What was the "promise of the patent doctrine"?

What was the "promise of the patent doctrine"?  The short answer is: a controversial doctrine that originated in English law and that, until recently, was applied in Canadian patent law to invalidate patents that made a material false promise about the utility of the invention. A common example would be a claim to therapeutic efficacy in a specification that is not born out.

Warning: the content of this doctrine this may seem bizarre to those familiar with U.S. patent law.

I learned of the "promise of the patent doctrine" at PatCon9 from Norman Siebrasse, Professor of Law at University of New Brunswick, and founder of the Canadian patent blog: Sufficient Description. Siebrasse provided an in depth analysis of what he calls the"promise of the patent doctrine," or just the "Promise Doctrine," in a 2013 article  in a Canadian law journal. He discussed it further on several posts on Sufficient Description, leading up to the Supreme Court of Canada's decision to abolish the doctrine in AstraZeneca Canada Inc. v. Apotex Inc. (2017).

According to Professor Siebrasse, pre-abolishment, Canadian utility doctrine effectively had "two branches": (1) the "traditional utility requirement," which is similar to U.S. law's, and requires merely a "scintilla" of utility; and (2) "the Promise Doctrine."

The basic idea of the Promise Doctrine was that

"where 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." (quoting Lilly v Novopharm / Olanzapine) 

Starting around 2005, until the Supreme Court of Canada's decision in AstraZeneca, Canadian courts applied the Promise Doctrine in the pharmaceutical context to invalidate patents. The "promise," Siebrasse explained, could be found "anywhere in the specification[.]" If there were  multiple “promises," the patent had to satisfy all of them, or the entire patent would be invalidated.

Here is an example from Siebrasse's article.  (35-36). In a Canadian case circa 2009, a judge construed a patent as making a "promise" of a certain utility based on the following statements, in bold italics, within the patent specification:

The compounds of this invention have useful pharmacological properties. They are useful in the treatment of high blood pressure. The compounds of the present invention can be combined with pharmaceutical carriers and administered in a variety of well-known pharmaceutical forms suitable for oral or parental administration to provide compositions useful in the treatment of cardiovascular disorders and particularly mammalian hypertension. (35) (citing Sanofi v Apotex/ramipril).    

The patent would be invalidated under the Promise Doctrine if the promise of utility turned out to be false—or if the court deemed the promised of utility to be premature and unfounded at the time of filing. This is an important caveat, because, Professor Siebrasse explains, in essentially all the Canadian cases invalidating the patent on the basis of the Promise Doctrine, the promise was in fact true. It's just that the heightened promise of utility was speculative at the time of filing. Only later was it was proven to be true later, when validity was challenged in court.  So it's not just that the applicant makes a "false" promise; it's that the applicant makes a promise on which s/he may not be able to deliver.

Professor Siebrasse was not happy about courts' use of the Promise Doctrine to invalidate patents.  His view seems to have won out in AstraZeneca, where the Court's language, at least to me, suggests the Doctrine is unambiguously dead:

"...the Promise Doctrine is not the correct method of determining whether the utility requirement under s. 2  of the Patent Act  is met. Given the correct approach, as set out below, the drug for which the ‘653 patent was granted is useful as a PPI; thus, it is an “invention” under s. 2 of the Act. The ‘653 patent is therefore not invalid for want of utility."          

Siebrasse gleefully keeps watch on the Promise Doctrine's fate in posts with titles like "Whack the Zombies Dead Once and for All",  where he discusses unsuccessful attempts by generic drug companies to revive the doctrine.

What I think is really interesting here is the history of the Promise Doctrine. According to Professor Siebrasse, the Promise Doctrine evolved in English law. To paraphrase Siebrasse, in English law "the grant of a patent was an exercise of the royal prerogative, and as such wholly within the discretion of the Crown." Patents thus could be retracted for many reasons, including a false promise of utility, as "measured by the representations made in the patent."  (5-6). This was codified in the English Patent Act until 1977.  (7) ("[T]he English false promise doctrine was codified by a statutory provision that a patent would be void if obtained on the basis of a 'false suggestion.' ”).  

