Tuesday, April 9, 2013

Relevant Date for Assessing Sufficiency of Disclosure

Tuesday, April 09, 2013
relevant date for assessing sufficiency of disclosure
Last month the Federal Court released a decision relating to an application brought by Novartis Pharmaceutical Canada Inc. (Novartis) under the provisions of the Patented Medicines (Notice of Compliance) Regulations (the PM(NOC) Regulations) to prohibit the issuance of a Notice of Compliance to Teva Canada Limited (Teva) for its zoledronic acid IV infusion, a potent bone resorption inhibitor useful in treatment of osteoporosis, until the expiry of Canadian Patent Nos. 1,338,895 (‘895 Patent) and 1,338,937 (‘937 patent). 

Both the patents in question are “Old” or pre-1989 Act patents. Unlike post-1989 patents which are published 18 months after the first priority date, “Old” Act cases are not published until issuance. The ‘895 Patent issued and was therefore published February 4, 1997 (over 10 years after its priority date). The ‘937 Patent issued and was therefore published February 25, 1997 (again over 10 years after its priority date).

The key issues addressed in this decision was the invalidity of the ‘895 and ‘937 Patents on the basis of obviousness, inutility and insufficiency. 

At issue was Claim 14 of ‘895 patent, which is directed to a large genus of compounds (including zoledronate within its scope) and two claims of the ‘937 patent, one directed to the zoledronate itself and the other directed a pharmaceutical composition containing zoledronate, both of which were at issue.


The question of obviousness was assessed using the four-step guide established by the Supreme Court of Canada in Apotex Inc. v. Sanofi-Synthelabo Canada Inc [Sanofi]

In identifying the inventive concept of the claims at issue, the guidelines provided in a recent Federal Court decision in AstraZeneca Canada Inc v Teva Canada Limited, 2013 FC 245 was also considered, which stipulated that “the entire specification, including the claims, must be considered in determining the nature of the invention”, and that the question of obviousness be determined by reference to the claim and not to vague paraphrase based on the extent of the description. 

The court held that the inventive concept of the ‘895 patent was: 
a family of (about 1.2 million members) novel compounds containing a 5-membered ring, which is connected to the geminal BP carbon by a one-carbon linker (―CH2―). These BP’s have biological activity as calcium complex formers and inhibit bone resorption. ([paragraph 119]) 
The court also held that despite the discussion of a large number of compounds in the description of the ‘937 patent, the inventive concept of the claims of the ‘937 patent (directed to single compound) was that:
zoledronate is a useful inhibitor of bone resorption in rats and that, as such, is suitable for use as a medicament in the treatment of diseases in humans associated with impairment of calcium metabolism. ([paragraph 125]) 
During assessment of the difference between the prior art and the inventive concepts of the two patents, although the Court noted that it was previously known that a class of bispohosphonate compounds can be useful in controlling bone resorption, the Court held that:
even given a broad number of choices for atoms or molecules or compounds that could be attached, even using one carbon linker, to the geminal carbon backbone of a bisphosphonate, there is still too much uncertainty as to whether any particular combination will be useful. (see paragraph [154]) 
The Court thus concluded that it would not be “more or less evident” that the class of compounds claimed in claim 14 of the ‘895 patent or zoledrone as claimed in the ‘937 patent ought to work as of their respective dates of invention. Accordingly, the allegations of obviousness were found to be not justified. 


The question of utility was assessed from the point of whether the utility was demonstrated or soundly predicted for the full scope of the claims at the Canadian filing date, as required by Canadian Patent Law.

The inventors of the ‘897 patent tested one compound of the 1.2 million compounds falling within the scope of the genus of claim 14 before the priority date of the application, and made and tested zoledrone before the filing date of the patent. The court held that testing of two compounds does not “establish that the class of 1.2 million compounds embraced by claim 14 had utility”. (paragraph [167]). The Court further stated that:
there is nothing in the description of the '859 patent that any witness said would establish a basis for sound prediction that all members of that class would have utility. In brief, the state of the art was at the empirical stage where compounds would have to be assessed individually. There was no consensus in the state of the art at the time that there was a basis for drawing conclusions as to a class. 
The Court thus concluded that the utility of the entire class of 1.2 million compounds of claim 14 has not been demonstrated or soundly predicted as of Canadian filing date of the ‘897 patent, and therefore the allegation of lack of utility was found to be justified. 

With respect to the ‘937 patent, the Court held that in view of the testing of the claimed compound before the Canadian filing date, which found it to be useful for the stated purpose, the allegation of lack of utility is not justified. 


In assessing the sufficiency of disclosures of the two patents at issue, the Court first established the relevant date for considering the sufficiency, which was main point of contention between the Parties, as the patents were filed under “Old” Act. Teva’s position was that the date of consideration should be “the filing date”, whereas Novartis asserts that it should be “the date of publication”, which in the present case is the date when the patents were granted. The difference in the two dates is about 9 years. 

The Court specifically stated that “most appropriate date for consideration of sufficiency of a Canadian patent is the “date of publication”, which for an “Old” Act patent is the date of issuance and for a “New” Act patent “the date of publication”. Although I understand the rational of the Court, I can’t help but think of the “Old” Act case that I am aware that was pending for over 25 years. Significant advancement in a field can occur during the pendency of an “Old” Act case. Specifications which would have originally have been found to be insufficient could presumably be found to be sufficient because of significant advancement in a particular field. 

As laid out previously in Consolboard and Pioneer Hi-Bred and in Supreme Court case relating to Viagra, the Court affirmed that for disclosure to be sufficient, “it must enable a person skilled in the art, having only the disclosure, to put the invention into practice”. 

The Court held that for the same reasons as discussed with respect to utility, claim 14 of the ‘895 patent is insufficient, and did not pursue this question further. 

With respect to the ‘937 patent, the Court held that the requirements of “sufficiency of patent disclosure” are met at the date of issuance of the patent. 

Although the description of the ‘937 patent described a number of compounds as being preferred, most preferred, and made a statement at page 7 that the invention relates specifically to some 32 compounds found in the Examples, zoledronate being one of them, but not specifically mentioned in this description, the Court distinguished this case from the Supreme Court’s recent decision relating to Viagra, as the claims of this patent were specific to zoledronate only. 

The Court also noted that the application for the ‘937 patent, as originally filed (at its priority date), contained claims to many compounds, including genus claims and claims to specific compounds, including, but not restricted to zoledronate. Zoledronate was made and tested between the priority date and the filing date of the application, and the data in the patent was found to be different than that of the priority document.  

The Court held that if the sufficiency was assessed at the filing date of the application for the ‘937 patent, the Court would have found that the application was no different than that considered by the Supreme Court in recent Viagra Case, and thus invalid for lack of sufficient disclosure. 

Link to Decision: