Supreme Court Clarifies Standard for Induced Infringement in Hikma v. Amarin

In a unanimous decision handed down today, the Supreme Court delivered a tactical victory for Hikma, and a measure of guidance for other generic manufacturers. In Hikma Pharmaceuticals USA Inc. v. Amarin Pharma, Inc., No. 24-889, the Court held that drug manufacturer Amarin, the reference product sponsor, failed to state a claim for active inducement of patent infringement under 35 U.S.C. § 271(b). 

The ruling makes clear that "skinny label" generic drug manufacturers do not induce infringement by simply complying with industry practice and equating the generic drug to the reference drug.

A reference drug manufacturer must demonstrate that a generic drug manufacturer actively encouraged or instructed infringing use.

The Drug, Labels, and Lawsuit

The dispute centers on icosapent ethyl, marketed by Amarin under the brand name Vascepa. In 2012, the FDA approved Vascepa to treat severe hypertriglyceridemia (the "SH indication"). Seven years later, the FDA granted a second, far more commercially significant approval: reducing cardiovascular risk in hypertriglyceridemia patients already taking statins (the "CV indication"). Amarin obtained two method-of-use patents covering the CV indication.

Hikma, a generic drug manufacturer, filed an abbreviated new drug application (ANDA) for generic icosapent ethyl. After a district court invalidated Amarin's SH-indication patents, Hikma pursued a "skinny label" limited to the unpatented SH indication and carving out Amarin's still-patented CV indication. The FDA approved Hikma's application in 2020 and assigned the generic drug an "AB" rating, indicating therapeutic equivalence to Vascepa when used according to its labeling. 

Amarin filed suit in the District of Delaware, alleging that Hikma actively induced others to infringe the CV-indication patents. According to the Supreme Court, induced infringement under § 271(b) requires three elements: 

1. direct infringement by a third party,
2. knowledge that “the induced acts constitute patent infringement,” and
3. “active steps to encourage direct infringement.”

This suit centered on the third element, “active steps.” Amarin argued that the "totality" of Hikma's statements—across the skinny label itself, a patient information leaflet, Hikma's website, and its press releases—encouraged infringement.

The District Court granted Hikma's motion to dismiss for failure to state a claim, concluding that none of the statements constituted active steps to encourage infringement. The Federal Circuit reversed, finding it "at least plausible that a physician could read" the statements "as instruction or encouragement to" infringe. The Supreme Court granted certiorari to resolve whether Hikma's various statements, taken together, satisfied Rule 12(b)(6). 

The Legal Framework: The “Plausibility” Standard and Motions to Dismiss

Motions to dismiss under Rule 12(b)(6) are controlled by the plausibility standard articulated in Bell Atlantic Corp. v. Twombly, requiring a plaintiff to plead facts that, if true, “allo[w] the court to draw the reasonable inference that the defendant is liable for the misconduct alleged,” and rule out “obvious alternative explanation[s] for the defendant’s conduct.” The arguments presented by Hikma and Amarin reflected a divergence on the question of what, under Twombly, had to be plausible: that Hikma’s statements actively encouraged infringement, or that doctors might understand the statements as instructions to infringe?

The Court's Analysis: "Active Steps" Required to Induce Infringement 

Writing for a unanimous Court, Justice Jackson set out by resolving the procedural issue underlying the dispute: the relevant inquiry under Twombly was whether Amarin plausibly alleged that Hikma actively encouraged infringing use.

Proceeding under the correct legal standard, the Court emphasized that induced infringement requires "purposeful, culpable expression and conduct"—affirmative actions designed to bring about patent infringement, not merely passive conduct that might lead to it. Overturning the Federal Circuit’s GSK v. Teva opinion, the Court expressly rejected what it described as the recent trend in Federal Circuit case law that focused on whether statements could be read by medical providers as instructions to infringe. 

The Court noted that “[a]ll 50 states and the District of Columbia permit (or require) medical providers to substitute the brand-name drug with the cheaper generic version.” The existence of these provisions means that “generic manufacturers surely know (and perhaps even expect) that their products will be put to infringing use.” But “mere knowledge of infringing potential or of actual infringing uses [is] not . . . enough . . .to subject a distributor to liability.” 

