Source: Arnold & Porter Kaye Scholer LLP, via Mondaq, 19 July 2017
“The UK Supreme Court has overturned existing case law to, for the first time, formally recognise a “doctrine of equivalents”, resulting in a broader scope of patent protection under UK law. This new approach is more patentee-friendly and brings the UK into closer alignment with courts elsewhere in Europe and in the US.
Historically the English courts have held that the wording of the claim is decisive when determining whether a patent is infringed, resulting in a relatively narrow scope of protection. The Supreme Court held that this approach placed too much weight on the words of the claim and did not provide fair protection for patent holders. Fair protection requires a broader scope of protection, extending beyond the wording of the patent claims to also cover products which are technically equivalent. In the case at hand, the Supreme Court held that Eli Lilly’s patent claims covering “pemetrexed disodium” would be infringed by Actavis’ products containing various alternative forms of pemetrexed, which did not fall within the wording of the claims, properly interpreted, but were nonetheless technically equivalent.”
“The Supreme Court’s decision represents a significant departure from the established English case law in this area. It marks both a more patentee-friendly approach, and an increased desire to ensure harmonisation with the approach taken elsewhere in Europe.
The Supreme Court’s decision to depart from the literal meaning of the words used in a patent claim could be viewed as a contrast to the approach it has taken in recent cases relating to contractual interpretation, where the Supreme Court has (in Wood v Capita and Arnold v Britton  AC 1619) rejected attempts to depart far from the plain wording of a contract.
In the view of the Supreme Court this results from the distinction between (1) the meaning of the words in a patent claim, which is to be determined following the principles of construction common to all legal documents, and (2) the scope of protection of the patent, which is subject to an express requirement to ensure fair protection for the patentee which is unique to the law of patents.”