Selection Patent for Apixaban Upheld by Federal Court of Appeal

Selection Patent for Apixaban Upheld by Federal Court of Appeal

A thermometer is shown on a pile of pharmaceutical pills.

Pharmascience Inc. v. Bristol-Myers Squibb Canada Co. 2022 FCA 142

In a notable, recent Federal Court of Appeal (FCA) decision, Justice Locke upheld the Federal Court’s ruling that validity analyses as they relate to selection patents follow the same validity analyses as regular utility patents, regardless of their status as a selection patent. In his reasons, Justice Locke also further addressed the issue of insufficiency based on issue date versus claim or publication date of a selection patent.

Background

The patents in suit, namely Canadian Patent Nos. 2,461,202 (the 202 Patent) and 2,791,171 (the 171 Patent) concerned an anticoagulant product for treating thrombosis marked by the Respondnent, Bristol-Myers Squibb (BMS) as Eliquis, with the main pharmaceutical ingredient of Eliquis being apixaban. Apixaban is a selective inhibitor of the enzyme Factor Xa (FXa). The selection patent issues are directed to the 202 Patent in particular. The 202 Patent’s claims are directed to apixaban itself, and to its use in the treatment of thromboembolic disorders.

Analysis

The Status of the 202 Patent as a Selection Patent

The appellant, Pharmascience Inc. (PMS) argued that, since apixaban falls within the scope of the compounds already disclosed by other patents held by BMS (namely, Canadian Patent 2,349,330 (the 330 Patent)), the disputed claims of the 202 Patent relating to apixaban can be valid only if it is an inventive selection over the 330 Patent.[1] PMS argues that the fact that the Federal Court did not make a clear assertion that the 202 Patent is a selection patent, as well as the fact that the Federal Court did not indicate a special advantage of the 202 Patent over the 330 Patent, reflects a lack of understanding of the 202 Patent.

In his reasoning, Justice Locke disagreed with PMS’ arguments, asserting that the Federal Court clearly indicated that the requirements for a selection patent were in fact met, and the 202 Patent does disclose special advantages of apixaban. The Federal Court’s reasons stated that “a skilled person reading the 202 Patent “would understand that apixaban was singled out from the genus of compounds [disclosed in the 330 Patent] because, while the genus had the potential to be useful in treating thromboembolic disorders, apixaban was selected in the 202 Patent because it was useful.””[2] PMS criticized this finding of the Federal Court, asserting that the Federal Court only focused on apixaban simply having been singled out in the 202 Patent’s claims, rather than having any special advantage over the claims of the 330 Patent.

The FCA disagreed with PMS’ assertion, finding that the 202 Patent gave the public something useful it did not have with the 330 Patent, specifically that it is an FXa inhibitor that is effective as a treatment for thromboembolic disorders,[3] which was not claimed in the 330 Patent, and for this reason, the 220 Patent maintains it’s status as a selection patent.

Insufficiency of the 202 Patent

PMS had also strongly argued that since it was not indicated that the focus of the invention was apixaban neither on the date that the 202 Patent application had been filed or on the date it was published, then the 202 Patent is insufficient under paragraph 27(3)(a) of the Patent Act which states that a patent specification must “correctly and fully describe the invention and it’s operation or use as contemplated by the inventor.”[4]

The 202 Patent application as filed and published, described a large number of compounds, of which apixaban was among. The claims focusing on apixaban were introduced years later, shortly before the 202 Patent was issued. PMS argued that 202 Patent is invalid because the date for determining sufficiency is the publication date, relying on a discussion by Justice Roger T. Hughes in Novartis Pharmaceuticals Canada Inc. v. Teva Canada Limited, 2013 FC 283, (Zoledronate), in which Justice Hughes expressed a preference for the publication date on the basis that “that is the date that the person applying the patent has committed to claims for the invention in a manner available to the public.”[5] Justice Locke, however, noted that the discussion in  Zoledronate concerning the date for sufficiency was obiter dicta, and that many Federal Court cases have commented on the question of the relevant date for determining patent sufficiency, such as Merck & Co. v. Apotex Inc., [1994] F.C.J. No. 1998 (QL), 59 C.P.R. (3d) 133 (F.C.T.D.), where some of the same Canadian authorities as the Zoledronate were reviewed; however the Federal Court in that case concluded that it was the patent specification at date of issuance that was of relevance.[6]

Notably, Justice Hughes went on to note that both cases cited a passage from the Supreme Court of Canada in Pioneer Hi-Bred Ltd. v. Canada (Commissioner of Patents), [1989] 1 S.C.R. 1623, 25 C.P.R. (3d) 257, which states that a patentee must meet their side of the patent bargain by providing a specification that permits a skilled person, after the expiration of the patent, “to use the invention as successfully as the inventor could at the time of his application.”[7]

Continuing on with his reasons, Justice Hughes noted that the real issue is whether the addition of the claims specific to apixaban introduced new matter to the 202 Patent specification that could not be reasonably inferred from the application as filed. Justice Hughes stated that the existence of the description of apixaban and how to make it, would seem sufficient enough to support the introduction of the claims directed to apixaban, despite the broad range of compounds originally claimed.[8] Additionally, there is no specific requirement for a selection patent to discuss the special advantages of the selection over the genus in any particular way, as noted in the discussion regarding the status of the 202 Patent as a selection patent. What is necessary for sufficiency to be fulfilled is a description of the invention and a definition of the way it is built or produced. Justice Hughes concurred with the finding of the Federal Court that these requirements were met by the 202 Patent in regard to the apixaban claims, and that there was no error of law or fact that would permit the FCA to interfere with the finding. As such, the 202 Patent specification could not be invalidated on the basis of insufficiency.

Commentary

While this case swayed in favor of the Patentee in the finding that the 202 Patent specification was sufficient regardless of the contents of the specification on the filing date versus the claim date, it is always important to ensure that upon filing, the patent application is as enabling and sufficiently detailed as possible with regards to the claim scope protection sought by the Patentee. Although the specification may be amended during prosecution, to avoid any possibility of invalidation of a patent based on insufficiency at filing date, best practices include vigilance to ensure that the application adheres to the “Patent Bargain” theory, in which the Patentee must uphold their side of the bargain to provide a sufficient and fully-enabling disclosure that supports the claims completely and enables a person of skill to use the invention.

Please contact a patent professional at PCK Intellectual Property to learn more about drafting applications for pharmaceutical patents.


Footnotes

[1] Pharmascience Inc. v. Bristol-Myers Squibb Canada Co. 2022 FCA 142, para 11.

[2] Pharmascience Inc., para 12.

[3] Pharmascience Inc., para 15.

[4] Patent Act, RSC 1985, c P-4, section 27(3)(a).

[5] Novartis Pharmaceuticals Canada Inc. v. Teva Canada Limited, 2013 FC 283, para 179.

[6] Merck & Co. v. Apotex Inc., [1994] F.C.J. No. 1998 (QL), 59 C.P.R. (3d) 133 (F.C.T.D.),  para 120.

[7] Pharmascience Inc., para 30.

[8]Pharmascience Inc., para 37.

 


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A thermometer is shown on a pile of pharmaceutical pills.