ACTAVIS GROUP PTC EFH v ICOS CORPORATION

[2018] R.P.C. 7 363 ACTAVIS GROUP PTC EFH v ICOS CORPORATION1 COURT OF APPEAL Lewison, Kitchin and Floyd L.JJ.: 12, 13 July and 1 November 2017 Patents – European Patents – Pharmaceuticals – Tadalafil – Dosing regimens – Revocation – Infringement – Construction – Priority – Added matter – Novelty – Copending applications – Entitlement to priority – Burden of proof – Obviousness – Obvious to try – Fair expectation of success – Dose ranging studies – Appeal to Court of Appeal H1 H2 H3 Patents Act 1977, ss.2(3), 72 European Patent Convention, arts.54(3) This was an appeal in proceedings for the revocation of European Patent (UK) No. 1,173,181 (“the Patent”) which concerned a drug called tadalafil, which was sold under the brand name CIALIS for the treatment of erectile disfunction (“ED”) and benign prostatic hyperplasia, and under the brand name ADCIRCA for the treatment of pulmonary arterial hypertension. The revocation proceedings were brought against the proprietor of the Patent, ICOS Corporation, and its exclusive licensee, Eli Lilly & Co (collectively referred to in the decision reported here as “Lilly”). Revocation was sought on grounds including lack of novelty over three publications (referred to as Anderson, Stoner and Oren) and obviousness in the light of a fourth, Daugan. The applicants for revocation also advanced arguments based on entitlement to the claimed priority date of 30 April 2009, added matter and insufficiency. Lilly defended the claim and counterclaimed for threatened infringement. At first instance, Birss J. had held that claims 2 and 12 of the Patent were not entitled to the claimed priority date of 30 April 1999 and that, as such, they lacked novelty and were accordingly invalid. However he held that the remaining claims were entitled to the claimed priority date, were valid and that the claimants would infringe the Patent if they were to launch the products complained of. The claimants appealed, arguing that the judge had failed properly to construe the claims of the Patent (particularly the independently valid claims 1, 7 and 10). They also argued that the judge ought to have held that none of the claims of the Patent was entitled to the claimed priority date and that amendments made to the claims meant that their disclosure extended beyond the disclosure of the application as filed. Further, they argued that the judge had erred in failing to find that Stoner deprived the claims of novelty and in his approach to the issue of obviousness. Birss J. ought to have found that there was nothing inventive in any of the claims. Claims 1 to 7 and 10 of the Patent are set out at [43] of the judgment reported here. There was no dispute as to the correct approach to construction, but the parties disagreed 1 Permission to appeal to the Supreme Court was granted by the Supreme Court on 12 March 2018. [2018] R.P.C., Issue 5 ß Crown copyright 2018. This article contains public sector information licensed under the Open Government Licence v3.0 (http://www. nationalarchives.gov.uk/doc/open-government-licence/version/3/) [2017] EWCA Civ 1671; [2018] R.P.C. 7 364 H5 H6 as to the meaning of claims 7 and 10, both of which were dependent upon claim 1. The dispute concerned the role of the words “said unit dosage form suitable for oral administration up to a maximum total dose of 5mg per day”. The judge had held that the words “suitable for” in claim 1 made it clear that the claim was not limited to the use of this dosage form for any particular purpose and that the words “up to a maximum total dose of 5mg per day” had no effect on the scope of this claim. However he had gone on to find that it formed part of the purpose limitations in claims 7 and 10. The claimants argued that in doing so he had erred as those words were no more of a limitation in claims 7 and 10 than they had been in claim 1. They also argued that the judge had been wrong in construing the words “up to a maximum total dose of 5mg per day” as having the effect that the treatment of sexual dysfunction by the administration of higher doses of tadalafil per day fell outside their scope. There was no dispute that the relevant skilled team would have included a clinical pharmacologist with experience in pharmacokinetics and a clinician specialising in urology. Further, the judge had made findings as to common general knowledge, none of which would appear to have been the subject of challenge on appeal. As to priority, the critical question was whether, as a matter of substance, the subject matter of each of claims 7 and 10 was derivable directly and unambiguously, using common general knowledge, from the priority document relied upon. The judge had held that it was. He had gone on to find that the skilled person would have considered the disclosure of the priority document to be plausible. The claimants argued, inter alia, that the invention disclosed in the priority document was a way of identifying a wide class of inhibitors of a particular cyclic nucleotide phosphodiesterase enzyme, PDE5, by their properties rather than their chemical structure and that the document contained no disclosure of any test in relation to tadalafil save one designed to assess patients’ tolerance to a dose of 10mg daily for seven days. More specifically, they argued that the priority document did not disclose (i) a dosing regimen of up to a maximum total dose of 5mg per day for any drug; (ii) that such a regimen using tadalafil was efficacious in the treatment of ED; or (iii) that any dose within such a regimen using tadalafil was efficacious in the treatment of ED. If claims 7 and 10 were entitled to their claimed priority date, then the only potentially relevant prior art for novelty purposes was Stoner. However, this would only taken to be part of the state of the art by the operation of s.2(3) of the Patents Act 1977 if it was itself entitled to its own claimed priority date. Neither side had adduced any evidence on this question save the Stoner publication itself and the US application from which it claimed priority. Birss J. had held that Stoner was entitled to the priority date claimed but that it did not anticipate claims 7 and 10. Even though it contained clear and unmistakeable directions to do what Lilly claimed to have invented, the judge held that the disclosure was not an enabling one because it asserted that various combinations were efficacious but there was nothing that made it credible or plausible that the particular tadalafil combination referred to would actually work. The claimants argued that the judge had erred in his conclusion on enablement. Lilly disputed this and also argued that the legal and evidential burden on entitlement to priority fell on the claimants and that they had failed to satisfy it. They also argued that the judge had also fallen into error in his assessment that the invention the subject of claims 2 and 12 was disclosed in Stoner in any event. On the issue of obvio (...truncated)