The UK is one of the key jurisdictions for patent disputes in Europe and its specialist patents judges are highly experienced. So it may be hard to believe that key concepts of patent infringement in the UK, under our Patents Act 1977, are still being worked out. But in Actavis –v- Eli Lilly, Lord Neuberger, giving one of his last judgments before retirement from the Supreme Court, has overturned established principles, making the English Patents Court more attractive for claimants.
The case related to medicines but the principles are applicable to any technical field. The claims of the patent specified that a particular antifolate salt (pemetrexed disodium) should be administered with vitamin B12. Actavis sought a declaration that its medicines containing different pemetrexed salts (such as pemetrexed dipotassium), or pemetrexed free acid, did not infringe, because they did not comprise the specified disodium form. The court determined the question of infringement not only for the UK but also for France, Italy and Spain.
The Supreme Court reversed the lower courts, finding that the Actavis products directly infringed the patent despite not comprising the compound specified in the claims. The essence of the invention was the combination of pemetrexed diacid, or any pemetrexed salt, with vitamin B12. Admittedly the Actavis products did not infringe under the first branch of the infringement test, namely whether they fell within the claims as a matter of ‘normal interpretation’ of the language used in the document. (‘Normal interpretation’ could include, for example, interpreting ‘vertical’ as encompassing angles a few degrees off strict vertical.) The Actavis compounds were a variant from the language used in the claims. But the Court then created a new, second branch of the infringement test, focused on whether a variant infringes because it varies only in immaterial ways.
The correct approach to variants is not merely to interpret the words of the claim in context, as had been understood previously. The approach previously taken, in accordance with Lord Hoffmann’s 2005 judgment in Kirin-Amgen, should no longer be followed. This excluded from infringement variants that the European Patent Convention intended should infringe as ‘equivalents’. For example, in the leading earlier case of Improver –v- Remington, a claim to a device comprising a ‘helical metal spring’ could never be satisfied by a slotted rubber rod as a matter of language alone, even if the difference were technically immaterial. As such, if Improver were decided today, the outcome may be different.
In conclusion, Lord Neuberger introduced a new three-step test which, crucially, imbues the notional reader of the patent with the knowledge that the variant achieves substantially the same result as the invention specified in the claim. This opens the way for pursuit of bolder claims of infringement where the accused product or process is not within the meaning of the claim language used.