381, p 387, (1967) RPC 157.)

3In Ethyl Corpn (Cook’s) Patent, Graham J stated that prior claiming could arise in the three instances: ((1970) RPC 227, p 231.)

It may, however, perhaps be useful to note that the practice of having claims in the modern form has, speaking quite generally, resulted in three typical instances where conflict arises. First, using the spatial analogy, where the earlier claim lies wholly within the area of the latter claim; secondly where the areas of the earlier and later claims are not coterminous but overlap, and thirdly where the earlier claim is broader than and includes within it the area covered by the later claim.

The first two cases can usually and should, in my judgment, continue to be dealt with in the way they are normally dealt with, namely, by amendment. The area covered by the later claim which includes or overlaps the area of the earlier claim should be excluded from it by amendment. There is then no conflict between the two claims and objection to double grant ex hypothesi no longer lies.

It is the third case which is liable to give rise to difficulties in practice and the present appeal is an instance of such a case. Here again, however, experience shows that there are mainly two alternative situations which arise – first, where the earlier and later inventors are really concerned with the same problem and provide the same solution but claim their respective inventions in words which result in the later claim being smaller in area than the earlier, and, secondly, where the two inventors can on the proper construction of their specifications and claims be seen fairly to have been addressing their minds to different problems or different aspects of the same general problem, and to have provided different or sometimes more specific solutions.

4In the first case, in order to show that an earlier claim lies wholly within the area of the later claim, one must find a distinct claim to the later invention in the earlier claim before the later claim can properly be said to be prior claimed within the meaning of the provision. (See Kromschroder AG Patent (1960) RPC 75, p 82 (CA). A case decided under the corresponding provision, s 14(1)(c) of the UK Patents Act 1949. In this case, the earlier claim was narrower and included a number of integers one of which was the subject of later claim. The integers of the earlier claim were claimed as a functional combination and therefore, the invention claimed in the later claim was different and was not the subject of a distinct claim in the earlier specification.) In the second case, a patent may be revoked on the ground of prior claiming if the earlier and the later claims overlap. (See Union Carbide Corpn’s Patent [1971] FSR 21, (1971) RPC 81, where allowing the prior claiming objection, it was held that the two claims overlapped.) In the third case, a patent may be revoked if an earlier claim is wider in scope than a later claim, and includes a separate claim in the earlier specification covering the subject-matter of the later claim. (See Daikin Kogyo Co Ltd’s (Shingu’s) Application [1973] FSR 272, (1974) RPC 559 (CA), where it was held that there was not prior claiming despite the scope of the earlier claim being wider than the later claim as there was no separate claim in the earlier specification restricted to the subject-matter of the later claim.)

5To establish prior claiming, it must be shown that the subject matter of the later claim forms the subject matter of a distinct claim in the cited specification. It will not be sufficient if the claim is ‘found some-where comprehended or described’ in the subject-matter of the claim in the cited specification. (See Daikin Kogyo Co Ltd’s (Shingu’s) Application [1973] FSR 272, p 298, (1974) RPC 559 (CA).) A comparison must be made between and limited to the claims in the two specifications. (See Kromschroder AG’s Patent (1960) RPC 75, p 79 (CA).) Two things are essential to bring a case under this ground. First, it has to be shown that the claim in issue was already claimed in a claim of earlier priority date in India, ie, anticipation by a prior claim has to be established. Secondly, it has to be shown that the earlier claim was valid.

6In Kudos Pharmaceuticals v Natco Pharma (2024) the Delhi High Court held at the interlocutory stage that “Section 64(1)(a) is clear and categorical in the words it uses. It states that the invention, so far as claimed in the suit patent, has to have been claimed in a valid claim of earlier priority date for the suit patent to be regarded as vulnerable to invalidity on the ground of anticipation by prior claiming. There has, therefore, to be identity of claims. The claim asserted in the suit patent, must have been claimed in a complete specification relating to a patent of earlier priority date.” (para 52) It reproduced from FMC Corporation v. Best Crop Science LLP that “What is required therefore, prima facie, is comparison of the claims, not whether the claim in the suit patent is covered by or within the scope of the claim in the genus patent” (para 48, pp 51–52), and held that “A claim is even more specific than a disclosure” and that “The Markush structure claimed in Claim I of the genus patent IN'218 certainly cannot be said to claim Claim I in the suit patent IN'720” (para 53).

7A claim may be a process claim or a product claim. A claim to a process producing a product is capable of being prior-claimed by a claim to a product produced by a process. An applicant who devises some new process of making the same chemical substance as an earlier patentee will not be entitled to claim that substance at all if the prior patentee has obtained a claim for the substance in the unrestricted form, but the later applicant is not debarred from claiming the new process which he has devised, subject to a proper acknowledgment of the earlier patent. (See Macfarlan & Co Ltd’s Application (1954) 71 RPC 429, p 431.)

