Court of Appeal holds that patent prosecution history is not a useful guide to claim construction

30 六月 2015

Back in July 2014, our litigation newsletter covered the English High Court’s decision to declare a European patent for cancer treatment not infringed in the UK, or in France, Italy or Spain. For a copy of that article, please click here.

The case has now come before the Court of Appeal, which handed down its decision on 25 June 2015 (Actavis UK Limited & others – v – Eli Lilly & Company [2015] EWCA Civ 55).

Prosecution history as a guide to construction

The proceedings at first instance were particularly noteworthy because of the judge’s consideration of the patent’s prosecution history - something which in the past the UK courts have been very reluctant to do when a construing  patent’s claims. However, this approach was firmly rejected by Lord Justice Floyd in the Court of Appeal, who described his difficulty with it as follows:

“Firstly, it assumes the skilled reader will always read the prosecution history. I do not see why this should be so, given the limited value which, at least before the judgment in this case, it was recognised to have.

Secondly, and more importantly, it suggests that the story told by the prosecution history of how the claims came to be drafted as they were will assist the court in preventing abuse of the system. To my mind this will be a very rare case indeed. Unless the acceptance of a restriction in a claim is to operate as some kind of estoppel against the patentee arguing for wider claims (a proposition for which neither the side contended…), there will always remain an issue as to whether the applicant needed to accept the restriction notwithstanding that he did so. In those circumstances, the light which the prosecution history sheds on the ultimate question of construction is likely to be extremely limited.”

Floyd LJ went on to say that as such he did not regard it as useful to go to the prosecution history in order to ascertain that the patentee had accepted a restriction to his claim against an objection of lack of support in the specification. Just because a patentee who was faced with an official objection amended his claims in light of it does not prevent him from saying he need not have done so and that the concession he appeared to make in prosecution was made incorrectly. The judge added that if it were not open to a patentee to contend that, then the prosecution history is effectively creating a form of estoppel.

As Lord Hoffman put it in Kirin-Amgen Inc. & others v Hoechst Marion Roussel Limited & others [2004] UK HL46 :

“The meaning of the patent should not change according to whether or not the person skilled in the art has access to the file, and in any case life is too short for the limited assistance which it can provide.”

It followed from the proper construction of the claim that there could be no direct infringement by Actavis.

Indirect infringement

The relevant parts of section 60(2) Patents Act 1977 state as follows:

“… a person…also infringes a patent for an invention if…he supplies or offers to supply in the United Kingdom a person other than...a person entitled to work the invention with any means relating to an essential element of the invention for putting the invention into effect when he knows, or it is obvious…. that those means are suitable for putting, and are intended to put, the intention into effect in the United Kingdom.”

The patent relates to the use of pemetrexed disodium in the manufacture of a medicament for use in combination therapy with vitamin B12 and, optionally, folic acid. This is a cancer treatment which Lilly has marketed under the brand name “Alimta”  since 2004.

The active ingredient in Actavis' proposed product is one of (a) pemetrexed diacid; (b) pemetrexed ditromethamine; or (c) pemetrexed dipotassium ("the Actavis AIs").

The judge at first instance had considered that the “essential element” had to be sodium salt (rather than potassium salt). The Court of Appeal found that the High Court had overlooked that the solution could be “pemetrexed disodium” even if the salt it was going into was not and as such had, wrongly, assumed that the pemetrexed disodium has to be in the solid form. As such, the indirect infringement claim was upheld on the basis that the compound was to be made up in saline solution.

Infringement under the laws of France, Italy and Spain

It had been common ground before the judge at first instance (as it was before the Court of Appeal) that there was no detectable difference in the laws of France, Italy and Spain on their approach to contributory infringement. It therefore followed that a declaration should also be refused for those countries.

Floyd LJ went on to say that, whilst it was therefore unnecessary for him to decide whether the courts of those countries would arrive at the same result as him on the question of indirect infringement, he would nevertheless record his conclusion that the judge was right to hold that there would be no direct infringement applying the laws of those countries either.


The Court of Appeal allowed Lilly’s appeal and set aside the declarations of non-infringement.

In submissions made after the judgment had been handed down in draft, Actavis sought alternative declarations from the court. In the result, the Court of Appeal remitted the issue of whether the supply, or offer to supply, of the Actavis AIs when recommended for reconstitution in dextrose would infringe the patent back to the High Court for directions, proper identification of the issue and trial.  

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