Monday, November 16, 2015

I G Farbenindustrie Strikes Again

Amgen Canada Inc v Mylan Pharmaceuticals ULC 2015 FC 1244 Phelan J
            2,202,879 / cinacalcet / SENSIPAR

In Amgen / cinacalcet Phelan J held the ‘879 patent invalid over the 2,115,828 patent (which shares most of the same inventors). While this conclusion is clearly correct on the facts as found by Phelan J, there were some difficulties along the way which illustrate that the law of selection patents in Canada remains in need of clarification – or, preferably, as I have suggested in a previous post, the concept should be abandoned entirely.

The facts are reasonably straightforward. The parathyroid gland regulates calcium levels in the body through the secretion of parathyroid hormone [6]. At one time it was thought that parathyroid cells respond to calcium through a “calcium channel.” The inventors discovered that the true mechanism was a calcium-sensing receptor. This was a real breakthrough [15]. It lead to the realization that compounds that mimic the effect of calcium at the parathyroid calcium receptor could be effective in treating diseases related to poor calcium regulation [8]. Accordingly, the ‘828 patent claimed a large genus of such compounds [25].

Claim 5 of the subsequent ‘879 patent claims cinacalcet, which falls within the claims of the ‘828 patent. On the evidence, cinacalcet had no particular advantage over any of the other compounds disclosed and claimed by the ‘828 patent [70]. The patentees had initially pursued a different compound, which was specifically disclosed in the ‘828 patent [69], but when that turned out to have toxicity problems, they picked another, namely cinacalcet, with comparable properties [70]. The patentees had no particular reason to believe cinacalcet had any special properties as compared with the other compounds of the genus, as it had not even been synthesized as of the claim date of the ‘879 patent [71].

In European law the ‘879 patent would be held invalid for lack of an inventive step: there is nothing inventive in picking one compound from a class of compounds which are all known to have similar properties and discovering that it does indeed have exactly the properties one would expect. Thus inventive step, or the Canadian equivalent, non-obviousness, is all that is required to deal with invalid selection patents, as is illustrated by Barnes J’s Bortezomib decision, blogged here.

The SCC in Sanofi, 2008 SCC 61 [9]-[11], nonetheless adopted the three-stage test for selection patents derived from Maugham J’s decision in I G Farbenindustrie (1930), 47 RPC 289 (Ch), saying “Maugham J.’s analysis is consistently referred to and is well accepted.”; ironically, soon afterwards Maugham J.’s analysis was rejected in the UK as being unsound in principle: see Pharmacia [2001] EWCA Civ 1610 [60]; Dr Reddy's [2009] EWCA Civ 1362 [50], [109]. This has led to some difficulties. The FCA has strongly affirmed that improper selection is not sound basis for holding a patent invalid, saying “a selection patent is the same as any other patent” Olanzapine (No 1) 2010 FCA 197 [33]. The problem is how to reconcile this undoubted truth with the SCC’s acceptance of the I G Farbenindustrie test. The FCA’s response was to say that the notion of selection “permeates the entire analysis in relation to each of the grounds of alleged invalidity” Olanzapine (No 1) 2010 FCA 197 [32]. That is reasonable in principle, but whether it works in practice depends on the details of how the I G Farbenindustrie test is reconciled with the standard analysis. In this case, Phelan J treated each stage of Maugham J’s three-part test as a criterion necessary to validity, concluding, in effect that the ‘879 patent was invalid as being an improper selection [78]. Phelan J then turned to “other validity challenges” [79], including anticipation and obviousness, showing that Phelan J did consider the I G Farbenindustrie test to be a distinct requirement applicable to selection patents, contrary to the FCA’s holding in Olanzapine (No 1), but consistently with the SCC’s approval of that test in Sanofi.

Turning then to anticipation, Phelan J held that cinacalcet was anticipated because it was “disclosed” in the 828 patent, and “a person working Claim 1 of 828 would have made cinacalcet” [81]. However, there was no specific disclosure of cinacalcet in the ‘828 patent; more properly “a skilled medicinal chemist would have understood Cinacalcet to be a member of the class of formula compounds” disclosed in the ‘828 patent.* But this is not sufficient to establish anticipation. Despite calling it a “useful starting point,” [11] the SCC in Sanofi did not actually apply the I G Farbenindustrie test; rather, the “real question” was whether the particular selection patent at issue was anticipated [19]. The SCC specifically rejected Apotex’ argument that disclosure of the genus necessarily anticipates the species. The reason the SCC said that a system of genus and selection patents is acceptable in principle [19] is precisely that the genus does not anticipate the species, unless the species was specifically disclosed: see also 2015 FCA 137 [10]. Phelan J said that the evidence was that “a person working Claim 1 of 828 would have made cinacalcet.” I must say that I do not see anything in the evidence he reviewed to that effect. Certainly a person skilled in the art using the disclosure of the ‘828 patent might have made cinacalcet, since it did fall within the genus and the ‘828 patent enabled the making of all the compounds within the genus. But that is not enough: “If. . . the prior publication contains a direction which is capable of being carried out in a manner which would infringe the patentee's claim, but would be at least as likely to be carried out in a way which would not do so, the patentee's claim will not have been anticipated” General Tire [1972] RPC 457, 486 (CA), quoted with approval in Sanofi, 2008 SCC 61, [21], [22]. Again, this is part of the general law of anticipation; it is not a principle peculiar to selection patents.