8For the purpose of determining whether a claim is covered by a prior claim, no difference will be made out between the claim to a product and a claim to a process. Where a prior specification contained a claim of a method and the applicants’ claim was for a device, it would be ground for revocation of the later patent if there is no genuine distinction between the inventions in the two specifications. (See Standard Telephones and Cables Application (1958) RPC 108.) If, upon the construction of the earlier claim and the later claim, the court concludes that the two claims overlap with each other, a prayer for revocation will be sustainable. (See Union Carbide Corpn’s Patent [1971] FSR 21, (1971) RPC 81 (Pat App Tr). In this case, the patent in suit pertained to the production of fine grained castings by casting in a mould having on its surface a material which acts as a nucleation catalyst. The invention was characterised by the choice of a particular catalyst, ie cobalt aluminate. The patent was opposed on the ground that a claim – ‘A mould having on the casting surface thereof cobalt aluminate’ – was prior claimed by another claim – ‘The method of making a fine grained casting of an alloy in which a melt of the alloy is introduced into a mould, characterised by forming the surface of the mould in which such casting is made with a surface layer comprising a compound of the group consisting of cobalt aluminate or cobalt silicate, and cooling the alloy in the mould to below its freezing temperature to effect catalyzed nucleation of said alloy by said compound during initial solidification of the melt’. The superintending examiner upheld the prior claiming objection. The Patents Appeal Tribunal dismissed the appeal by the patentee and held that when the two claims under consideration were properly construed and their implications fully considered it was found that the monopoly obtained by the earlier claim when using cobalt aluminate and the monopoly obtained by the later claim in so far as it covers the use of the claimed mould were not different in any material respect. It was held that the two claims overlapped and the prior claiming objection was allowed.)

9Though the courts have laid tests for determining prior claiming from time to time, none of the tests are capable of universal application. (See Westinghouse Electric Corpn (Frost’s) Application [1973] FSR 173, p 179, (1973) RPC 139.) The courts have applied the ‘distinct claim’ test in Kromschroder, the ‘alternative claims’ test in Merck & Co (Macek’s) Patent and the ‘selection patent’ test in Ethyl Corpn (Cook’s) Patent in an attempt to solve the basic question of prior claiming by applying different tests and analogies. ((1960) RPC 75, p 82.) ([1966] FSR 381, p 387, (1967) RPC 157.) ((1970) RPC 227, p 231.) It would not be appropriate to lay down any specific guidelines of general application, and the conclusion on prior claiming must depend on a full study of the specifications and other relevant circumstances in each case. (See Ethyl Corpn (Cook’s) Patent (1970) RPC 227, p 231.)

10The expression ‘invention so far as claimed in any claim’ appears in cll (a), (e), (f), (g), (l) and (q) of s 64(1). The same expression also appears in the grounds of opposition in cll (b), (c), (d), (e) and (k) of ss 25(1) and 25(2). There are other phrases and expressions common in the grounds of opposition and revocation. Such phrases and expressions will be construed in the same manner under both the sections. (See Merck & Co (Macek’s) Patent [1966] FSR 381, p 386, (1967) RPC 157.)

11In construing the phrase ‘invention so far as claimed in any claim’, it has to be seen if the ‘cited prior claim on its fair construction can be seen to grant, as a manner of manufacture, that which the later claim on its fair construction would re-monopolise… despite the inclusion in the later claim of variants of the manner of manufacture to which no objection can properly be raised’. (Ibid.) To establish prior claiming, the court will have to ‘find a distinct claim in the earlier specification which, as a matter of substance, is equivalent to the claim in the later specification’. (See Clinical Products Ltd’s Patent (1963) RPC 271, p 282.) Thus, while considering questions of prior claim, one has ’to look at the matter not as a matter of language but as a matter of substance in order to ascertain whether there is any genuine or real differentiation as a matter of invention’. (See Standard Telephones and Cables Application (1958) RPC 108, p 110.) It should also be shown that the invention is found to be distinctly claimed in the earlier specification. This applies to combination of mechanical integers and invention involving chemical processes. (See Clinical Products Ltd’s Patent (1963) RPC 271, p 282.) Thus the determination of whether a claim is covered by an earlier claim will involve construction of both the earlier and the later claims.

