Tuesday, October 30, 2012

Mere Verification and Anticipation

AstraZeneca Canada Inc v Pharmascience Inc / esomeprazole (NOC) 2012 FC 1189 O’Keefe J
            2,290,531 NEXIUM

As noted in my first post on this decision, here, the patent at issue claims an enteric coated pharmaceutical formulation of omeprazole using hydroxypropyl methylcellulose (HPMC) with a specified cloud point (CP) as a separating layer between the enteric coating and the active ingredient. The patent asserts that it has surprisingly been found that there is batch variation in the CP of HPMC which affects the rate of release of omeprazole. Pharmascience argued that the patent in question was not an invention on the basis that it merely ascertained the properties of a known substance [173ff]. O’Keefe J dismissed this argument, I believe correctly. However, I do have one concern.

O’Keefe J described the issue as “Is the ‘531 Patent not an invention as defined in section 2 of the Patent Act because it merely ascertains the properties of a known substance?” [92]. I suggest that this is not the best characterization of this issue. In some sense it is true that an invention that does not meet the requirements of patentability as set out in the Act is not an “invention” as that term is used in the Act, but now it is more usual to associate a particular attack with a particular established doctrine and its corresponding section. That is, we no longer say that an obvious invention “lacks subject-matter,” but rather that it is invalid for obviousness under s 28.3. Section 2 is associated with the attack that the invention is not patentable subject matter, as being, for example, a higher life form. I suggest that the argument that the invention merely ascertains the properties of a known substance is more properly considered an attack based on anticipation: see eg see King Pharmaceuticals, Inc v Eon Labs, Inc, 616 F3d 1267 (Fed Cir 2010), cited with approval on this point in Janssen Inc v Mylan Pharmaceuticals ULC / galantamine (NOC), 2010 FC 1123 at [54], treating this issue as being one of anticipation.

To see why, consider a variant of the facts. Using HPMC as a separating layer was known in the prior art, but suppose that no one else had ever measured the cloud point CP of HPMC before. Suppose further that AstraZeneca measured that CP, which did not show batch variation, though the measurement itself turned out to be very difficult, and then claimed a formulation using HPMC with that CP – that is the CP which HPMC had always possessed. Notwithstanding that there was inventive ingenuity in measuring the CP, that claim would be invalid as anticipated because the claim itself described a formulation which was known in the prior art. The knowledge of the CP was new and non-obvious, but the formulation itself would be old. Put another way, the inventive concept was new and non-obvious, but the invention as claimed was old, and validity is assessed on the basis of the invention as claimed. It is true that obviousness may sometimes be assessed with reference to the inventive concept – the contribution to knowledge – but that is because if there is no inventiveness in inventive concept, there can be no inventiveness in the invention as claimed. But the converse is not true; there may be invention in the inventive concept, but not in the invention as claimed. This is the thrust of maxim that mere verification will not support a patent. That maxim is not a free standing attack; it is merely a reflection of the requirement that the invention as claimed must be new and non-obvious.

What was different in this case is that AstraZeneca did not merely teach using the same formulation that had always been used in the prior art. The inventors discovered that there was batch variation in the CP of HPMC which affected the rate of release of the active ingredient, and the patent taught a formulation using HPMC with a specified CP that was different from what had normally been used.

[175] Conversely, AstraZeneca submits that Pharmascience’s allegation is fundamentally flawed as it is premised on an incorrect construction of the ‘531 Patent. A correct construction provides surprising teaching that the amount of product discard can be reduced by only selecting those batches of a low viscosity HPMC product that exceed the claimed CP. AstraZeneca claims that this advantage stems from the patent’s finding that the rate of release of omeprazole from an enteric coated formulation is affected by a variation in CP between different batches of the same low viscosity HPMC product. AstraZeneca submits that this teaching was clearly provided in the page 11 table of the patent, which showed one batch exceeding the marketing standard while another batch of the same low viscosity HPMC did not. As a result of a number of experiments, the patent inventors identified the claimed CP that would ensure consistent release of 75% of omeprazole within 30 minutes (i.e., at the marketing standard). Thus, AstraZeneca submits that the patent teaches that the selection of a batch of low viscosity HPMC in accordance with the claimed CP ensures the marketing standard is consistently met, which reduces the product discard associated with a failure to meet prescribed drug release requirements.

However, if we focus strictly on the invention as claimed, there is an important ambiguity in this passage. It is clear, as O’Keefe J states, that the patent teaches the use of HPMC with the specified CP. But the important question is, what did the patent claim? If the patent claims a formulation with the specified CP only if the HPMC with that CP was selected prior to coating, then the invention as claimed is not anticipated, because prior selection according to CP was not done in the prior art. But if the claims, properly construed, encompass any formulation in which the HPMC that was used has the claimed CP, then the invention as claimed may be anticipated. As I understand it, though the description of the facts in decision is not entirely clear to me on this point, the previous practice would have been to test batches after formulation and discard those which did not have an adequate rate of release. If that is so, and the inventors were right about the correlation between rate of release and CP, then the ex post selection for rate of release may have resulted in product with the claimed CP. This suggests that the prior art formulations may have fallen within the scope of the claims, in which case the invention as claimed would not be novel. Paragraph [175] is ambiguous because it refers to the construction of the "patent," and the teaching of the "patent," not the construction of the claims. If O’Keefe J meant to say that the claims only encompass the formulation when the HPMC is selected ex ante, then the conclusion that the claimed invention is novel is correct. But in that case, Pharmascience could avoid infringement by using the prior art technique and putting up with higher product discard. However, infringement was not argued, so it is not clear to me what manufacturing technique Pharmascience intended to use.

In any event, I suggest that this case illustrates that it is analytically helpful to focus on the statutory requirements for validity, rather than relying on the maxim that mere verification is not an invention.

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