The Federal Court of Appeal (FCA) recently dismissed an appeal by Apotex from a decision of the Federal Court (see our article here) holding that the claims of Canadian Patent No. 2,527,646 (646 patent) were valid, and prohibiting the Minister of Health from issuing a Notice of Compliance (NOC) to Apotex for its lisdexamfetamine (LDX) product (Shire’s VYVANSE) until the expiry of the 646 patent: Apotex Inc v Shire LLC2021 FCA 52. The prohibition application under the pre-amended Patented Medicines (Notice of Compliance) Regulations was consolidated with Apotex’s action seeking a declaration of invalidity and non-infringement. Apotex appealed both judgments.

Amphetamine was an established treatment for conditions such as Attention Deficit Hyperactivity Disorder (ADHD) but as it is an immediate release compound, it requires patients to take doses frequently throughout the day. LDX is a prodrug of amphetamine that provides sustained release and reduces abuse potential.

Anticipation

The Federal Court judge found the claims at issue were not anticipated by Australian Patent Application No. 54168/65 (AU 168) which discloses a very large class of amino acid conjugates, including LDX. Apotex argued it was an error to consider the advantages of LDX in the anticipation analysis since the 646 patent was not categorized as a selection patent, and that AU 168 necessarily encompasses the compound LDX because, if AU 168 was practiced “across its scope” it would necessarily infringe the 646 patent. The FCA disagreed and affirmed that the validity analysis does not change depending on whether a patent is classified as a selection patent or not; a prior art reference discloses the claimed invention when, if performed, the prior art reference would necessarily result in the infringement of the patent claim. LDX was not an example described in AU 168; it was merely one of a large class of “advantageous compounds”. Accordingly, the FCA held that claims to LDX and its salts in the 646 patent were not specifically disclosed as there are numerous other ways to “perform” AU 168 without necessarily infringing the claims of the 646 patent. 

Obviousness

Apotex also contended the judge erred in not finding the claims at issue obvious. Following a review of the claims and the problem it was intended to solve, the judge had held the inventive concept of the 646 patent was “a sustained release formulation of a therapeutically useful dose of amphetamine that is resistant to abuse”. Apotex argued the judge erred in doing so on the basis that section 28.3 of the Patent Act mandates a narrow, claim-based end point, focussed solely on the “subject matter of the claim” and recourse to the specification is not allowed. It noted that unlike some of the unasserted claims, none of the asserted claims related to sustained release or abuse resistance. The FCA disagreed, holding that section 28.3 does not narrow the inventive concept to the essential elements of the claim itself. Where there is no agreement on the inventive concept, it needs to be construed, and where it is not possible to fully grasp its nature solely from the claims as construed, the judge may have regard to the specification. Here, as the claims to LDX and its salts are to bare chemical compounds, the essential element of each of these claims is the chemical formula itself. Therefore, it is necessary to turn to the specification for amplification. Apotex also argued that the inventive concept was faulty as it made the inventive concept of some of the claims “necessarily redundant”. The FCA again disagreed, holding that while there must be a single overarching inventive concept, each claim can give rise to its own inventive concept, and the inventive concepts of the various claims may overlap or replicate each other. Here, the judge identified the single inventive concept linking each claim of the 646 patent, considered the state of the art, the gap between the state of the art and the inventive concept, and considered whether the differences were obvious based on the enumerated and contextual factors of the obvious to try analysis. There was no reviewable error in the legal framework nor in its application to the facts as found.