12In AstraZeneca v Intas Pharmaceuticals (2020) the Delhi High Court held at the interlocutory stage that “the defendants’ submission that IN 625 should be revoked on account of prior claiming under the provisions of Section 64(1)(a) of the Act has substance, at least at this stage” (para 22.2). It held that “Section 13 (1) (b), simply put, allows an examiner to make use of an Indian patent application or an Indian patent which, though published, after the impugned patent bears a priority date which is earlier than the impugned patent” (para 22.3), that “the Indian genus patent i.e. IN 147 bears the priority dates 12.10.1999 and 05.04.2000 whereas the Indian species patent i.e. IN 625 bears 20.05.2002 as its priority date. For the purposes of Section 64(1)(a) this ingredient is sufficient” (para 22.4), and that “the facts in the instant suit action are closer to those which obtain in Merck & Co. (Macek’s) case. As noticed above, in the Daikin Kogyo case, the Court found that the features were different.” (para 22.9)

13The notional splitting of the claim often assists in construing the scope of a claim. It is a technique applied in the construction of the claim. The courts will notionally sub-divide a cited prior claim into each of its individual claims which must be apparent to a person skilled in the art and could be derived from the claim and then comparing these notionally subdivided claims with the applicants’ claim for anticipation. (See Merck & Co (Macek’s) Patent [1966] FSR 381, pp 384-85, (1967) RPC 157. See also Koch-Light Laboratories’ Application (1978) RPC 291, p 294.) Before ascertaining whether there can be ’notional splitting’ of a claim, ‘it must be abundantly clear that a claim so split is directed to an invention clearly delineated in the particular description and included in the claim to be split as a distinct sub-unit’. (See Imperial Chemical Industries Ltd (Small’s) Patent [1979] FSR 78, p 82.) In certain cases involving a claim to a process, it will not be proper to notionally split the claim. Thus, a claim to a process should not be interpreted as being one to a number of alternative processes, each experiment embodying one such process, but as being one to a single process capable of being carried out within certain limits of variation. (See Daikin Kogyo Co Ltd’s (Shingu’s) Application [1973] FSR 272, p 298, (1974) RPC 559 (CA). See also British Cast Iron Research Association’s Patent (1976) RPC 33, pp 47-48.)

14Every decision under s 64(1)(a) will necessarily involve the construction of at least two claiming clauses. The later claim has to be compared with the valid claim of an earlier priority date contained in a complete specification of another patent granted in India. An objection to an application on the ground of prior claiming cannot be overcome or corrected by amendment, if such amendment merely seeks to introduce what is clearly part of common general knowledge. (See Babcock & Wilcox Ltd’s Application (1952) 69 RPC 224, p 226.) Thus, the distinction between the earlier and later claim should be a matter of real distinction as to the inventive step and not mere incorporation of features of common knowledge. (See Xerox Corpn (Chatterji’s) Application (1979) RPC 375, p 377. See also Babcock and Wilcox Ltd’s Application (1952) 69 RPC 224; Commerical Solvents Corpn’s Application (1954) 71 RPC 143.)

15Section 64(1)(a) requires that the prior claim should be a valid claim. A subsequent patent can be revoked on the ground of prior claim only if the prior grant is shown to be valid. (See Mica Insulator Co v The Electrical Co Ltd (1898) 15 RPC 489. See also General Electric Co Ltd’s Patent (1959) RPC 103.) In a revocation proceeding instituted as a counter-claim in an infringement suit before the high court, the court shall presume the validity of the alleged prior claim, as it has stood unchallenged. See also Kudos, where the Court reproduced from FMC Corporation v. Best Crop Science LLP that “An allegation that the prior patent was invalid is fatal to any challenge to the validity of the suit patent under Section 64(1)(a)” (para 48).

16The words ‘claimed in a valid claim’ are not satisfied if the invention in question is only covered or comprehended by the claim as being a part or integer of some wider combination or arrangement which alone is the subject-matter of the claim. (See Badische Anilin and Soda-Fabrik AG (Distler’s) Application [1977] FSR 137, p 143.) The words at the beginning of the sub-section–‘invention so far as claimed in any claim’ – means that the subject-matter contemplated must itself be that for which protection is claimed and thus the same sense should be given to the words ‘claimed in a valid claim’ (See Kromschroder AG’s Patent (1960) RPC 75, p 82 (CA).) The date for determining the validity of a patent is the date on which the complete specification, having been accepted, is finally published and thus comes into the notice of the public who are going to perform it. (See Illinois Tool Works Inc v Autobars Co (Services) Ltd (1974) RPC 337, p 369, [1972] FSR 67.)

17The difficulty in cases of prior claiming arises from ‘a failure to realise that every decision necessarily involves the construction of at least two claiming clauses and that an appellate tribunal (or court) may arrive at a different construction from one or both and in consequence reverse a finding at first instance without adopting or intending to adopt any different principle of law’. (See Merck & Co (Macek’s) Patent [1966] FSR 381, p 383.) On a construction of the two claims, if the characteristics of the applicant’s claim can be found expressly or impliedly set out as an inventive characteristic in the prior claim, the mere existence in the applicants’ claim of alternative means of performing the invention will not avoid a finding of prior claiming if the identity of the other inventive characteristics is established. (See Willey’s Carbide Tool Co’s Application (1969) RPC 33, p 40.)

