Warner-Lambert v Actavis: Supreme Court Considers Medical Use Claims

The Supreme Court in the UK handed down its decision in Warner-Lambert v Actavis on 14th November 2018 (and a copy of the complete decision is available here). The Supreme Court considered the following issues in its judgment:

how much data is required in the application as originally filed to support a second medical use claim; and the circumstances under which "cross label use" for the patented indication of a drug sold by a competitor company can constitute infringement of a second medical use claim. "Second medical use" claims in Europe

The de novo discovery of effective and safe pharmaceuticals is a challenging process, and many new drugs do not ultimately show sufficient efficacy against their target disease to secure regulatory approval. For this reason, there is an extensive and growing list of drugs which have shown an acceptable safety profile in human trials, but which have failed late stage clinical trials, and which are therefore no longer under development.

Increasingly, unmet medical needs are being met by "repurposing" of such old medicines for new diseases. Generally, much less investment is needed for clinical investigation of the activity of such an old medicine against a new disease than would be required to develop a wholly new drug to treat the disease at issue. Nevertheless, considerable resources are still required to carry out the necessary clinical trials to assess whether or not known drugs have activity against new target diseases.

For this reason, a finding that a known drug has efficacy against a new disease target has long been thought to be a finding which merits patent protection. To that end, since the 1980s, the European Patent Office (EPO) has been willing in principle to grant claims in "second medical use" format. The original claim format for a second medical use claim was the "Swiss-style" claim format, approved in Decision G5/83, published in the Official Journal of the EPO in March 1985. Then, following the changes to the EPC which took effect in 2007, second medical use claims were granted in "product for use" format1.

The two claim formats are set out below.

"Swiss-style" claim: Use of [known drug] in the manufacture of a medicament for use in [treating new disease target] "Compound for use" claim: [Known drug] for use in [treating new disease target] The question then arises as to how such claims can be infringed. Commercial sale of most medicinal products in the EU is governed by Directive 2001/83/EC. Under this Directive, no medicinal product may be placed on the market of a member state unless a marketing authorisation has been issued. A summary of the product characteristics (SmPC), which includes therapeutic indications and dosages, must be submitted as part of the application for a marketing authorisation. Subsequently, when the medicinal product is marketed it must be accompanied by a package leaflet. That package leaflet must specify, inter alia, the therapeutic indications and dosages set out in the SmPC.

Article 10 of Directive 2001/83/EC permits generic pharmaceutical companies to secure marketing authorisation for a drug simply by demonstrating that the drug is a generic version of a reference medicinal product which has been approved following a full set of clinical trials. Under such circumstances, the SmPC for the generic product will be identical to the SmPC which accompanied the initial marketing authorisation for the reference product, but with one important exception. Article 11, final paragraph, of the Directive specifies that:

"those parts of the summary of product characteristics of the reference medicinal product referring to indications or dosage forms which were still covered by patent law at the time when a generic medicine was marketed need not be included".

Thus, generic manufacturers may adopt a so-called "skinny SmPC", which omits patented indications and dosages. It has been a matter of debate whether or not sale of a drug covered by a second medical use claim under such a "skinny SmPC" can infringe the second medical use claim under circumstances where the generic product ends up being used, to greater or lesser extent, to treat the patented indication in patients.

Warner-Lambert v Actavis: The dispute

The dispute between Warner-Lambert and Actavis concerned the drug pregabalin. This drug was marketed by Warner-Lambert under the tradename Lyrica® for three indications (epilepsy, generalised anxiety disorder and neuropathic pain). Patent protection for pregabalin per se expired in October 2013, and an SPC covering the product had been allowed to lapse. However, Warner-Lambert held a second medical use patent containing "Swiss-style" claims covering one of the three indications (neuropathic pain). The relevant claims are set out below:

Claim 1: Use of [pregabalin] or a pharmaceutically acceptable salt thereof for the preparation of a pharmaceutical composition for treating pain. Claim 3: Use according to claim 1 wherein the pain is neuropathic pain. Dispute on validity

The dispute on validity was focussed on claim 3. It was common ground that pregabalin did in fact have efficacy in treating neuropathic pain. However, the parties differed on whether or not that activity was made plausible from the results in the patent specification as originally filed.

The patent specification...