Amarin v. Hikma: Defining the limits of protection that skinny labels afford

On August 22, 2024, Hikma Pharmaceuticals USA Inc. and Hikma Pharmaceuticals, PLC (collectively Hikma), filed a petition for rehearing en banc, asking the US Court of Appeals for the Federal Circuit to reconsider its recent decision on induced infringement by generic drug companies that use a “skinny label.” Amarin Pharma, Inc. v. Hikma Pharmaceuticals USA Inc., No. 2023-1169 (Fed. Cir. 2024). The Amarin decision is the Federal Circuit’s latest attempt to grapple with the issue of skinny labels, and it explores the interplay between a generic’s reliance on a skinny label, and liability for induced patent infringement.

How “skinny labels” work

Generic applicants may apply for skinny labels, also known as section viii carveouts, in instances when some, but not all, of a prescription drug’s indications have patent protection. A generic applicant pursuing a section viii carveout removes the patent protected indication from its proposed label submitted to the Food and Drug Administration (FDA). FDA may then grant approval for the remaining indications in the proposed label. Generic applicants typically pursue skinny labels where the expiration dates of patent rights covering different indications are staggered – an expired set of patent rights on one indication allows the generic to obtain approval for that indication, while the patent-holder retains exclusive rights to the remaining “carved out” indications. With the patented indications removed, the skinny label may be used to avoid claims of induced infringement – but they are not impenetrable shields. Holders of skinny labels can still be liable for infringing patents that cover their products’ non-approved indications.

The Amarin v. Hikma Federal Circuit decision

The Federal Circuit’s Amarin decision describes certain behavior by holders of skinny labels that, when taken together, may lead to a finding of induced infringement.

The case involves Amarin’s VASCEPA® (icosapent ethyl) product. In 2012, FDA approved VASCEPA® for severe hypertriglyceridemia (SH indication). In 2019 FDA approved VASCEPA® for a second indication – the reduction of cardiovascular risk (CV indication). The approval for the CV indication also allowed Amarin to remove a Limitation of Use concerning cardiovascular effects from its label.

In the intervening years between FDA’s approval of the first and second indications, a court found Amarin’s patents related to the SH indication to be invalid. In other words, Amarin only had patent protection for the CV indication. Hikma, which had already filed an ANDA against VASCEPA®, subsequently filed a section viii statement to carve out the CV indication from its label. In 2020, FDA approved Hikma’s skinny label for generic icosapent ethyl for the treatment of severe hypertriglyceridemia only. Like Amarin’s VASCEPA® label, Hikma’s generic label did not contain a cardiovascular Limitation of Use.

After FDA granted approval, Hikma issued press releases that referred to its product as “Hikma’s generic version of VASCEPA®” and “generic VASCEPA®.” Hikma referenced VASCEPA®’s total sales figures for all indications, including the CV indication. Hikma marketed its generic product on its website, and they indicated that it was therapeutically equivalent to branded VACEPA when used as labeled (AB rated).

Amarin sued Hikma for induced infringement of its patents that covered the CV indication. Amarin claimed that Hikma’s press releases, website, and product label showed Hikma’s specific intent to actively encourage physicians to prescribe Hikma’s generic product for the off-label CV indication. Hikma moved to dismiss, and the district court granted Hikma’s motion. In its decision, the district court noted that Amarin’s complaint failed to plead inducement based on either Hikma’s label or public statements. Amarin Pharma, Inc., No. 2023-1169, at 11.

On appeal, the Federal Circuit reversed, finding that Amarin’s allegations regarding the label, combined with Hikma’s public statements and marketing materials, were sufficient to plausibly state a claim for induced infringement. The court reasoned that Hikma’s label – which lacked a CV Limitation of Use – and public statements communicated to physicians and the marketplace that Hikma’s product could be prescribed for any approved use of icosapent ethyl, including the CV indication.

Hikma’s petition for rehearing en banc

In the wake of the Federal Circuit’s decision, Hikma filed a petition for rehearing en banc. In its petition, Hikma argued that the Federal Circuit panel erred in “allowing inducement claims to proceed without any statement by Hikma encouraging the claimed methods.” Amarin Pharma, Inc. v. Hikma Pharmaceuticals USA Inc., No. 2023-1169, ECF No. 47, at 11 (Fed. Cir. 2024). It further argued that the Federal Circuit’s decision rested on a theory of “passive inducement,” because Hikma’s public statements did not mention VASCEPA®’s label, or its CV indication.

As a party must “actively” encourage infringement to be liable for inducement, Hikma argued that its actions did not meet the legal requirements of induced infringement. To find otherwise would “broaden[] inducement liability beyond its statutory limits.” Id. at 21. Hikma also argued that the Federal Circuit’s decision would “vitiate” labeling carve-outs under section viii, because “the facts deemed sufficient [to please a case for inducement] here exist in every skinny-label case.” Id. at 24.

Key takeaways of the case

Amarin v. Hikma is the first time that the Federal Circuit has found plausible induced infringement by a skinny-label holder based on a holistic view of the generic’s behavior. The Federal Circuit’s panel decision, if it stands, offers lessons for both generics and patent owners.

The panel decision warned generics that “clarity and consistency in a generic manufacturer’s communications regarding a drug marketed under a skinny label may be essential in avoiding liability for induced infringement.” Amarin Pharma, Inc., No. 2023-1169, at 20. In other words, generics would need to clearly state their products approved indications, and avoid any implication that the products may be suitable for a carved-out indication.

For patent owners, the Amarin decision provides a new enforcement tool in their arsenal. Patent owners are encouraged to monitor generics’ advertising and other written communications for statements that indicate or imply the possibility of off-label use. Such evidence may now be enough to plausibly state a claim for induced infringement.

Additionally, practitioners in the pharmaceutical space are advised to follow this case as the Federal Circuit decides whether to grant Hikma’s petition for rehearing. As FDA continues to grant applications for skinny labels, these issues remain relevant to both generics and patent owners.

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