18In Kromschroder, the petitioners sought revocation of a patent relating to dry gas meters on the ground that it was covered by a prior claim. The revocation was allowed. However, the Court of Appeal, allowing the patentees’ appeal, held that the objection of prior claiming failed and granted a certificate of validity. ((1960) RPC 75 (CA).) Holding that the case pertained to construction of claims, the Court of Appeal found that the invention claimed in claim 1 of the later patent was not the subject of a distinct claim to protection in the prior patent. The Court of Appeal based its reasoning on the fact that the prior patent claimed a number of integers in combination but made no claim to one of such integers separately, while the later patent claimed one of these integers independently of its association with the others. The decision in Kromschroder has been distinguished in a number of cases. (Merck & Co (Macek’s) Patent [1966] FSR 381, (1967) RPC 157 (Pat App Tr); Union Carbide Corpn’s Patent [1971] FSR 21, (1971) RPC 81 (Pat App Tr).)

19The decision in Kromschroder was followed in Clinical Products Ltd’s Patent, where it was held that in the absence from the earlier specification of any distinct claim to the particular resin of the later specification, a statutory reference in the later specification to the earlier one will not be ordered. ((1960) RPC 75.) ((1963) RPC 271, p 280.) The case involved one specification claiming a composition comprising a particular resin which had absorbed therein any one of a class of therapeutically effective amines and a later specification claiming the method of reacting a resin of that or another type with one particular amine falling into that class. The decision in Clinical Products Ltd’s Patent was, however, explained by Lloyd-Jacob J in Merck & Company (Macek’s) Patent in the following manner: ([1966] FSR 381, p 386, (1967) RPC 157.)

The hearing officer, as appears from his decision, felt himself bound by some observations which I made in the case of Clinical Products Ltd’s Patent [1963] RPC 271 at 280. Reference to the report shows that the passage referred to formed no part of the decision, and was concerned solely to emphasise the importance of arriving at a reasoned construction of the alleged conflicting claims before attempting the task of comparing or differentiating them. That case was a difficult and perhaps borderline one wherein the construction of the claims was essential to the decision, the question being whether the prior claim could properly be regarded as the summation of a number of notional separate claims to alternative ingredients in a manner of manufacture (as the hearing officer accepted) or a claim to a generalised manner of manufacture in which the identity of the ingredients, save in the broad sense of inclusion in a chemical classification, was not essential (as I thought was possible).

20In Merck & Co (Macek’s) Patent, revocation proceedings were instituted challenging the patentee’s claim to a composition comprising novobiocin in combination with one or other antibiotic selected from penicillin, tetracycline, oxytetracycline, chlortetracycline, streptomycin and six other named antibiotics. ([1966] FSR 381, p 383.) It was alleged that the prior patent claimed a composition comprising novobiocin and a tetracycline, examples of the latter being tetracycline, oxytetracycline and chlortetracycline. Relying on earlier authorities, the patentees submitted that to establish prior claiming, it was not sufficient to show that the subject of the claim in issue was comprehended within a prior claim, but that it formed the subject of a distinct prior claim. (See Kromschroder AG’s Patent (1960) RPC 75; Clinical Products Ltd’s Patent (1963) RPC 271.) The hearing officer at the United Kingdom Patent Office held, on the basis of the above authorities that prior claiming was not established. But on appeal to the Patents Appeal Tribunal, it was held that the objection of prior claiming was established as the prior claim manifestly claims the novobiocin and tetracycline combinations to which the later claim extends. The tribunal directed revocation of the patent unless the patentee filed an application for amending the specification appropriately. (See Merck & Co (Macek’s) Patent [1966] FSR 381, p 387.)

21The issue as to whether a general formula ought to be regarded as a convenient way of specifying a number of alternatives which would occur to the reader on seeing the formula, must be a matter of degree. If the conclusion is that any particular compound would as a matter of course occur to the reader as being included within and disclosed by the formula, then it would be proper notionally to rewrite the claim so as to include specifically within its scope such a compound. (See Allen and Hanburys Ltd (Haye’s) Application (1977) RPC 113, pp 117-118.)

22Where the specification included a single claim to a compound and certain esters thereof, and where prior claiming was alleged in another specification in which there were individual claims to the same compound and to some of its esters, it was held that in determining whether there was substantial equivalence between one claim and another, it was not sufficient to merely look at the form of the claim which depended on the idiosyncrasies of the draftsman. If the invention claimed in a later claim of a specification is the subject-matter of two claims of an earlier specification, ‘a mere drafting peculiarity which has created a verbal difference importing no genuine distinction’ affords no answer to the objection of prior claiming. (See Syntex SA’s Patent (1966) RPC 560, p 563, [1966] FSR 202.)