There was an important difference. In the older English cases from which the Canadian Promise Doctrine originated, the elevated promise of utility was actually false or at least misleading. For example, in the 1919 English case, Hatmaker v Joseph Nathan & Co Ltd., the invention claimed a process for producing dried milk. The specification stated that the process would produce milk solids “in a dry but otherwise unaltered condition” and that the reconstituted milk was “of excellent quality.” But it turned out the dried milk was not actually as good as real milk. (8) (citing case). This is why the older English cases referred to a "false" promise. But in the modern Canadian practice, the promise was typically not actually false in hindsight.

Our shared origins in English law means the Promise Doctrine is a path U.S. law could have taken too. It is interesting to ask then: how might a "Promise Doctrine" evolve in U.S. law today? There are a few analogues.

(1) Utility

First, obviously, is Section 101's requirement that a patent be "useful," i.e. the utility requirement. But as is well known, U.S. patent law has an intentionally lax utility requirement. As the Federal Circuit has put it, "[t]he threshold of utility is not high: An invention is "useful" under section 101 if it is capable of providing some identifiable benefit." So making a therapeutic claim like "these compounds are useful in treatment of high blood pressure" would not ordinarily raise red flags unless they are verifiably false or completely incredible, of the "cold fusion" variety.

(2) Duty of Candor/Inequitable Conduct

Second, there is a general prohibition on lying to the Patent Office (e.g. duty of candor, inequitable conduct). If statements about utility are in false and this false claim is "material" in the "but for" sense that the examiner would not have granted the patent unless it believed the assertions, this could potentially make the patent vulnerable to invalidation for inequitable conduct. But merely a premature promise of utility would not be false. And moreover, even a false statement of higher-than-actual utility would not be "material" in most cases, given the currently lax utility standard.

(3) Enablement

Third, closely related to utility is Section 112's "enablement" requirement. Enablement asks, could a person of "ordinary skill in the art" make the invention work in the stated way? But this does not necessarily require assessing the veracity of therapeutic claims. So long as a PHOSITA can practice the invention as claimed without "undue experimentation," it would not strictly matter whether the inventions' therapeutic benefits pan out. For example, it would not matter whether the patients that are treated with a claimed drug live or die. This would be the FDA's concern, not patent courts' and examiners'.

That said, cases like Brenner v. Mason have shown how U.S. law's utility requirement might be beefed up to weed out patents that are filed well before claims of efficacy have been verified. For instance, filing a patent that makes "promises" of therapeutic efficacy when testing has not even been performed in mice might be seen as a premature assertion of utility that warrants invalidation. See Brenner v. Mason, 383 U.S. 519, 534-35 (1966) ("The basic quid pro quo contemplated by the Constitution and the Congress for granting a patent monopoly is the benefit derived by the public from an invention with substantial utility. Unless and until a process is refined and developed to this point—where specific benefit  exists in currently available form—there is insufficient justification for permitting an applicant to engross what may prove to be a broad field.").

But Professor Siebrasse is quick to point out that Brenner's notion of "substantial utility" corresponds to the "scintilla" branch of Canadian utility law, mentioned above, which he says already requires assessing whether the specific asserted benefit of the invention has been developed to the point where it is currently available. The Promise Doctrine, in contrast, is a separate standard that seeks out "promises" and then imposes a higher standard on them.  

***  

I suspect there is more here to uncover on the history of the so-called "promise of the patent" doctrine. I am curious as to why it was not discussed in the Oil States debates, which centered on the conations under which patents can be retracted. I didn't catch it mentioned in the amicus briefs that I read. I checked Professor Oren Bracha's thesis (now book) on U.S. patent law history. He does mention some aspects of this issue his discussion of "working clauses." For example, Bracha states that "working clauses," which required grant holders to practice the invention to which they sought rights,

were a clear manifestation of the two main characteristics of English patents. They expressed the understanding of patents as royal discretionary policy tools, by creating mechanisms for insuring the 'execution' of the specific consideration promised by the patentee as the basis of the patent deal. They reflected the dominant notion of the subject matter of patents as new industries or trades, by focusing on actual putting into practice rather than on mere disclosure of information.   

(Bracha, 20).  But I didn't see anything about invalidations based on a "false promise of the patent" doctrine.