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Regen V Estar: Applying Actavis To Numerical Limitations

The Supreme Court introduced a doctrine of equivalents into the UK patent infringement system for the first time in Actavis v Eli Lilly ([2017] UKSC 48). Regen v Estar ([2019] EWHC 63) applied this new approach to a claimed numerical limitation.

The patent related to a method for producing a platelet-rich plasma by centrifuging blood. Claim 1 included a step of centrifuging whole blood in a glass separator tube containing a polyester-based thixotropic gel and a buffered sodium citrate solution at 0.10M. The patent was found invalid for lack of novelty and inventive step, but the question of infringement is of interest because of the way it applied the Actavis questions to the numerical limitation in claim 1.

According to Actavis, whether an item directly infringes a patent is best approached by addressing two questions: 1. Does the item infringe any of the claims as a matter of normal interpretation; and if not, 2. Although the item may be characterised as a variant, does it nonetheless infringe because it varies from the invention in a way which is immaterial?

Guiding principles for construing numerical claims can be found in the case law. Smith & Nephew v Convatec Technologies ([2015] RPC 32), for example, sets out various points of relevance – such as the number of decimal places or significant figures to which the numerals in the claim have been expressed – for assigning a range that a numerical limitation can be fairly considered to cover. Regen v Estar does not overturn these principles but places them firmly within the scope of the first Actavis question, i.e. the assessment of normal construction. The doctrine of equivalents in the second Actavis question is something additional.

The defence argued that the doctrine of equivalence should not apply to claim 1 because of its numerical limitation. This argument was dismissed by HHJ Hacon. The reasons were two-fold. First, it would put numerical claims in a special class: the doctrine of equivalents does not apply to them. Second, normal construction of a claim may be narrower than the purposive construction under Kirin Amgen, so if the defendants were correct the effect of Actavis would be to narrow the scope of numerical claims, which HHJ Hacon believed would be contrary to the intention underlying the Supreme Court’s judgement in Actavis.

Regen v Estar then turned to the doctrine of equivalents under the second Actavis question. A distinction was drawn between the invention as a whole (which is what is claimed) and the inventive concept (which is the new technical insight conveyed by the invention, or “the clever bit”). HHJ Hacon encapsulated what he believed was the inventive concept underlying the patent in a paragraph of the judgement that remarkably resembles a claim (one that is considerably broader than claim 1). HHJ Hacon then found that had the patent been valid, it would have been infringed.

It has traditionally been the view – in the UK and elsewhere – that where a claim specifies a numerical value this should be a clear enough indication that the patentee did not intend the scope of the claim to extend outside that limit. Regen v Estar teaches that the approach to determining the scope of numerical claims should be no different from that applicable to any other claim. In the new spirit of generosity that UK courts are showing patentees, that apparently means that numerical limitations can be disregarded entirely in favour of an “inventive concept” that is rooted in the specification rather than the claims. Indeed, in Regen v Estar, the claims appeared to be largely superfluous to the question of infringement.