What is the Promise of a Patent?

GlaxoSmithKline Inc. v Pharmascience Inc. / rosiglitazone (NOC) 2011 FC 239, Hughes J
            1,328,452 / rosiglitazone / AVANDIA

In Canadian law it is standard to say that “[w]here the specification does not promise a specific result, no particular level of utility is required; a ‘mere scintilla’ of utility will suffice. However, where the specification sets out an explicit "promise", utility will be measured against that promise” Eli Lilly Canada / olanzapine 2010 FCA 197 [76]. The notion that the utility is measured by the promise of the patent is now peculiar to Canadian law. It came to us from English law, but it is no longer a consideration in that country: Pharmacia Corp. v Merck & Co. Inc. [2001] EWCA Civ 1610 [54]. While it was raised most commonly in the utility context, it was based on the provision of the earlier Act that a patent might be revoked if “the patent was obtained on a false suggestion or representation” (see Raleigh Cycle v Miller [1948] All ER 308 (HL), 324). Both that provision as a ground of revocation, and the requirement of utility as such, were abolished by the Patents Act, 1977. The doctrine seems never to have been part of US law.

The result of the strict application of the doctrine may be that an inventor with a perfectly good invention will find its patent invalid because the invention’s virtues were exaggerated in the disclosure. This result is rare, as the courts are generally unwilling to read the promise so broadly as to invalidate a patent for an invention that is otherwise good. But that itself creates practical mischief as the validity of the patent may turn on fine points of construction of the disclosure. For example, in Miller the question was whether a “steady” light meant steady enough to provide practical illumination for a cyclists, or 50 Hertz, as had previously, but wrongly, been thought necessary for that purpose, p.325. The validity of the patent turned on this point, though word “steady” did not appear at all in the claims.

GlaxoSmithKline / rosiglitazone (NOC) 2011 FC 239 illustrates the problems with the false promise doctrine. The argument rested on the standard Canadian premise that validity turns on “utility as promised in the patent” [97]. The crucial question was whether the patent promised that rosiglitazone “will be useful,” or simply that it “was expected to be useful” [107]. As Hughes J rightly remarked, this debate is “splitting hairs” [107]. Yet the hair splitting was important; at the relevant date the patentee had established only that the compound would be potentially useful. If it had promised more, then the patent would be invalid on the false promise doctrine, even though potential utility, in Hughes J’s holding, was otherwise enough to satisfy the utility requirement. It is disturbing that patent validity should turn on this technical distinction. The real question, surely, should be whether the degree of utility established was sufficient to warrant a patent. This question is difficult enough without adding a further subjective inquiry as to what the patentee promised in the specification.

In his decision, Hughes J avoided the application of the doctrine by the usual method of interpreting the promise of the patent modestly. He held that “improved” meant better than nothing (a control), rather than better that prior art compounds; and that the promise was only that the compound has potential for use in treating diabetes, not that it would treat diabetes [94c]. In the same vein, but of more general interest, he held [94] that the word “surprising” was “self-serving and of little value one way or another in determining what is the real nature of the invention.” In effect, it is mere puffery. This is an important practical holding, given the routine use of this term, though it reinforces the broader point that the promise of the patent will not be construed strictly.

It is also significant that it is construction of the disclosure, not the claims, that are at issue. The role of the claims is to define the scope of the monopoly, and it is reasonable that its construction may be contentious, though even there the courts have cautioned against “meticulous verbal analysis” Catnic [1982] RPC 183, 243. It is perhaps not so reasonable to import the same degree of scrutiny into the construction of the specification itself; the role of the disclosure is to inform the reader about the invention, not to define the scope of the monopoly, so fine distinctions as to the meaning of particular words should not be crucial. As Hughes J pointed out in GlaxoSmithKline / rosiglitazone (NOC) 2011 FC 239 [83], “[t]here has been considerable jurisprudence as to reading a claim, which is part of the overall specification of a patent, but less jurisprudence as to how to read the description; particularly the “promise” of a patent.” Rather than developing a new body of jurisprudence on this point, perhaps it would be better to abandon the false promise doctrine entirely.