Drug reformulates test for patent infringement

Working out what infringes a patent has always been a tricky question. In recent years the UK has followed an approach derived from cases such as metal lintels for buildings and epilators, devices for removing body hair. The UK court decided, for example, that a hair removal product relying on a slotted rubber rod did not infringe a patent which described the invention as requiring a coiled metal spring. Good sense, some might think – but not the same conclusion reached in three EU countries in respect of the same product.

Recently, the UK Supreme Court has revisited that question – now relying on an amendment to the legal texts defining the scope of protection given by a patent (Actavis UK Limited v Eli Lilly and Company). In this decision the UK seems to have taken a new direction, one more explicitly closely aligned with that elsewhere in Europe. This is good for those looking for a harmonised approach. But, although it recites one of the legal objectives, that the approach should provide a degree of each certainty, what is certain is that the decision raises as many questions as it answers:

  • the scope of claims will likely be broadened – but just how broad? and
  • will the scope be the same for both validity and infringement?

The new formula

The case under review by the Supreme Court involved pharmaceutical formulations including the chemotherapy drug pemetrexed (we'll call it “P” for short), along with vitamin B12 to mitigate potentially fatal side effects of the drug. The generic drug company Actavis planned to sell such formulations.

Eli Lilly sells a very successful medicine of this kind under the name ALIMTA using P in the form of a sodium salt. This is also the form of the drug specified in Lilly’s patent claims. Importantly, Actavis planned to make a product with P in a different form: either the diacid (with two acid groups and no sodium ions), the ditromethamine, or the dipotassium form (with two potassium ions instead of sodium ions).

The dispute began with an application by Actavis for declarations of non-infringement in respect of the supply of the diacid version in the UK, and unusually in UK proceedings, also the equivalent patents in Italy, France and Spain. The inclusion of these other European countries may explain the Supreme Court’s focus on reviewing the position to create a more harmonised answer.

Journey to the Supreme Court

At first instance, the trial judge concluded that none of Actavis’s proposed products would infringe. His analysis followed the well-trodden path of the "the Improver questions" (named after the disputed hair removal device), since renamed "the Protocol questions", and the later analysis given in Kirin-Amgen v Hoechst Marion Roussel and Virgin Atlantic Airways Ltd v Premium Aircraft Interiors. He came down on the side of non-infringement.

Lilly appealed. The Court of Appeal took Lilly's side, at least on indirect infringement (that is that the diacid or potassium salt was supplied knowing, or intending that when it was used by the patient, it would be converted to the equivalent disodium form). On direct infringement (did the product itself actually fall within the scope of the patent?), the decision for Actavis stood. Both sides appealed to the Supreme Court, Lilly on direct infringement and Actavis on indirect infringement.

Closer to our European neighbours

Ultimately, the courts have to apply Article 69 of the European Patent Convention 2000 (“EPC 2000”), along with its explanatory Protocol. (EPC 2000 slightly amended the former wording in the European Patent Convention.)

What the Courts are directed to look for is “a position between [the] extremes” of “the strict, literal meaning of the wording used in the claims” and “the claims serv[ing] only as a guideline”.

The Supreme Court considered how this is done in other European countries, and reached the following conclusions.

  • You cannot treat this as an exercise in understanding the words on the page. (The previous UK approach had been to apply the Protocol by looking at what the words mean and extending that meaning beyond the literal meaning). The Supreme Court pointed out that infringement in accordance with the Protocol is separate from infringement by analysing the words of the claim. Mixing these two things up leads to confusion, both in patent cases and in the wider law on the interpretation of contracts.
  • The Improver questions need improving. In the style of magazine make-overs, we’ll compare them side by side:

Question 1


Does the variant have a material effect upon the way the invention works? If yes, the variant is outside the claim.


Notwithstanding that it is not within the literal meaning of the relevant claim(s) of the patent, does the variant achieve substantially the same result in substantially the same way as the invention, ie the inventive concept revealed by the patent?

Question 2


Would this (ie that the variant had no material effect) have been obvious at the date of publication of the patent to a reader skilled in the art? If no, the variant is outside the claim.


Would it be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention?

Question 3


Would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention? If yes, the variant is outside the claim.


Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention?

There is a subtle difference in Question 3 – this no longer refers to the language of the claim – but this is something which has probably rarely followed in practice anyway.

The really big difference here is in Question 2.  It involves some time travel to be undertaken by the skilled reader. She reads the patent at the priority date, but she benefits from later acquired knowledge about whether and maybe how the variant works. In particular the test is to be applied on the basis that it is known the variant actually works, whether or not that would have been obvious at the priority date.

What does this mean for business?

  • The new approach seems to make it quite a bit more difficult to design a workaround to a patented invention. Relying on the Question 3 “the patentee nonetheless intended strict compliance with the literal meaning” will often be uncertain. Essentially, in relation to Question 2, you may have to look at the patent and see what the underlying principle is and then take steps not to adopt that. This also involves understanding what the underlying principle actually is. To reduce risk you would have to look as broadly as possible unless there is something in the patent which makes clear it is narrower. 
  • But of course any extension of the scope of a patent should make it easier to invalidate it on the basis of prior art. The Supreme Court did not have to address this. One concern is the possibility that the claim scope could be held to be broader for the purposes of infringement than it is for analysing validity. Because the second question has been changed to include information becoming available after the priority date, something which falls within the claims under the three questions might not be enough to make the claim obvious at an earlier time, namely at the priority date.
  • Moreover the scope could “change” as the patent matures – or strictly speaking the appreciation of the scope may change – or of more concern to the patent draughtsman, now, when assessing novelty, obviousness and sufficiency, even non-obvious variants/equivalents should be taken into account. A task requiring a crystal ball.

Overall, the decision will be welcome news to patentees, but concerning to those who might be threatened with infringement proceedings. And a chilling effect on generic producers seems likely given the wider aura of potential infringement around patent claims.

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Every piece of content we create is correct on the date it’s published but please don’t rely on it as legal advice. If you’d like to speak to us about your own legal requirements, please contact one of our expert lawyers.

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