How far does a generic drug maker need to go to exclude liability for inducing patent infringement?
In drug patent cases the product monograph is key in assessing whether inducement exists. In the case of off-label uses, it is customary for a generic drug maker to exclude any references in the innovator’s product monograph that teach the off-label use. How far such edits must go is put in doubt by the Federal Court of Appeal decision in Apotex Inc. v. Janssen Inc., 2023 FCA 220.
The test for a finding of inducing infringement was confirmed by the Federal Court of Appeal as follows:
It is settled law that one who induces or procures another to infringe a patent is guilty of infringement of the patent. A determination of inducement requires the application of a three-prong test.
First, the act of infringement must have been completed by the direct infringer.
Second, the completion of the acts of infringement must be influenced by the acts of the alleged inducer to the point that, without the influence, direct infringement would not take place.
Third, the influence must knowingly be exercised by the inducer, that is, the inducer knows that this influence will result in the completion of the act of infringement. The test is a difficult one to meet.
Canadian Patent No. 2,659,770 claims a combination of the drug macitentan to be taken in combination with a phosphodiesterase type-5 inhibitor (PDE5 inhibitor) to treat a rare disease called pulmonary arterial hypertension (PAH).
There is a previously approved macitentan product called Opsumit. Apotex proposed to sell its version of macitentan for only that indication and not the combination of macitentan with a PDE5 inhibitor.
Apotex carefully scrubbed its version of the product monograph of any reference that would teach the combination of macitentan with a PDE5 inhibitor.
The Federal Court found that was not sufficient. Since Apotex sought approval for the sale of its macitentan as monotherapy for PAH the Federal Court found that a reference to a study in the Apotex PM that both supported macitentan as a monotherapy and also supported the use as a combination treatment with a PDE5 inhibitor was sufficient to find inducement despite no teaching in the PM about the combination treatment.
The Federal Court of Appeal agreed stating:
In my view, the Federal Court made no error of law regarding the second prong of the test for inducing infringement. Moreover, though the Federal Court’s analysis as to how it concluded that the PM would have sufficient influence to satisfy the second prong could have been more fulsome, I am not convinced that the Federal Court made any palpable and overriding error in its consideration and application of the evidence. The Federal Court was clearly convinced that the PM would influence physicians to prescribe combination treatment, even though it does not explicitly mention such treatment. Moreover, because the Federal Court clearly understood the legal test, I infer that it was also convinced that the influence of the PM was sufficient that, without it, direct infringement would not occur. In my view, these conclusions were available to the Federal Court.
The question is how far must a generic drug maker go to avoid patent infringement by inducement. Query if the addition of an express disclaimer would either be permitted by Health Canada in a PM or would overcome the inference that the Court inferred.
 See Apotex Inc. v. Janssen Inc., 2023 FCA 220 at para 4.
 See Corlac Inc. v. Weatherford Canada Ltd., 2011 FCA 228, 95 C.P.R. (4th) 101 at para. 162 citing Dableh v. Ontario Hydro,  3 F.C. 751, paras. 42, 43 (C.A.), leave to appeal refused,  S.C.C.A. No. 441; AB Hassle v. Canada (Minister of National Health and Welfare), 2002 FCA 421, 22 C.P.R. (4th) 1, para. 17 (C.A.), leave to appeal refused,  S.C.C.A. No. 531; MacLennan v. Les Produits Gilbert Inc., 2008 FCA 35, 67 C.P.R. (4th) 161, para. 13.
 See Apotex Inc. v. Janssen Inc., 2023 FCA 220 at para 18.