On 14 September 2018 the UK Supreme Court unanimously opined that the marketing of generic pregabalin by Actavis would not have been an infringement of Warner-Lambert's claims directed to a further medical use of pregabalin, namely for the treatment of pain. The judgment, summarised in an earlier post, dealt for the first time with the issue of how infringement of ‘second medical use’ patents should be assessed in the UK. This article explores the implications of this aspect of the judgment and its potential impact on the value of second medical use patents.

Key points on second medical use claims in Europe

Second medical use patents are available in Europe to reward the development of a new medical application for a known drug. Methods of treatment are excluded from patentability in Europe, but inventions in this field could traditionally be protected via the so-called 'Swiss-type' claim format(1): "Use of compound X in the manufacture of a medicament for medical condition Y". In December 2007, the so-called 'EPC2000' format was introduced: "Compound X for use in the treatment of condition Y". The Swiss-type format was abolished in Europe for any applications filed after 29 January 2011, but this format remains relevant for earlier patents.

It was the intention of the legislator that the EPC2000 claim format would afford protection equivalent to that of the Swiss-type format. However, the EPO's Board of Appeal held in T1780/12 that a Swiss-type claim is a purpose-limited process claim, whereas an EPC 2000 second medical use claim is a purpose-limited product claim. The Board concluded that there is variance in the protection afforded by these two different claim formats. According to the Board, a purpose-limited process claim (i.e. a Swiss-type claim) confers less protection than a purpose-limited product claim (i.e. an EPC 2000 second medical use claim).

This distinction has been adopted by several national courts, notably the UK courts, whereas e.g. German and Dutch courts treat both claim types as affording equivalent protection (2),(3).

Basic facts of the UK Warner-Lambert case 

Warner-Lambert established that pregabalin, a drug already on the market for the treatment of epilepsy and generalized anxiety, was also effective in the treatment of pain.  The Company obtained a second medical use patent in this regard.

Once any European patents protecting pregabalin itself and the use thereof in the treatment of epilepsy and generalized anxiety had expired, generics manufacturer Actavis launched the drug in Europe. To avoid infringement of the pain patent, the generic drug was launched under a 'skinny label' for the off-patent indications epilepsy and generalised anxiety disorder.

However, concerned that the generic drug would nevertheless be used for the treatment of pain, Warner-Lambert brought an infringement action against Actavis. This was the first time that the UK courts were asked to consider how infringement of second medical use patents should be assessed.

Potential infringement tests

The UK courts had to grapple with the issue of how to devise an infringement test that provides the patentee with a fair monopoly for his patented invention, without depriving generics companies of the opportunity to enter the market in the off-patent field.

At first instance, a ‘subjective intent’ test was proposed, under which there is infringement if the manufacturer makes the product with the intent to target the patent-protected market.

By contrast, an ‘objective intent’ test was favoured at the appeal stage. Under this test, a manufacturer must be taken to intend the foreseeable consequences of his actions. However, the intention will be negatived where the manufacturer has taken all reasonable steps within his power to prevent the consequences occurring.

Both of these tests were rejected by the majority of the UK Supreme Court judges. As Lords Sumption and Reed put it: "a test for infringement which depended on intention, whether objective or subjective, would be contrary to principle and productive of arbitrary and absurd results" [paragraph 71].

Instead, Lords Sumption and Reed concluded that infringement depends on the physical characteristics of the product as it emerges from the relevant process, including its formulation and dosage, packaging and labelling and the patient information leaflet, which in the EU will identify the conditions for whose treatment the product is intended. This is referred to as the ‘outward presentation’ test [paragraph 84].

However, the outward presentation test was rejected by Lords Briggs and Hodge, who favoured a subjective intention test [paragraphs172-174; 188].

A somewhat intermediate position was taken by Lord Mance.  He acknowledged that in some cases, it may not be appropriate to consider the outward presentation in isolation, without regard to issues such as advertisements by the manufacturer, or the manufacture of the drug in quantities that greatly exceed the market for the off-patent indication [paragraph 217].