Phelan J then considered obviousness, even though, as discussed above, the requirement that a selection patent have special advantages flows from the inventive step requirement. I began by discussing European law because even though the inventive step requirement under the EPC is equivalent to the non-obviousness requirement under s 28.3, European law has a subtle difference which makes the analysis of selection patents more transparent. Art 52(1) states that an invention must “involve an inventive step” and the question of whether the invention would be obvious to a skilled person is only the test for inventiveness under Art 56. This makes a difference, because it is intuitive to say that there is no inventive step involved in arbitrarily picking one compound from a group and discovering that it has exactly the same properties as every other member of the group. That is why this kind of pseudo-invention is known in the UK as an “arbitrary” selection: Dr Reddy's [2009] EWCA Civ 1362 [52] (and see generally my discussion here). The exclusive focus on obviousness in modern Canadian law, as opposed with inventive step, confuses the issue, because it seems natural to say that the selection of any particular arbitrary compound out of the genus is not obvious, simply because it is random. In the same way, if we spin a roulette wheel, it is not obvious which number the ball will land on, even though it is arbitrary. This has been described as the the “5¼ inch plate paradox” by Jacob LJ, but that seeming paradox is readily resolved from an inventive step perspective: Actavis UK Ltd v Novartis AG, [2010] EWCA Civ 82 [36]. The European conception of non-obviousness as being merely the test for inventive step is not inconsistent with Canadian law. Prior to codification, rather than speaking of obviousness the Canadian courts were more likely to “inventive step” or “inventive ingenuity” and alternative formulations such as whether the invention would “occur to any ordinary mind”: see eg Copeland-Chatterson Co v Paquette (1907), 38 SCR 451 at 457 (alternative formulation); Dominion Fence Co v Clinton Wire Cloth Co (1907), 39 SCR 535 at 539 (alternative formulation); Crosley Radio Corp. v. Canadian General Electric Co. [1936] SCR 551 (Inventive ingenuity, invention, inventive step); Vanity Fair Silk Mills v Commissioner of Patents,[1939] SCR 245 (invention, alternative formulation); Spun Rock Wools Ltd v Fiberglas Canada Ltd, [1943] SCR 547 (inventive step); The King v Uhlemann Optical Co, [1952] 1 SCR 143, 12 (invention, alternative formulation, obviousness); Farbwerke Hoechst [1964] SCR 49 (inventive ingenuity, obviousness); Dominion Auto Accessories Ltd v DeFrees, [1965] SCR 599 (inventiveness, inventive ingenuity). Indeed, in Halocarbon [1979] 2 SCR 929, at 934, Martland J described “obviousness” as the English term, equivalent to "inventive ingenuity" in the Canadian context. And even more pertinently, in I G Farbenindustrie Maugham J himself couched his discussion almost entirely in terms of the inventive step. He began by noting that “If for practical purposes it is not obvious to skilled chemists . . . that the selected components possess a special property, there is then, or at least there may be, sufficient ‘inventive step’ to support the Patent,” and he summarized his analysis by saying “that in a selection patent the inventive step lies in the selection for a useful and special property or characteristic adequately defined; and this is the proposition which 45 has to be kept in mind in considering the . . . the Petition for revocation” 9322-23). It is when Maugham J’s three-part test is taken as an independent rule of law, rather than read in context as part of the case, that the difficulties arise.

In holding that cinacalcet was obvious, Phelan J again noted that a skilled person “could make” cinacalcet in view of the prior art and common general knowledge [92]; but that is true of every selection patent where the genus is enabled. That alone does not make the selection invention obvious; otherwise no selection could be the basis for a valid patent, no matter how unexpected its properties as compared with the genus. Similarly, Phalen J stated that cinacalcet was obvious to try because a skilled person “would have found Cinacalcet by using known assays to screen compounds for activity at the calcium receptor” [93]. Again, that is not apparent from the evidence reviewed by Phelan J, which, so far as I can see, shows only that cinacalcet could have been found that way.

I must emphasize that the foregoing discussion has been unfair to Phelan J. He did advert in many places to evidence showing that cinacalcet was not inventive over the ‘828 patent, and it is clear that those facts drove his analysis: [41], [42], [70], [71], [82], [92]. At the end of the day, Phelan J came to the correct conclusion for the right reason. My extended discussion of the missteps along the way is intended not as a criticism of Phelan J, but as a criticism of the confused state of the law of selection patents, which makes the job of the courts far more difficult than it needs to be.

*Phelan J said that Amgen conceded that cinacalcet “was disclosed in the prior art” [64] and that it was “disclosed in 828 and WO 959" [81], but it was not specifically claimed in either of those documents. While I have not scoured them for specific references, cinacalcet was only synthesized in early 1995, after the claim date of the ‘879 patent [71], and three years after the filing date of the ‘828 patent, and even the ‘828 patent barely mentioned it [76]. From that I conclude that it was not specifically disclosed in the ‘828 patent.

No comments:

Post a Comment