Validity – whether claims anticipated by a single example in a prior art document – whether claims lack an inventive step – whether invention not a manner of manufacture because claimed compound would come into existence in natural course – whether patent obtained on false suggestion that an amendment made during prosecution made a material difference when, in fact, it did not.
In a recent decision by Justice Jessup, it appears that the Federal Court of Australia agrees with us on this point. Other grounds of invalidity pursued were lack of novelty, lack of patentable subject matter (ie not a "manner of manufacture", and that the patent was obtained on a false suggestion. All grounds failed.
The patent in suit relates to a pharmaceutical compound called N,N-dimethyl-1-[1-(4-chlorophenyl)cyclobutyl]-3-methylbutylamine hydrochloride monohydrate, which we will simply call “sibutramine". The patent is owned by Abbott GmbH & Co. KG, while Abbott Australasia Pty Ltd is the Australian licensee of the patent (collectively "Abbott").
According to the patent, sibutramine is useful in the treatment of depression, however its commercial success has primarily been as an appetite suppressant, or "weight loss" drug, marketed under brand names such as Reductil, Meridia and Sibutrex.
Apotex Pty Ltd ("Apotex") proposes to market its own weight loss drug, the active ingredient of which (Abbott contends) is sibutramine. Abbott commenced proceedings seeking to restrain Apotex, while Apotex in turn cross-claimed for invalidity of the relevant claims of the patent on grounds of lack of novelty, lack of inventive step, lack of patentable subject matter (ie not a "manner of manufacture", and that the patent was obtained on a false suggestion.
In the event, Apotex did not mount a serious defense to the infringement charge, so we will say no more on this issue.
We are most interested in the court's comments in relation to inventive step, particularly the role of obvious to try, however discussion of the case will proceed more logically if we first discuss the court's finding on lack of novelty.
Apotex relied on a single example ("Example 11") in a British patent specification, as an anticipation of claims 1 and 2 of Abbott's patent. It was common ground that Example 11 describes a procedure for preparation of sibutramine hydrochloride, ie the "non-monohydrate" form of sibutramine. While this form of the compound has similar activity, it is "hygroscopic", ie it absorbs water from the environment. This is undesirable in a pharmaceutical compound, because it is difficult to achieve a consistent weight of active ingredient in the presence of an unknown quantity of absorbed water.
The invention in Abbott's patent is the monohydrate from of sibutramine, which was found to be non-hygroscopic.
Apotex's case was essentially that by following the instructions of Example 11, the skilled person would, in fact, produce the monohydrate form, even though this was not expressly disclosed in the British patent. Abbott contended that this was neither a necessary, nor probable, outcome. Both parties called expert witnesses in support of their positions.
The law on this type of "inherent" anticipation, resulting from following a teaching in a prior art document, is well-established. The court cited a number of relevant authorities, at -, namely The General Tire & Rubber Co. v The Firestone Tyre & Rubber Co Ltd  RPC 457, H Lundbeck A/S v Alphapharm Pty Ltd  FCAFC 70, and SmithKline Beecham Plc’s (Paroxetine Methanesulfonate) Patent  RPC 10, and the following passage from Lundbeck in particular:
It may be that the prior disclosure is of a method that produces the claimed product. If that method leads inexorably to the product, there is anticipation .... If it may or may not result in the claimed product, there is no anticipation.The evidence of both sides' experts was extensive and (naturally) somewhat contradictory. Critically, however, it was agreed that unless Example 11 were followed under strictly anhydrous conditions, the result would be sibutramine hydrochloride monohydrate. The Example did not expressly require anhydrous conditions, but nor did it instruct the present or inclusion of water in any step of preparation. The question therefore arose as to whether or not the skilled person would understand Example 11 to imply anhydrous preparation, a matter on which the parties' experts disagreed.
Ultimately, the court was persuaded that the skilled person would carry out Example 11 under anhydrous conditions, or at least that it was not inevitable that a skilled person would not do so and thereby produce the monohydrate form of sibutramine (at -). Therefore the claims were not anticipated by Example 11.
INVENTIVE STEP – "OBVIOUS TO TRY"
The problem, as indicated above, was to eliminate the hygroscopic character of sibutramine. The solution claimed in Abbott's patent is to use the monohydrate form of the compound. The court was satisfied, on the evidence, that it was not a priori obvious that the monohydrate would not be hygroscopic ("[t]he circumstance that a compound was a hydrate did not mean that it would not also be hygroscopic", at ).
