Canada’s Intellectual Property Firm

Orders of prohibition relating to polymorphic form patent for PRISTIQ upheld on appeal

Authored byBrandon Heard

As previously reported, the Federal Court, in a pair of decisions, granted orders prohibiting Apotex and Teva from marketing their generic o-desmethyl-venlafaxine (ODV) succinate products (Pfizer’s PRISTIQ) until expiry of Patent No.  2,436,668 (668 Patent). On January 25, 2019, the Federal Court of Appeal (FCA) dismissed both Apotex’s and Teva’s appeals: Teva v Pfizer, 2019 FCA 15; Apotex v Pfizer, 2019 FCA 16.

The 668 Patent relates to a novel crystal form of a particular salt of ODV: Form I ODV succinate. Obviousness was the only issue in the Teva appeal. Obviousness and anticipation were at issue in the Apotex appeal.


(i) Application judge did not err in applying the test for obviousness

Both Apotex and Teva argued that the application judge misapplied the test for obviousness. The FCA disagreed, observing that the judge used the four-step inquiry provided by the Supreme Court in Apotex v Sanofi-Synthelabo, 2008 SCC 61 (Sanofi). In applying the test, the application judge addressed both “obvious to try” and recent guidance from the FCA in Bristol-Myers Squibb Canada v Teva, 2017 FCA 76 (Atazanavir).

In view of this conclusion, the FCA emphasized that “absent any palpable and overriding error by the Federal Court Judge, this Court ought not to interfere with his findings of fact or mixed fact and law.” The application judge is entitled to deference in weighing the evidence.

(ii) Application judge did not err in distinguishing recent FCA decisions

Both Apotex and Teva argued that the application judge erred in declining to follow Atazanavir and Pfizer v Ratiopharm, 2010 FCA 204 (Amlodipine). Apotex elaborated, asserting that the present case involves salts, not crystal formation, and should be interpreted consistently with Atazanavir, Amlodipine and other “salt cases”. The FCA disagreed. The present case was distinguishable on the basis that (a) the inventive concept was a novel crystalline form (not a salt), (b) there was no motivation to prepare ODV succinate, and (c) “it was not predictable whether Form I ODV succinate could be prepared at all”. Moreover, Apotex’s own witness “confirmed that crystal structures are not predictable”.

(iii) Application judge did not err in discussing properties of the novel crystal form

The parties agreed that “the inventive concept or the solution taught by the ‘668 Patent is the novel crystal Form I ODV succinate”, and does not include properties of the compound. Both Apotex and Teva argued that the trial judge improperly relied on the fact that properties of Form I ODV succinate were unpredictable in finding the invention non-obvious.

Though the application judge discussed properties of Form I ODV succinate, the unpredictability of these properties was not the basis for his conclusion of non-obviousness. “Rather, the Federal Court Judge relied on evidence that demonstrated that a skilled person could not have known or predicted that the Form I ODV succinate – i.e., the crystal form itself – could be made or even existed.” Moreover, the Sanofi approach is a “flexible, contextual, expansive and fact driven inquiry” permitting the application judge to discuss properties as he did.

(iv) Application judge did not err in considering course of conduct

Apotex and Teva argued that the application judge erred in considering several aspects of the inventors’ course of conduct. The FCA disagreed.

First, Teva argued that difficulties experienced by Pfizer with ODV fumarate – a different salt of ODV – would not have been known to the skilled person and thus should not have been factored into the analysis of the amount of effort required to obtain the invention. This argument was rejected as Sanofi “expressly permits consideration of the course of conduct of those involved in the claimed invention including the inventor and his or her team”.

Second, Apotex argued that Wyeth’s (Pfizer’s predecessor) failed efforts “in other directions” – including work relating to ODV fumarate and an ODV prodrug – were not relevant to the invention story. The FCA disagreed; per Sanofi: “time, money and effort … expended in research looking for the result the invention ultimately provided before the inventor turned or was instructed to turn to search for the invention” may be considered as part of the inventors’ course of conduct.

Third, Apotex argued that work conducted after Wyeth had prepared and identified Form I ODV succinate – considered by the application judge – was irrelevant. The FCA concluded that the application judge did not err in considering these efforts. This “extensive” research – a polymorph screen conducted by a contractor – was a “continuation” of the patentee’s work and “required in order to conclude that Form I ODV succinate was the most stable hydrated form.” Prior to the contractor’s work, the patentee did not know what it had; “the new crystal form still needed to be characterized.”

(v) Evidence alleged to be hearsay was not determinative

Teva argued that evidence that individuals at Wyeth were skeptical that the difficulties with ODV succinate could be overcome by another salt (e.g. ODV succinate) was hearsay. The FCA determined that this evidence was “neither determinative nor decisive”. Even if this evidence were excluded, the application judge’s other findings support his conclusion of non-obviousness.


To establish anticipation, Apotex relied on expert evidence addressing obviousness, which was rejected by the application judge. The FCA found that, even if accepted, Apotex’s evidence would not have established anticipation. The application judge considered “the only piece of the prior art that could possibly have disclosed the invention”, and found that it “did not disclose the Form I ODV succinate”.

If Apotex and Teva wish to appeal the decisions, they will need to seek and obtain leave from the Supreme Court of Canada.

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