Federal Court Upholds Patent Validity And Grants Prohibition Order Against Generic Lisdexamfetamine In Pre-CETA PM(NOC) Application

The Federal Court dismissed Apotex's action to invalidate the claims of Canadian Patent No. 2,527,646 (the 646 Patent), which was consolidated with Shire's application to prohibit the Minister of Health from issuing a Notice of Compliance for Apotex's generic version of VYVANSE® (lisdexamfetamine). Shire's counterclaim for infringement in the action was dismissed but the Court granted the prohibition order against the Minister.

Patent found to be valid

Amphetamines are used to treat attention deficit and hyperactivity disorder (ADHD), but are controlled substances because they can be abused for their euphoric effect. Abuse typically occurs when tablets are crushed into a powder that is snorted or dissolved and injected. Sustained-release formulations improve convenience for patients but are more susceptible to abuse because they contained greater amounts of amphetamines.

Invention of the 646 Patent

The 646 Patent claimed prodrugs of amphetamines and derivatives or analogs formed by covalent attachments of chemical moieties to the amphetamine. These prodrugs are converted in the body to the active amphetamine over time, providing sustained release of amphetamine while reducing abuse potential. The asserted claims of the 646 Patent covered lisdexamfetamine (LDX), consisting of d-amphetamine conjugated to the amino acid L-lysine. The claims at issue also cover certain salts of LDX, pharmaceutical compositions containing LDX, and use of LDX to treat ADHD.

Not a selection patent

Shire argued that LDX is selected from the class of amphetamine amino acid conjugates encompassed by Australian Patent No. 54168/65 (the AU 168 Patent). Apotex disagreed. Justice Fothergill doubted that the 646 Patent may be properly characterized as a selection patent. However, he found that nothing turned on this point because the outcome of his anticipation and obviousness analyses were not affected by it. In coming to his conclusion, he distinguished and rejected Apotex's reliance on Hoffmann-La Roche Ltd. v Apotex Inc., 2013 FC 718, noting that there may be reason to approach this decision with caution.

Not anticipated

The Court held that the 646 Patent was not anticipated. Justice Fothergill found that the expert evidence raised many unanswered questions regarding the prior art, which did not clearly relate to prodrugs, did not disclose the process of making LDX, and did not teach that the compounds it disclosed provide a sustained release treatment for ADHD with...