Pemetrexed - UK

On Jul 12, 2017 the Supreme Court of UK published its judgment in Eli Lilly v Actavis case over a cancer drug Alimta (Pemetrexed). It’s five-year dispute and with both parties getting permission, the issue of direct and indirect infringement subject to the June 2015 Court of Appeal decision was up for grabs. In June 2015, Lord Justices Kitchin, Floyd and Longmore upheld Arnold’s decision in respect of direct infringement, but the three judges reversed the indirect infringement finding. The question before the Supreme Court's was whether a three products (pemetrexed diacid, pemetrexed ditromethamine, or pemetrexed dipotassium) manufactured by Actavis UK Limited and others infringes Eli Lilly and Company’s patent and its foreign designations either indirectly under s. 60(2) of the Patents Act 1977 (matter for appeal) or directly under a proper interpretation of Article 69 of the Europe Patent Convention 2000 (matter for cross-appeal).

Facts of this case are that Eli Lilly hold a patent (EP 1313508) with a Swiss form claim relating to the use of pemetrexed, in a disodium salt, in combination with vitamin B12 for inhibiting tumour growth. Actavis sought a declaration of non-infringement (DNI) in respect of its products which use pemetrexed in different salt forms, one of which was pemetrexed dipotassium.

Lilly argue direct infringement on the footing that, when properly construed Actavis’ products do fall within claim 1 of the patent, in view of the equivalence between pemetrexed disodium and the salt forms Actavis use. Lilly emphasised that the invention of its patent was the combination of the pemetrexed (which was already known to be effective at inhibiting tumour growth) with vitamin B12 (which Lilly had discovered to reduce the toxicity of pemetrexed to safe levels) and was not related to the salt-form of the pemetrexed. Lilly argued that in the field of the patent, the skilled person would readily appreciate that other salt-forms existed that would work in exactly the same way as pemetrexed disodium and so – if used in combination with vitamin B12 – would be making use of the disclosed invention. Thus, on a purposive construction, the patent is directly infringed.

Actavis argued that it was a relevant consideration that during prosecution of the patent Lilly had been required to set out a specific salt-form. Actavis submitted, extending a line of argument expressed in Virgin [2009] EWCA Civ 1062 on the knowledge of patent law that the skilled person is deemed to possess, that the skilled person was aware of the patent file and could look at the prosecution history to help them interpret the patent. They would then see that a specific salt-form was required before grant of the patent and conclude that this meant the claim should be narrowly construed to only protect the particular salt-form claimed.

The court adopted revised infringement test in this case. Court considered that infringement is best approached by addressing two issues, each of which is to be considered through the eyes of the notional addressee of the patent. These are:

1.       does the variant infringe any of the claims as a matter of normal interpretation; and, if not,

2.       does the variant nonetheless infringe because it varies from the invention in a way or ways which is or are immaterial?

If the answer to either issue is “yes”, there is an infringement; otherwise, there is not.

Applying the above issues to Actavis’ products, the Supreme Court held that they directly infringe Lilly’s patent, and pointed out that the Court of Appeal took an approach which placed too much weight on the words of the claim and not enough on the Protocol. In the view of the Supreme Court, the addressee of the Patent would understand that the reason why the claims were limited to the disodium salt was because that was the only pemetrexed salt on which the experiments described in the specification had been carried out. But it did not follow that the patentee did not intend any other pemetrexed salts to infringe. Therefore the Court concluded that, subject to considering the prosecution history, the Actavis products would infringe claim 1 of the Patent.