Case: Alphapharm Pty Ltd v H Lundbeck A/S [2008] FCA 559
Outcome: discussed
The present cases are applications for revocation of a patent pursuant to s 138(3) of the Patents Act 1990 (Cth) (the 1990 Act). The patent claims an enantiomer of a racemate where that racemate was disclosed and claimed by an earlier patent. This has been an issue in relation to other compounds, most recently in two judgments published after the close of evidence and, in one case, after the close of addresses the decision of Lindgren J in Alphapharm Pty Ltd v H Lundbeck A/S [2008] FCA 559 and the decision of the Full Court in Ranbaxy Australia Pty Ltd v Warner-Lambert Co LLC [2008] FCAFC 82 respectively. 49 Counsel for Sanofi-Aventis submitted that enabling disclosure, not mere disclosure, is required for anticipation, citing, most recently, Lindgren J in Alphapharm Pty Ltd [2008] FCA 559 at [160] [161] and the decision of the House of Lords in SmithKline Beecham (Paroxetine Methanesulfonate) Patent [2006] RPC 323. By way of introduction, it is worth remarking that the phrase "enabling disclosure" was brought to prominence by the speech of Lord Hoffmann in Biogen Inc v Medeva plc [1996] UKHL 18 ; [1997] RPC 1 , (1996) 36 IPR 438. That decision concerned the requirements for a valid patent under the 1997 United Kingdom Act (based upon the European Patent Convention) but did not concern the question of anticipation. The most important question was whether a later patent could claim an earlier priority date because it was "supported" by the earlier specification. That is a concept similar to, but narrower than, whether a later patent is fairly based upon an earlier specification in our law (cf F Hoffman-La Roche &amp; Co AG v Commissioner of Patents [1971] HCA 3 ; (1971) 123 CLR 529 ; CCOM Pty Ltd v Jiejing Pty Ltd [1994] FCA 1168 ; (1994) 51 FCR 260 ; Lockwood Security Products Pty Ltd v Doric Products Pty Ltd [2004] HCA 58 ; (2004) 217 CLR 274). It may be accepted that, in the case of a claim for a chemical compound by formula, in order to be valid, the specification would have to disclose how it might be manufactured (s 40). The phrase was also used in the speech of Lord Oliver in Asahi Kasei Kogyo KK's Application [1991] RPC 485 , to which I shall return. The phrase is reasonable shorthand in relation to the disclosure required for there to be anticipation of a process or method claim but, in my opinion, has little, if any, relevance to anticipation of a product claim or a claim for a chemical compound by formula. Indeed, it is apt to mislead in relation to the latter. For a product claim, the novelty must lie in the product not the means of producing it ( May &amp; Baker Ltd v Boots Pure Drug Co Ltd (1948) 65 RPC 255 at 281 282). By the same token, a new process to obtain an old product will have novelty. 67 Lindgren J dealt with a somewhat similar situation in Alphapharm [2008] FCA 559 although, in that case, there was no express reference to, or claim to, the enantiomers of the racemate in the alleged anticipation. His Honour had construed the relevant claims of the patent in suit as relating only to the (+)- or dextro-rotatory enantiomer of citalopram, having a separate existence, not being an indistinguishable part of the unresolved racemate. His reasoning included the following ( Alphapharm [2008] FCA 559 at [118] [119]): "The only context that I take into account in arriving at this conclusion is that it was part of common general knowledge: &#8226; that racemates contained in equal parts (+) and ( ) enantiomers; &#8226; that the enantiomers of a racemate were potentially separable, and it was a possibility that an enantiomer might have a stable existence as a compound distinct from being part of the racemate; &#8226; that some racemates had in fact been resolved into their separate enantiomers; and &#8226; that racemates were commonly represented by the symbol (+/-) to indicate the presence of both enantiomers. It is not that the (+)-citalopram compound does not exist when it is part of the racemate. The skilled addressee would understand that it exists whether a part of the racemate or apart from it, and that the purpose of the (+) symbol is only to distinguish it from the ( )-enantiomer and from its being merely part of the racemate or of some other mixture. The (+) or ( ) symbol, devoid of any context suggesting otherwise, implies distinctness from the racemate." In Alphapharm [2008] FCA 559 , Professor Martin Banwell was called by the applicant for revocation, as he was in these cases. 68 After referring to the well-known passage from General Tire &amp; Rubber Co [1972] RPC 457 at 485 486 and citing various other cases, his Honour said ( Alphapharm [2008] FCA 559 at [161] ): "What does "enabling disclosure" mean in the context of a product claim? It means that the earlier disclosure must point unmistakeably to the (+)-enantiomer of citalopram, as distinct from the racemate, as a drug desirable to obtain." I take "as distinct from" to mean "separately from" not "instead of" or "as opposed to". This does not include any separate requirement of enablement in accordance with SmithKline Beecham (Paroxetine Methanesulfonate) Patent [2006] RPC 323 and is consistent with my opinion. 