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Actavis Group PTC EHF & Others v (1) ICOS Corporation (2) Eli Lilly & Company

The UK Court of Appeal has recently handed down its decision in Actavis v ICOS. Lewison, Kitchen and Floyd LLJ held that ICOS’s patent EP (UK) 1,173,181 (the “Patent”) was invalid for obviousness overturning the first instance decision of Birss J. The decision is an analysis of the “obvious to try” approach which arguably makes the revocation of patents easier, particularly in the pharmaceutical and biopharmaceutical fields, in which research tends to follow a rational path. Its importance as a decision is evident from the fact that all three Lord Justices provided their views on the issue of obviousness.

The Patent claimed, inter alia, the use of tadalafil (sold under the trade name Cialis by Eli Lilly) in a low 5mg daily dose in the treatment of sexual dysfunction. Cialis is a competitor (second in class) of the well-known drug Viagra for erectile disfunction (“ED”).

While there were a number of issues the main argument concerned obviousness. However, first an issue of claim construction arose. Interestingly, therefore, Kitchin LJ commented on the state of the law following the Supreme Court judgment in Actavis v Eli Lilly & Co ([2017] UKSC 48). The point that arose was whether that decision had changed the law of normal interpretation in the circumstances of the case, the parties agreed it had not. The correct approach to claim construction remained determining “what the person skilled in the art would have understood the patentee to be using the language of the claims to mean” (see [44]).

(Note that in the recent first instance decision of Generics (UK) v Yeda ([2017] EWHC 2629 (Pat)) Arnold J also held that the law of normal interpretation had not changed, where the point was argued. See [134] to [138].)

Once interpretation of the claims was resolved the issue of infringement fell away. The proposed sales by the claimants would infringe. The claimants’ arguments on priority, added matter and novelty also failed. Interestingly, the novelty citation “Stoner” (an application by Merck Inc, not a party to the proceedings) had to maintain its priority entitlement (it was only Art 54(3) EPC prior art).

Legal priority of the Stoner citation was attacked by ICOS on the basis that there was no evidence that title to the priority right had been properly assigned. Neither party adduced evidence at first instance. The burden was initially on the claimants but it was held that enough had been done to transfer the burden to the patentee. Kitchin LJ agreed with the judge (see [97]).

Turning to the obviousness issue, the dispute was concerned with a citation referred to as Daugan. This reference taught the use of a class of compounds, including tadalafil, for treatment of ED. The IC50 of tadalafil is given and a 50mg dose is described. There was no dispute that based on Daugan, tadalafil was of interest and would be investigated by the skilled team. The dispute was whether the investigations that would be carried out in such circumstances could give rise to a valid (non-obvious) patent.

In pharmaceutical development a drug candidate must progress through pre-clinical (in vitro and animal) testing and into clinical trials. Such trials also progress stepwise, firstly Phase I safety testing, then Phase IIa efficacy (generally single dose) and Phase IIb (dose ranging) and then Phase III. Given that Daugan disclosed a 50mg dose the main issue was whether it was obvious to undertake clinical development through to Phase IIb with a dosage regime as low as 5mg.

The reasoning is very fact based but ultimately it appears from Kitchin LJ’s judgment that so long as the skilled team continues to be motivated along the clinical development pathway and that they are approaching the various stages with an expectation of successfully obtaining the type of information that the particular stage of research is intended to provide (e.g. with Phase IIb an understanding of the dose response relationship) then there can be no invention. This stands even if there are surprising discoveries along the way (in this case that the dose that was effective was as low as 5 mg).

There exists now, in English law, perhaps a greater emphasis on the types of testing that the skilled team do as a matter of routine irrespective of any expectation of success, see Floyd LJ at [160] in general and his conclusion at the end of [171].

The decision appears to be discouraging for patents in sectors where research follows an established rational path. Although a novel and inventive dosing regimen is in principle patentable in the UK, it may be difficult to convince the UK courts of this if the relevant drug is known to be a potential therapeutic candidate and it can be shown that the dosing regimen would be arrived at by way of routine work.

A copy of the judgment can be found here.

Headnote: Ian Turner, Marks & Clerk Solicitors LLP