Second medical use patents and skinny labels: what a generic can sell, and what the pregabalin case settled

The situation

A medicine’s compound patent and SPC have expired. The originator holds a later patent claiming the compound for the treatment of a particular condition, a “second medical use” patent, which runs for years more. Generics may sell the compound for every other use. The question is how, and what happens when a pharmacist dispenses the generic against a prescription written for the patented use.

What the patent claims

European patent law allows a known compound to be patented for a new therapeutic use. Older patents use the “Swiss-type” form (use of the compound in the manufacture of a medicament for treating X); patents filed since 2011 use the direct form the EPC now permits (compound X for use in treating Y). Either way the monopoly is the use, not the substance, and infringement turns on whether the generic’s product is for that use.

The carve-out

The pharmaceutical code lets a generic omit from its summary of product characteristics and leaflet the indications still covered by a patent in the country concerned. The result is a “skinny label”: the generic is authorised for pain and epilepsy, say, but not for the patented neuropathic pain. The licence is otherwise identical and the product in the pack is the same molecule.

The carve-out solves the regulatory problem and creates the commercial one. Prescribers write the molecule’s name; pharmacists dispense whatever generic is in stock; neither reads the label; and the originator argues that the generic knew its product would be used for the patented indication.

What the pregabalin case settled in the UK

Pfizer’s Lyrica (pregabalin) had a second-medical-use patent for neuropathic pain. Generics launched with pain carved out. Pfizer sued, and in 2015 NHS England issued guidance that pregabalin for neuropathic pain should be prescribed by brand, the first time prescribing guidance had been shaped by a patent dispute. The litigation ended in the Supreme Court in November 2018.

On validity, the patent’s claims to pain were held invalid for want of plausibility, which decided the case. On infringement, which the court addressed anyway, the majority held that a skinny-labelled generic infringes a use claim only if the product, judged by its outward presentation (its label, leaflet, packaging and the way it is marketed), is presented as suitable for the patented use. A generic that carves the indication out and does not promote the use does not infringe, whatever happens at the pharmacy counter and whatever it knows about prescribing habits. A minority would have asked about the manufacturer’s intention; the test the lower courts now apply is the majority’s.

For the UK, then, the skinny label works. The originator’s remedies lie in persuading prescribers and the health service to prescribe by brand, not in suing the generic.

Germany and the Netherlands go further

German courts have found infringement of a use patent where a generic, without presenting its product for the use, knew that its product would be dispensed for the patented indication in substantial quantities and took no steps to prevent it; the position has moved through several Düsseldorf and Munich decisions and is not settled in the generic’s favour. Dutch courts have reached similar results on similar reasoning. In those countries a skinny label is a necessary step and not a sufficient one: generics have written to pharmacists and wholesalers, excluded the use from tenders and monitored their own volumes to show they did what they could.

What it means, by role

For a generics or launch planner. A second-medical-use patent is not a reason to wait, but it is a reason to launch differently: carved-out label, no promotion for the use, and in Germany and the Netherlands a documented programme to steer the product away from the patented indication. Validity attacks on plausibility are often available, as pregabalin showed.

For a prescriber, pharmacist or health system. Brand prescribing for the patented indication is the mechanism that protects the originator’s remaining market, and the one that NHS guidance used; a reimbursement or tender rule that ignores the carve-out can drag a health service into a dispute.

For a parallel trader. Importing the originator’s own product is unaffected; importing a skinny-labelled generic into a country where the use patent is in force requires the destination’s label, not the source’s.

For a buyer. A product that is “off patent” can still be single-source for one indication for years; volumes for that indication may stay with the brand. The patent and licence records show which indications are carved out of which generics, country by country, and MPA Search carries those licences alongside the patent position.