On 12 July 2017, the Supreme Court handed down a decision in which it has reformulated the long established test for infringement of a patent in cases where the allegedly infringing product or process is not within the ambit of the actual language used by the patentee – so-called ‘purposive infringement’. The revised test now encompasses certain variants which were unforeseeable at the priority date but would have been obvious after grant of the patent.

This new test will be welcomed by patentees as it expands the scope of protection afforded to patents in the UK. It will, however, increase uncertainty for technology users while the lower courts begin to apply the new test.

What was the dispute about?

Pemetrexed disodium is a cancer treatment which has been sold by Eli Lilly under the brand name Alima since 2004. The chemical, pemetrexed, a free acid, had long been known as an effective cancer treatment, but the side-effects of its administration were too damaging (sometimes fatal) for its use on patients. The invention in this case was that these side-effects could be circumvented by administering a salt form of the chemical, pemetrexed disodium, together with the vitamin B12.

Actavis wished to launch a generic pemetrexed product also combining vitamin B12 for cancer treatment prior to the expiry of Eli Lilly’s European pemetrexed disodium patent in June 2021. Actavis sought to avoid falling within the scope of Eli Lilly’s patent protection by not using the active ingredient pemetrexed disodium referred to in the claims. Instead, Actavis planned to use either: (a) the free acid form of pemetrexed; or (b) a different salt form (either pemetrexed ditromethamine or pemetrexed dipotassium).

In order to clear the way, Actavis applied for a declaration of non-infringement in respect of Eli Lilly’s patent. As validity was not put in issue, Actavis sought this relief not only in the UK but also with respect to the French, German, Italian and Spanish designations of the patent. In the High Court, the judge held that none of Actavis’ pemetrexed products would infringe (either directly or indirectly) in any of the jurisdictions. The Court of Appeal agreed on direct infringement but found indirect infringement in all four European jurisdictions. Both parties appealed that judgment to the Supreme Court.

What did the Supreme Court decide?

The Supreme Court:

  • allowed Eli Lilly’s appeal and found that Actavis’ products infringed the Patent in the UK as well as France, Italy and Spain; and
  • dismissed Actavis’ cross-appeal – if the products did not directly infringe, they would indirectly infringe to the extent held by the Court of Appeal.

A review of the English law of construction of patents

In reaching his decision, Lord Neuberger (with whom the rest of the Supreme Court agreed) reviewed the law of construction and in particular, the English court’s approaches in Kirin-Amgen and Improver to comply with Article 69 of the European Patent Convention (EPC) 2000 and its accompanying Protocol. This legislation provides that:

the extent of the protection conferred by a European patent…shall be determined by the claims. Nevertheless, the description and drawings shall be used to interpret the claims

and “due account” should be taken of equivalent elements to those specified in the claims. The Judge noted the Supreme Court’s comment in Schutz (UK) Ltd v Werit (UK) Ltd (Nos 1 to 3) that while it was unrealistic for different national courts of the EPC to adopt a fully consistent approach to construction “it is sensible for national courts at least to learn from each other and to seek to move towards, rather than away from, each other’s approaches“. Following its own advice, the Supreme Court accordingly considered the approach to construction in other EPC states including Germany, France, Spain, Italy and the Netherlands.

Criticism of Improver questions

Having done so, the Court found that the long-standing Improver questions as formulated by Lord Hoffman in 1990 (and based on the approach by Lord Diplock in Catnic in 1982) did not afford a “fair protection for the patent proprietor” as required by Article 1 of the Protocol. Particular criticism was levelled at the second Improver question, which the Supreme Court said placed too high a burden on the patentee – to ask whether it would have been obvious to the notional addressee that the variant would have no material effect on the way in which the invention works, given that it requires the addressee to figure out for themselves whether the variant would work. In the present case, both of the English lower Courts had proceeded on the basis that the skilled addressee did not know that the Actavis products worked. Lord Neuberger, himself a chemistry graduate, thought this was too strict a test because whilst a chemist would not know at the priority date that the different versions of the pemetrexed medicaments would work (i) salt screening was routine and (ii) the chemist would be confident they would come up with a suitable substitute for the disodium salt.

Perhaps more controversially, the Supreme Court also said that the second Improver question should apply to variants which rely on, or are based on, developments which have occurred since the priority date, even though the notional addressee is treated as considering the second question at the priority date. Here, the Supreme Court approved the approach taken by Judge Kalden, the head of the IP division in the Court of Appeal in the Netherlands who has written an extra-judicial article on this point. In it, Judge Kalden explains that infringement by equivalence in the Netherlands is not limited to variants foreseeable at the priority date as it would be unfair on the patentee if a new technique becomes available after the patent was granted which makes available an obvious variant. The UK Supreme Court agreed with this logic.

This approach also has a knock-on effect which respect to the third Improver question: whether the notional addressee would have understood from the language of the claim that the patentee intended strict compliance with the primary meaning (i.e. literal interpretation) was an essential requirement of the invention. While the Supreme Court said this third question was generally an acceptable test if properly applied, the Court noted that when considering a variant which would have been obvious at the date of infringement rather than at the priority date, it is necessary to imbue the notional addressee with more information than he/she would have had at the priority date.

Reformulated Improver questions

In light of the weight the English Courts have given to the Improver questions over the decades, the Supreme Court decided to reformulate the questions to redress their criticisms. The reformulated questions, which must now be applied in a case where the accused product does not infringe any of the claims as a matter of normal interpretation, are:

  1. Notwithstanding that it is not within the literal meaning of the relevant claim(s) of the patent, does the variant achieve substantially the same result in substantially the same way as the invention – ie the inventive concept revealed by the patent?
  2. Would it be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention?
  3. Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention?

To establish infringement, a patentee will have to establish that the answer to the first two questions is “yes” and that the answer to the third question is “no”.

Osborne Clarke comment

In the judgment, the Supreme Court describes the drafting of the Protocol on Article 69 of the EPC as “bear[ing] all the hallmarks of a compromise agreement“. It is a widely believed that this compromise was between the strict textual infringement approach, historically favoured by the English Courts, and the German courts’ pre-EPC ” doctrine of equivalence”, which considered what was in the patentee’s contemplation when drafting its patent. It would now appear the English Courts are embracing the European way. While the Supreme Court was keen to point out that the notion that a product can infringe despite an immaterial variation from the invention is not new to domestic English law, by changing the Improver test to encompass variants which were unforeseeable at the priority date, the Court has undoubtedly expanded the scope of protection afforded to patents in the UK.