Value of second medical use patents in the UK

The judgment acknowledged that - in view of the UK's regime for prescribing and dispensing drugs - package labels limited to an off-patent indication will not necessarily prevent the generic drug from being dispensed for the patented indication in the UK [paragraph 128]. The proposal of the ‘outward presentation’ test by Lords Sumption and Reed has therefore prompted innovators to question the value of second medical use patents.

However, it must be remembered that Supreme Court held that the claims at issue before it were invalid, so the comments on infringement were obiter and hence do not represent a binding authority.

Uncertainty therefore remains over what the correct infringement test should be, so it would be premature to conclude that an 'outward presentation' test will indeed be applied in all future cases. Moreover, it is entirely conceivable that the 'outward presentation' test will evolve, as it has done in Germany (see below).

It is also important to note that in the Warner-Lambert case the same formulation and dosage regime was suitable for the patented and the off-patent indication, whereas in many cases differences in the formulation and/or dosage may well make it less appropriate to dispense a generic drug for a patented indication.

It should also be remembered that generic drug marketing under a skinny label is only possible where the active ingredient is authorised for the treatment of an off-patent indication. There are many instances where a first medical treatment with a particular active agent has been investigated to some extent, and some results have published, but no relevant marketing authorisation exists. In such instances, an invention relating to a different medical treatment with the active agent may only be patent protected via a second medical use claim, but the patent would cover the only authorised indication. The absence of a marketing authorisation for the first medical treatment would prevent a generic company from launching a skinny label generic of the active agent.

It must also be appreciated that the Warner-Lambert case concerned the Swiss-type medical use claim format, which is only relevant to historic patents, whereas more recent and future patents contain second medical use claims in the EPC2000 format. As mentioned above, in the UK EPC2000 claims are considered to be purpose-limited product claims. The infringement of such claims has not yet been tested before the UK courts, but it is surely only a matter of time before the UK courts will be asked to consider this issue.

Another important factor to bear in mind is that the approach proposed by the UK Supreme Court differs from the practice that has developed in other European countries, such as Germany and the Netherlands (discussed below).

Second medical use patents in other European jurisdictions

There is a significant lack of harmonisation among the various European countries regarding the interpretation of second medical use claims and the assessment of infringement of such claims.

In particular, whilst the UK courts have adopted the position that Swiss-type claims do not confer the same protection as EPC 2000 claims (see above), the Supreme Courts of Germany and the Netherlands do not distinguish between these different claim formats when assessing infringement.

Traditionally, German courts assessed infringement of such claims by considering the 'sinnfällige Herrichtung' (which roughly translates as 'manifest arrangement')(4), which has been equated to the 'outward presentation' test. However, the jurisprudence is constantly evolving and more recent decisions(5) highlight that when assessing infringement, the German courts are increasingly prepared to take into account factors going beyond the drug label and package insert.

In the Netherlands, the Supreme Court has adopted an objective foreseeability test(3) and established that if use of the generic drug for the patented indication is foreseeable, the generic manufacturer/supplier should implement effective measures to try to prevent the generic product from being dispensed for the patented indication.

Outlook

It is debatable whether the approach for assessing infringement of Swiss-type second medical use claims in the UK proposed by the UK Supreme Court strikes the right balance between allowing the manufacture and supply of generic drugs for off-patent indications and providing adequate protection for the holders of patents with Swiss-type second medical use claims.  However, the law is far from settled in this area, and it is conceivable that UK practice may in future become more aligned with German or Dutch practice in this field, which is widely considered to be more favourable to patentees. The importance of second medical use patents in Europe should therefore not be underestimated.

Footnotes

(1) G5/83 confirmed that the Swiss-style claim format may be used to protect a second/further medical use

(2) For example, in "Kollagenase I" the German Federal Supreme Court did not distinguish between the different kinds of claim language.

(3) Merck Sharp & Dohme Corp. v. Teva Pharma B.V. and Pharmachemie B.V., Supreme Court of The Netherlands, The Hague, 3 November 2017, Case no ECLI:NL:HR:2017:2807

(4) For example "Ribavirin“ Düsseldorf District Court, docket number 4a 0 12/03

(5) "Dexmedetomidin" Düsseldorf Higher Regional Court decision of March 2018 Az. I-2 U 30/17