With this framework in hand, the Court proceeded with a three-pronged analysis.

Prong One: Compliance with Law and Industry Practice. The Court found that several of Hikma's allegedly inducing statements had an "obvious alternative explanation": Hikma was simply complying with the law or following standard industry practice. The skinny label retained information about a clinical study involving statin-taking patients, but that was because federal law requires the generic label to be identical to the reference product’s label except for the carved-out patented use. Likewise, describing the product as "'generic Vascepa'" or the "'generic equivalent'" was nothing more than "normal industry practice." The Court declined to "put generic manufacturers between a rock and a hard place by turning adherence to the law and industry standards into building blocks for illegal conduct." 

Prong Two: Omissions Are Not Active Steps. The Court held that Amarin could not rely on "mere omissions, inactions, or nonfeasance" to support an active inducement claim. Amarin had pointed to the skinny label's omission of the CV Limitation of Use and the press releases' failure to mention that Hikma's approved use was limited to the "far-lesser-known SH indication." But the Court reasoned that inferring inducement from such omissions would mean that "ordinary merchants could become liable for any misuse of their goods and services, no matter how attenuated their relationship with the wrongdoer." 

Prong Three: Vague Statements Plus Speculation. Finally, the Court found the remaining allegations—the patient information leaflet's warning about cardiovascular side effects, the website's listing of the therapeutic category as "hypertriglyceridemia" and the "AB" rating, and the press releases' inclusion of sales figures—"too vague" to support inducement liability. The patient leaflet's warning and disclaimer were "implausibly roundabout ways to induce medical providers to infringe." The website's therapeutic category designation was "generally akin to describing a drug for leukemia as a 'cancer drug'"—a broad category, not an instruction to prescribe for a patented use. And the sales figures in the press releases—directed at investors, not doctors—required a "possib[le]" but not "'plausible'" chain of events for a provider to draw encouragement to infringe. 

Notably, however, the Court did not adopt Hikma's most aggressive position. Justice Jackson clarified that inducement need not be "express"—implicit encouragement can suffice, as it did in Grokster, where StreamCast used the suggestive name "OpenNap" for its file-sharing program. But whether implicit or explicit, the inducement must be "clear" to the relevant audience and "affirmative."

Key Takeaways

“Plausibility” requires stronger facts. By holding that compliance with labeling requirements, standard industry terminology, and omission of patented indications cannot collectively give rise to inducement liability, the Court has provided a measure of guidance to generic drug manufacturers operating under skinny labels. Uncertainty remains, however, as to what facts would meet the Twombly plausibility standard, a question that may be addressed by Amarin upon remand.

Active inducement requires intentional encouragement. Going forward, plaintiffs alleging induced infringement in the Hatch-Waxman, and potentially other, contexts will need to show that the defendant designed its statements to encourage infringement—not merely that a physician could interpret them that way. 

Requires affirmative statements. Omissions will not do. The holding that omissions and nonfeasance cannot constitute "active steps" under § 271(b) is a significant doctrinal clarification. Reference product sponsors will likely no longer be able to build inducement claims on a generic's failure to affirmatively disclaim patented uses.

The "totality" theory has limits. Amarin urged the Court to view its allegations holistically, arguing that the cumulative effect of Hikma's statements supported an inference of inducement. The Court was unpersuaded, finding that the allegations, "whether viewed together or separately, fail to establish that Hikma took any affirmative steps to encourage infringement." This is an important signal that aggregating individually insufficient allegations may not salvage an otherwise weak inducement claim.

The door is not completely shut. The Court left open the possibility that a generic drug manufacturer could cross the line into inducement liability through implicit but "clear" and "affirmative" encouragement. Future litigation will likely test where that line falls—particularly in cases where a generic drug manufacturer’s marketing materials go beyond mere compliance with labeling requirements and industry norms.

Hikma Pharmaceuticals USA Inc. v. Amarin Pharma, Inc., No. 24-889, 608 U.S. ___ (June 4, 2026)

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