Citing the part of the High Court decision in Aktiebolaget Hassle v Alphapharm Pty Ltd  HCA 59 relating to "matters of routine" (at  in that decision), the Federal Court posed the question as follows (at ):
Would the notional research group at the relevant date, in all the circumstances, which include a knowledge of all the relevant prior art [and of the fact that sibutramine hydrochloride was hygroscopic] directly be led as a matter of course to try [forming the monohydrate] in the expectation that it might well produce [a non-hygroscopic compound]?One of Apotex's experts, Dr Marshall, set out an approach that he would follow in attempting to overcome the hygroscopicity problem. However, the court was not persuaded that the approach involved only "matters of routine" at the relevant time (at ):
In describing a series of different steps to which he would have had resort as a matter of routine, Dr Marshall was, in my view, in effect identifying alternatives that would have been “worth trying”, or even “obvious to try”. That approach does not appropriately address the question posed by s 7(2) of the Patents Act: Aktiebolaget Hässle 212 CLR at 438-443 -. What Dr Marshall proposed amounted, in my view, to what has been described as “[varying] all parameters or [trying] each of numerous possible choices until one possibly arrived at a successful result”: In re O’Farrell  USCA 411; (1998) 853 F.2d 894, 903, approved in Aktiebolaget Hässle at 442 .It is therefore apparent that only clearly-established, and commonplace, routine steps (ie procedures that any uninventive skilled worker would have carried out as a matter of course in the same circumstances) will support a finding of obviousness. The fact that an approach might be "worth trying" or "obvious to try," simply because the number of possible alternatives can be whittled down to a manageable number, will not lead to a finding of obviousness, on the approach taken by the Federal Court here.
PATENTABLE SUBJECT MATTER – "MANNER OF MANUFACTURE"
There is a somewhat inconvenient line of cases in Australia, starting with the High Court decision in NV Philips Gloeilampenfabrieken v Mirabella International Pty Ltd  HCA 15, that essentially stand for the proposition that even though the Patents Act 1990 generally sets out clear and separate grounds of patentability (novelty, inventive step, and so forth), it would be absurd if there were nonetheless cases in which something that would not historically have been patentable when these grounds were less distinct, should somehow now "fall through the cracks" and become patentable.
The Philips case was one in which no sound evidence was led in relation to lack of inventive step, and yet the terms in which the patent specification itself was written strongly suggested that there was no invention involved. In particular, it appeared that the old Microcell principle applied, that there was "nothing but a claim for the use of a known material in the manufacture of known articles for the purpose of which its known properties make that material suitable" (Commissioner of Patents v Microcell Ltd (1959) 102 CLR 232, a case decided under the Patents Act 1903). The High Court therefore discovered a "threshold test" of inventiveness inherent in the requirement that an invention be a "manner of new manufacture".
This is not really about "subject matter" in the conventional sense. Exactly the same claimed subject matter, if new, would be patentable.
Apotex here attempted to run a variant of the Philips attack, in the hope that this would succeed where their "inherent anticipation" attack based on Example 11 had failed.
Apotex's argument was that the Abbott patent specification itself disclosed that the hygroscopic, non-monohydrate form of sibutramine was known, and that it was an inherent property of this compound that, in taking on moisture, the monohydrate form would be produced. Therefore the skilled person would understand that the claimed compound of sibutramine was not new.
It is a rare case indeed that will succumb to the Philips threshold test, and the court soundly rejected Apotex's submissions:
The circumstance that sibutramine hydrochloride monohydrate could be prepared by leaving sibutramine hydrochloride exposed to the air does not, in my view, detract from the underlying inventiveness involved in coming up with a compound that did not previously exist. Put another way, the fact, if it be a fact, that one method of preparing the new compound may not have been a manner of manufacture does not mean that the compound itself was not a manner of manufacture. (At .)
...I am disposed to accept the submission made on behalf of the applicants that Claim 10 is put forward not as a known way to prepare sibutramine hydrochloride monohydrate, but as a statement of the scope of the monopoly marked out by by the patentee ... Thus it should not be taken from the words of the claim considered alone that sibutramine hydrochloride monohydrate would form if sibutramine hydrochloride were exposed to a gaseous medium containing water vapour. Rather, if someone did prepare sibutramine hydrochloride monohydrate that way, it would fall within the area of monopoly marked out by the patent.FALSE SUGGESTION
Apotex's "false suggestion" argument was based on a clarifying amendment made to the claims during examination in response to an objection by the examiner, as a result of which Abbott submitted that "the invention is now clearly distinguishable over the admitted prior art."
As all patent attorneys, and many patent applicants, will appreciate, "clarifying" amendments may sometimes narrow the scope of a claim (whether we admit it or not), or may simply make clear an originally-intended scope of the claim that had not bee sufficiently apparent to the examiner. The court rejected Apotex's argument that stating with an amendment that the claims are "now" distinguishable from the prior art amounts to an invalidating "false suggestion" if the amendments actually leave the scope unchanged (at 94):
The amendment proposed by the applicants merely expressed in words the essence of what they had invented, such as to make it clear that the compound was free of other hydrated forms (which it was). The suggestion that this made the invention “now clearly distinguishable” over the British patent was not, in my view, a false one.COMMENT
There is nothing new in this decision, which simply follows established precedent. However, it does so clearly and serves as a useful reminder of some key principles:
- a "paper anticipation" requires a teaching that will inevitably lead the skilled worker to make or to do something falling within the scope of the claims;
- a claim may be obvious if it covers something that can be reached from the prior art by following only routine steps, but the mere fact that something might be "worth trying" or "obvious to try" does not make it obvious;
- the Philips "threshold test" of patentability will only apply to the most blatant of cases; and
- clarifying amendments can clarify existing distinctions from the prior art, without necessarily altering practical claim scope.