Skinny labelling: when foreign marketing infringes domestic patent rights

Patents are often perceived as imposing clear-cut territorial barriers: the protection granted by a patent applies only within the jurisdiction where the patent is valid. However, in today’s global pharmaceutical and technological markets, the lines can blur—particularly in the context of skinny labelling.

What is skinny labelling?

Skinny labelling is a legal marketing strategy used predominantly in the pharmaceutical sector. When a drug is protected by a patent for certain therapeutic uses but not others, a generic manufacturer may seek to enter the market by launching its product with a “skinny” version of the label. This version excludes the patented indications, thereby attempting to avoid patent infringement.

For example, if a drug is authorised for the treatment of both Disease A and Disease B, but only the treatment of Disease A is covered by a valid patent, a generic company may market its version of the drug solely for the treatment of Disease B. In theory, this avoids infringement, but the practical and legal implications are more complex.

Legal framework in Europe

Within the European Union, generic companies may apply for marketing authorisation that excludes patented indications. This possibility is expressly allowed under Directive 2001/83/EC, Article 11, which permits generic authorisations for only non-patented indications. These so-called carve-outs or skinny labels are reflected in the Summary of Product Characteristics (SmPC), which may limit the approved uses of the medicinal product to those not covered by a valid patent or Supplementary Protection Certificate (SPC).

However, the existence of a legal pathway for skinny labelling does not eliminate the risk of patent infringement. Courts evaluate not only the formal content of the label but also the commercial reality of how the product is marketed, prescribed, and used.

Indirect infringement and cross-border effects

Many European jurisdictions recognise the concept of indirect infringement. In such cases, a party may be liable not because they directly make, use, or sell a patented invention, but because they enable or encourage others to do so.

In the context of skinny labelling, a generic drug that is marketed for non-patented uses may still be prescribed for a patented indication. If the manufacturer knew or should have known that such use would occur—and especially if its marketing materials, even those distributed abroad, support that use—courts may consider this to be infringement. Increasingly, judges are willing to assess the totality of a company's conduct, including whether the skinny label is being used in good faith or as a smokescreen to enter the market for the patented use.

The importance of disclaimers

To reduce the risk of legal exposure, generic companies must go beyond merely omitting the patented use from their documentation. It is often necessary to actively disclaim the patented indication.

This may involve clearly stating in marketing materials that the product is not intended for the patented use, ensuring that sales teams are instructed not to promote the product for that use, and actively monitoring how the product is referenced by distributors, healthcare professionals, and other third parties. Courts frequently examine whether a company’s overall conduct demonstrates an intent to facilitate infringement, and vague or passive strategies are unlikely to offer effective protection.

Court cases: when skinny labels led to infringement

Several European cases have demonstrated that skinny labels can still result in findings of infringement. The case of Warner-Lambert v. Generics (UK) before the UK Supreme Court in 2018 involved the drug pregabalin, marketed by Warner-Lambert (part of the Pfizer group) under the brand name Lyrica. Pregabalin was authorised for treating peripheral and central neuropathic pain, epilepsy, and generalised anxiety disorder. However, Warner-Lambert held a second medical use patent for treating neuropathic pain.

The generic company Actavis launched its version, Lecaent, with a skinny label excluding the patented indication. Although the UK Supreme Court ultimately ruled that the patent lacked sufficient disclosure and was therefore invalid, the court noted that, had the patent been valid, the product could have infringed if it had been promoted in a way that encouraged use for the protected indication. The judgment underscored that the manufacturer’s knowledge and intent are key factors in assessing infringement.

A similar scenario played out in Germany in Novartis v. Generics. Novartis owned a second medical use patent (EP2959894) covering a 0.5 mg per day dosage of fingolimod, used in its drug Gilenya for treating relapsing-remitting multiple sclerosis. The Düsseldorf Regional Court issued a preliminary injunction to prevent generic companies from launching fingolimod products in Germany. The court ruled that off-label use by doctors could support a finding of infringement, especially where generic companies failed to take adequate steps to prevent it. However, the Higher Regional Court later overturned the injunction, allowing generic entry. The case illustrated the importance of proactive measures by generic firms to mitigate the risk of unintended use for patented indications.

In the recent Unified Patent Court case Sanofi v. Amgen, Sanofi and Regeneron alleged that Amgen’s cholesterol-lowering drug Repatha® (evolocumab) infringed their EP3536712 patent, which claims the use of PCSK9 inhibitors to reduce lipoprotein(a) [Lp(a)] in patients at risk of cardiovascular or thrombotic events. Repatha is authorised and marketed for lowering LDL-C cholesterol. Sanofi contended that the sale of Repatha, which also reduces Lp(a) as a pharmacological effect, infringed their second medical use claim. The Düsseldorf Local Division of the UPC upheld the validity of the patent but found no infringement. The court clarified that for second medical use claims, it is not sufficient that a product is capable of delivering the claimed therapeutic effect. There must be clear evidence that the product is marketed or presented in a way that leads—or is likely to lead—to the claimed use, combined with knowledge or reasonable foreseeability on the part of the alleged infringer.

A skinny approach: not for pharma only

Although the concept of skinny labelling originated in pharmaceuticals, the underlying legal challenge—marketing a product for a patented use while attempting to avoid liability—can arise in other technical fields.

Consider the following fictional example. A Dutch company manufactures ultrasonic cleaning machines, which can be used for various purposes, such as cleaning surgical tools, industrial parts, or semiconductor wafers. A competitor holds a German patent for the specific use of ultrasonic cleaning in semiconductor manufacturing. To avoid infringing that patent, the Dutch manufacturer removes all references to semiconductor applications from its German documentation.

However, from its offices in the Netherlands, the company emails brochures and promotional materials to German customers, suggesting that the machines are highly effective for delicate electronics and microchip surfaces. Although the label is formally limited to general cleaning uses, the competitor may argue in a German court that the Dutch company indirectly infringes the patent by encouraging German customers to apply the machine in the patented way.

Moreover, if the same patent (or a national equivalent) exists in the Netherlands, the communications originating from the Netherlands could constitute infringement under Dutch law as well. Even if no Dutch patent exists, the German court may still take into account the cross-border marketing in assessing intent and inducement.

Final thoughts

Europe permits skinny labelling, but the margin for error is narrow. Courts increasingly adopt a pragmatic approach, evaluating the overall commercial behaviour of companies, not just their paperwork. A manufacturer may appear compliant on paper yet still infringe in practice if it facilitates, enables, or encourages the use of a product for a patented purpose—whether directly or through cross-border marketing.

For companies operating in the pharmaceutical and technical sectors, this calls for careful regulatory planning, coordinated legal strategies across jurisdictions, and well-documented disclaimers and compliance protocols. A proactive approach is essential to avoid the reputational and financial risks associated with patent litigation.