Most European national patent laws provide for an "experimental use exemption" to patent infringement, in many cases based on the Community Patent Convention (CPC).

In the UK, the exemption can be found in section 60(5) of the Patent Act 1977 which provides that:

"An act, which, apart from this subsection, would constitute an infringement of a patent for an invention, shall not do so if…

(b) it is done for experimental purposes relating to the subject-matter of the invention


In general terms, the effect of this provision is that it will not be an infringement of a patent to use a patented product or process for experimental purposes relating to the subject matter of the invention. This defence to patent infringement is of particular interest to the pharmaceutical and agrochemical fields, where some sort of testing activity must be undertaken before a new drug or pesticide can be placed on the market.

In the pharmaceutical field in particular, the experimental use exemption is important for both the research based pharmaceutical industry and the generic industry, despite their differing perspectives. Research based pharmaceutical companies generally want as little erosion as possible of their patent monopoly. However even these firms may wish to investigate a competitor’s patented compounds with a view to making new inventions based on the patented subject matter. Generic pharmaceutical companies may wish to experiment on patented compounds and the use results of their experiments to submit test data to the marketing approval authorities. This may enable them to put their products on the market on the very first day after the dominating patents have expired.

Background to the approach by the English Courts

What does "experimental purposes" mean?

The leading UK authority on section 60(5)(b) is Monsanto Co v Stauffer Chemical Co1. In this case, the Court of Appeal considered the meaning of the word "experiment" and concluded that activities carried out in order to discover something unknown or to test a hypothesis can fairly be regarded as experiments, even if they have a commercial end view.

The Court of Appeal concluded that trials carried out in order to discover something unknown or to test a hypothesis would fall within the exemption, but trials carried out to demonstrate to a third party that a product works, or to amass information to satisfy a third party that a product works, would not fall within the exemption.

What does " relating to subject matter of the invention"mean?

In addition to establishing that a Company’s activities are experimental (using the test established in Monsanto), to benefit from the exemption it is essential that the experiments relate to the subject matter of the invention disclosed in the patent. The UK court considered this aspect of s60(5)(b) in Smith Kline & French Laboratories Limited v Evans Medical Limited2.

In this case the court confirmed that s60(5)(b) may cover experiments carried out with a commercial end in view, but also found that the purpose of the experiments had to relate to the subject matter of the invention of the patent in suit in the sense of having a real and direct connection with the subject matter. In this case, the experiments on material covered by the patent were not being carried out to investigate the invention of that patent but for the purposes of litigation in order to invalidate the patent and were held not to be covered by s60(5)(b).

A new approach?

The emphasis by the English Courts on the primary or predominant motive behind the trials led to the conventional English view that clinical trials for the purpose of obtaining market approval were unlikely to fall within the experimental use exemption. However, more recent decisions of the German and French Courts have shown a more liberal approach to the interpretation of the exemption in particular the Clinical Trials I and II cases of the German Federal Supreme Court. Both cases involved patented proteins that were being used by the defendants. In Clinical Trials I this was with a view to obtaining a compulsory licence, and in Clinical Trials II this was with a view to obtaining market authorisations. In both cases it was held that the clinical trials fell within the exemption.

The approach of the German courts in Clinical Trials I and II has thrown doubt on the "traditional" English view of whether clinical trials constitute patent infringement. These cases are likely to be influential on any English court considering the issue in the future. Accordingly, the English Courts are now more likely to be receptive to the argument that clinical trials conducted within the UK are within the research exemption provided that they could be said to be finding out new information about the invention. However, until such a case is brought before the English Courts, it is unclear where the English Courts will draw the line, particularly regarding Phase III trials.

Future European legislation

By 30 October 2005 at the latest, the amendments to Directive 2001/833, which establishes the framework for the grant of marketing approval for medicinal products in Europe, adopted in Directive 2004/274 must be implemented into the national laws of the Member States of the EU. One amendment (the so called ‘Bolar-provision’) introduces a new Article 10(6), which provides for an exemption to patent infringement for the conduct of "necessary studies" and the "consequential practical arrangements" for the purpose of submitting an application for a marketing authorisation for a medicinal product under the abridged/generic medicinal product procedure or the new simplified procedure for biosimilars. Such studies may be needed, for example, for the purpose of establishing bioequivalence to the reference medicinal product.

Implementation of the new Article 10(6) in the UK requires an amendment to the UK Patents Act 1977 most likely to section 60(5). In March 2005 the UK Patent Office distributed a proposal to interested parties as part of a consultation process for the introduction of a new exemption. Like the new Article 10(6), the scope of the proposed UK exemption would be limited to activities carried out to support an abridged application or the new simplified procedure for biosimilars. The new legislation therefore provides only a limited exemption for carrying out clinical trials. Although the consultation period has closed, draft-implementing legislation for the new Article 10(6) has not yet been published.

If, as seems likely, the new provision is implemented in the UK to reflect the exact wording of Article 10(6), the UK courts may find it difficult to extend the interpretation of the experimental use exemption to cover all clinical trials. However, the implementation of Article 10(6) in other Member States may reflect the more liberal interpretation of the experimental use exemption currently applied by the courts in those Member States. Ultimately only a reference to the European Court of Justice will determine the scope of the new exemption.


1. 1985 R.P.C. 515

2. As further considered by the Court of Appeal in Auchinloss v Agricultural & Veterinary Supplies Ltd 1999 RPC 397

3. OJ L-311, 28/11/2004, p.67-128

4. OJ L-136, 30/04/2004,p. 34-57

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.