Last Wednesday, April 29, the Supreme Court of the United States (SCOTUS) heard oral arguments in Hikma Pharmaceuticals USA Inc. v. Amarin Inc. (docket no. 24-889), a case on induced infringement liability for “skinny label” generic drugs. The case raises important questions for generic drug manufacturers: when marketing under a skinny label, can public statements referencing the brand drug lead to liability for induced infringement?
Below are some views of this issue from a cross-border US/Canadian perspective.
During oral arguments, SCOTUS Justices asked numerous questions from the bench, giving some insight into their thinking. At least some of the Justices seem inclined to rule in favour of the generic manufacturer, Hikma.
In Canada, meanwhile, courts may be moving the other way. In several cases in the last few years, generics referencing the brand drug were found to induce infringement even without explicitly promoting a patented use – a theory that SCOTUS might be ready to reject. With Canadian and US law potentially diverging, a generic-friendly decision in Hikma could provide compelling rationale for the future trajectory of Canada’s induced infringement framework.
What happened in Hikma?
The drug: Amarin’s Vascepa® (icosapent ethyl) is approved by the FDA for two indications: severe hypertriglyceridemia (SH) and cardiovascular risk reduction (CV). Only the CV indication is patented, and it is the more commercially valuable use. Hikma launched its generic icosapent ethyl under a skinny label, obtaining approval for only the SH indication, with a “section viii carveout” omitting the patented CV indication.
Amarin’s allegations: Amarin based its complaint on: (1) Hikma’s label (Hikma failed to include any limitation of use against the CV indication, and included side effect warnings for cardiovascular patients), (2) marketing materials that describe Hikma’s product as being a “generic version” of Vascepa, and (3) Hikma’s website referencing the commercial value of Vascepa sales.
Procedural background: The District Court of Delaware dismissed Amarin’s complaint on the pleadings as failing to disclose a viable claim for inducement. The Court of Appeals for the Federal Circuit reversed, holding that Hikma’s skinny label, taken together with its marketing materials, could plausibly support Amarin’s claim for induced infringement. Hikma appealed to the SCOTUS.
The arguments in Hikma
SCOTUS was faced with a central question: when a generic launches under a skinny label, does calling the drug a “generic version” and publicly referring to the totality of the brand’s sales plausibly present a case for induced infringement? The parties agreed that labelling alone cannot induce infringement, however, they disagreed on what further conduct would attract liability.
Hikma’s position: Hikma argued that liability for inducement requires “active” and “affirmative” conduct encouraging infringement; passive marketing and labelling fall short of this standard. Because the FDA requires that generics prove interchangeability in their ANDA, Hikma’s FDA-approved label closely tracks Vascepa’s label.
According to Hikma, its public statements calling its product a “generic version” of Vascepa (or about Vascepa more generally) are simply a downstream function of the drug approval framework, not evidence of inducement. Hikma further maintained that the law does not require generics to actively discourage off-label prescribing, especially under a regime that expressly permits skinny-labelled generics.
Amarin’s position: Amarin contended that inducement is contextual. According to Amarin, Vascepa has become synonymous with treating CV risk, thus Hikma’s public statements naturally function as advertising the patented indication – a “textbook case” of inducement. Amarin pointed out that seven other manufacturers market generic icosapent ethyl under skinny labels, but Amarin has not sued those generics because they did not advertise the patented CV indication. Amarin also argues that Hikma could and should have included a limitation of use statement in its label.
Amicus briefs: More than 20 amicus curiae, including industry organizations on behalf of both patentees and generics, academics, and politicians, filed briefs with the Court. Interestingly, former Senator Waxman, who pioneered the Hatch-Waxman patent linkage framework, filed a brief in support of Hikma, which the Court explicitly raised in questions to counsel. Senator Waxman argued that Amarin’s theory of inducement is inconsistent with the Hatch-Waxman framework, and that any reliance on Hikma’s label, and its public comparisons to Vascepa, is misplaced. Senator Waxman contended that accepting Amarin’s position would perversely incentivize brand companies to develop labels to track anticipated infringement cases against generics which would “threaten to undermine the generic pharmaceutical industry”.
SCOTUS hearing: Many of the questions from the bench challenged Amarin’s counsel on their interpretation of the existing standard for induced infringement, which had the potential of lowering the bar for inducement liability. The Justices also appeared skeptical of the submissions that Hikma’s impleaded conduct met the existing “active encouragement” threshold.
SCOTUS reserved judgment following oral arguments, as expected. A decision is likely to be issued within the year. The decision is being closely watched by the entire pharmaceutical industry for its potential implications on the effective scope of pharmaceutical use patents.
Inducement liability in Canada via generic product labeling
In contrast to the US, recent Canadian court decisions have potentially expanded generic exposure to induced infringement. In these cases, courts have held that passive statements, or even labelling alone, could meet the requisite standard for inducement.
Macitentan: In Apotex v Janssen, 2023 FCA 220, the Federal Court of Appeal upheld an inducement finding despite a generic monograph that carved out the patented combination use entirely. The Court relied on extrinsic evidence – including a well-known pivotal clinical trial referenced in Apotex’s generic monograph – to find that physicians would prescribe generic macitentan according to the patented combination regimen. Notably, the FCA held that explicit instruction and intention are not required to establish the “influence” required for induced infringement, cutting against earlier authority requiring that the product monograph affirmatively direct prescribers to the patented use.
Paliperidone: In a series of generic paliperidone cases (Teva v Janssen, 2023 FCA 68, Apotex v Janssen, 2024 FCA 9, and Pharmascience v Janssen, 2024 FCA 10), which were not skinny labels per se, and instead involved labels that covered both patented and unpatented indications relating to dosing intervals, the FCA indicated that affirmative encouragement by a generic is not required.
The Court held that it was enough for inducement that a generic monograph includes a patented regimen among the range of possible (unpatented) uses, even if the label does not directly point prescribers to the patented use.
Previous case law had held that the inducer must have done something to cause the direct infringer to infringe, and that offering a potentially infringing drug for sale is not enough. It seems that the courts have, in effect, moved away from a true “but for” causation standard in favour of a more passive theory of inducement. The Supreme Court of Canada (in Apotex and Pharmascience) refused leave to appeal these decisions in 2025.
Takeaways
Recent Canadian appellate decisions describe an inducement doctrine that does considerably more work for patentees than it used to. Canada has seemingly moved away from “active” inducement to a passive ‘liability by labelling’ standard that is inconsistent with inducement doctrine in the US. Indeed, both parties in the Amarin case agreed that labelling alone cannot attract inducement liability; whereas Canadian courts have repeatedly held that it can.
For Canadian generics, neither a clean carveout of a patented use, nor a label targeting unpatented use, offers guaranteed protection against inducement. A generic-friendly inducement ruling in the US will not on its own reshape Canadian inducement risk. But it might give Canadian generics compelling logic worth pressing.