Promise of the Patent Determined Without Reference to the Description

Pfizer Canada Inc. v. Apotex Inc. / latanoprost (NOC) 2011 FCA 236 Trudel JA; Sharlow, Stratas JJA rev’g 2010 FC 447 Heneghan J 

There is not much new law in the FCA’s latest latanoprost decision, but it is significant nonetheless for an extremely aggressive application of the false promise doctrine; the FCA construed the promise of the patent without any reference to the description, and, on the basis of this construction, reversed the Applications Judge and held the claims at issue invalid.

The key claims in the patent at issue, 1,339,132, were a compound claim for latanoprost, a prostaglandin derivative, and a claim for the use of latanoprost in the treatment of glaucoma or ocular hypertension. Prostaglandins had previously been of interest in treating glaucoma, but most (or all) of the prior art prostaglandins were of limited practical use for that purpose because of side effects, primarily ocular irritation.

A crucial issue on appeal was the construction of the promise of the patent. According to standard Canadian law, the utility of the invention is measured by the promise of the patent. This means that even if the invention is sufficiently useful to warrant a patent, the patent will nonetheless be invalid for lack of utility if it promises more than it delivers. At the first instance, Apotex’s argument, which was rejected by Heneghan J, was that the patent promised that side effects would be eliminated or substantially reduced in chronic treatment of glaucoma [FC 69, 192]. The issue was significant because the inventors had only conducted “single dose” studies of eye irritation caused by latanoprost. If the patent promised reduced irritation when given as a single dose, then, as Heneghan J held, demonstrated utility was established. This was not disputed on appeal. Thus it is clear that the invention had that “scintilla” of utility that is accepted as being adequate to satisfy the utility requirement if no higher degree of utility is promised. But if, as Apotex argued, the patent promised that irritation would be reduced even with chronic use, utility depended on sound prediction. The Court of Appeal agreed with Apotex as to the promise of the patent, and in the second issue on appeal, went on to hold that the factual basis for a sound prediction was not established by the single dose studies, and consequently the claims in question were invalid.

So, validity turned on the construction of the promise of the patent, and specifically whether the patent promised that irritation would be minimal even with chronic use. The FCA reviewed the question for correctness as a matter of law [17], and having determined that Heneghan J erred in her interpretation of the promise, came to its own conclusion based on the record, without remitting the matter to Heneghan J [20].

Is Claim Construction Really a Question of Law?

Phostech Lithium Inc v Valence Technology, Inc 2011 FCA 237 Pelletier JA: Noël, Mainville JJA, affirming 2011 FC 174, Gauthier J 

The trial decision of Gauthier J in Valence v Phostech turned primarily on the facts, and it is no surprise that the FCA has affirmed, in an appeal that “raises no novel questions of law” [1].

The invention in question was for a method for making lithium mixed metal cathodes for lithium ion batteries by using “carbothermal reduction” (CTR). The main issue at trial was whether the process used by Phostech, the defendant, used CTR. As a matter of science it was difficult to determine whether the conditions inside the closed industrial kiln used by Phostech would actually result in CTR, but the question, which Gauthier J decided against Phostech, was purely factual. Phostech chose, no doubt wisely, not to even raise this point on appeal.

Instead Phostech focused on a claim construction point. As the FCA noted, claim construction is a question of law, so the standard of review is correctness [26]. While this point is well settled, this characterization of claim construction has always struck me as a bit odd. The claim is construed as it would be understood by a person skilled in the art, which means that the trial judge must receive expert testimony as to the meaning of various terms and the background necessary to understand the technology, then use this factual information to put herself in the shoes of a skilled person reading the claims, before determining the meaning of the claims. This looks to me quite a lot like a question of mixed fact and law. In Phostech this FCA squared this circle by noting that “[w]hile the interpretation of the [term in issue] is a question of law, it must be construed in the light of the evidence as to its meaning to the person skilled in the art” [29]. The FCA then noted that the trial judge heard conflicting expert evidence, and preferred that of the plaintiffs’ [30], and after two paragraphs quoting from the trial judge’s summary of the evidence, concluded “the trial judge’s interpretation of the [term in issue], resting as it does on the evidence which she accepted as to the person skilled in the art’s understanding of the term, is unassailable” [33]. This looks quite a bit like a deferential review that would be applied to a question of mixed fact and law.

My thanks to Alan Macek and his very useful site IPPractice.ca for bringing this case to my attention before it was released on the FCA website.

Week of 14 August - No Decisions

No non-procedural patent decisions were released on the Federal Courts' websites for the week of 14 August.

Week of 7 August - No Decisions

No non-procedural patent decisions were released on the Federal Courts' websites for the week of 7 August.

Week of 31 July - No Decisions

No non-procedural patent decisions were released on the Federal Courts' websites for the week of 31 July.