69 It was alleged that the product claims of the patent in suit in that case were anticipated by the Australian Citalopram Patent. His Honour rejected the argument on the following basis ( Alphapharm Pty Ltd [2008] FCA 559 at [171] [173]): "The Australian Citalopram Patent did not refer to "enantiomers". It did not expressly or by implication otherwise disclose the individual enantiomers. It disclosed the racemate and enabled the obtaining of it. Whether this anticipated the present invention turns on my construction of the Patent see Section C above. The skilled but non-inventive addressee reading the Australian Citalopram Patent would have understood that (+/-)-citalopram consisted of the (+)-enantiomer of citalopram and the (-)-enantiomer, each as to 50%, and would have been able to identify the formulae for the S and R enantiomers, but would not have known, in the absence of experimentation, which was (+) and which was (-). These facts would not, however, point specifically to the independent existence of the enantiomers which is, according to my construction of the Patent specification, of the essence of claim 1. If I had construed claim 1 as referring to (+)-citalopram when present in the unresolved racemate, the Australian Citalopram Patent would have been an anticipation. But because of my construction outlined at Section C above, a person taught by the Australian Citalopram Patent, although taught to desire to obtain the racemate, would not be taught to desire to obtain the specific (+)-enantiomer in its own right. Similarly, the Australian Citalopram Patent's citalopram formula did not disclose the independently existing (+)-enantiomer. I note that if In re Adamson (1960) 275 F2d 952 is authority for the proposition that a patent for a racemate necessarily anticipates a claimed invention of either of its enantiomers, I respectfully disagree." 70 A little earlier than the decision in Alphapharm [2008] FCA 559 , Young J had considered a similar issue in Ranbaxy Australia Pty Ltd v Warner-Lambert Co LLC (No 2) [2006] FCA 1787 , (2006) 71 IPR 46. One question was whether the formula in claim 1 of the relevant patent claimed only the racemate and not the enantiomers separate from the racemate. The patentee, Warner-Lambert, called, amongst other witnesses, Professor Christopher Easton and Professor Peter Scammells, who gave evidence for Sanofi-Aventis in these cases. The applicant for revocation, Ranbaxy, called, inter alia, Dr Keith Watson, who was called by Apotex, one of the applicants, in these cases. His Honour's findings about common general knowledge (so far as is relevant) were as follows ( Ranbaxy [2006] FCA 1787 , 71 IPR 46 at [113] ): "(7) The biological activity of a racemate in a biological system can be quite different from that of a single enantiomer. The physical and biological properties of a racemate differ from that of an individual enantiomer in various respects: for example, there may be differences in solubility between the racemate and its enantiomers and differences in pharmacological properties. (8) The normal expectation is that there would be one enantiomer that is approximately twice as active as the racemate in terms of its operation in the target biological system. (9) Before 30 May 1986, the skilled team would expect that the R enantiomer was very likely to be the active, or more active, enantiomer, but this could not be known with certainty without isolating and testing the enantiomer. (10) Conversely, it was very likely to be the case that the S enantiomer was inactive, or substantially less active, than the R enantiomer, but this could not be known with certainty until the enantiomers had been isolated and tested. (11) Well before 30 May 1986, it was common general knowledge amongst medicinal chemists that racemic mixtures could be separated into the individual enantiomers by well-known methods of resolution. Indeed, undergraduate chemical students were taught procedures to resolve enantiomers. It was also generally known before May 1986 that enantiomers could be obtained by chiral synthesis. (12) As at 30 May 1986, it was feasible to use resolution or chiral synthesis to obtain a single enantiomer drug. Pharmaceutical companies had produced single enantiomer synthetic drugs either by way of resolution from the corresponding racemic mixture or by way of chiral synthesis prior to May 1986. (13) As at May 1986, it was known that enantiomers could have different biological properties and that it may be desirable to separate and remove the less active enantiomer." 73 Although the decisions in Alphapharm [2008] FCA 559 and Ranbaxy [2006] FCA 1787 , 71 IPR 46 turned in large measure upon the evidence in each case, a difference in approach can be detected on the question involving the disclosure of enantiomers, with Ranbaxy [2006] FCA 1787 , 71 IPR 46 favourable to the applicants on this issue, and Alphapharm [2008] FCA 559 being neutral. In neither case was there the express reference to enantiomers such as there is in the French and corresponding patents here. The priority dates of the relevant patents are also interesting when compared with the priority dates in issue here. In Ranbaxy [2006] FCA 1787 , 71 IPR 46 , the priority date of the broader patent was 30 May 1986 and that of the enantiomer patent 21 July 1989. In the case of Alphapharm [2008] FCA 559 the Australian Citalopram Patent had a priority date of 14 January 1976 and the enantiomer patent 14 June 1988. The common general knowledge found by Lindgren J to relate to the enantiomer patent and by Young J to relate to the broader patent was very much in the same time band as that relevant to construction of the patent in suit here. Naturally, the field of each invention is somewhat different but the principles of stereochemistry as they were understood at the time should not have varied much. There is no suggestion of any crucial and widely known developments during the years in question.