Supreme Court Affirms Current Practice on Inventive Step in Actavis v Icos

The Supreme Court issued its judgment in Icos v Actavis yesterday 27 March, considering the issue of inventive step. The case concerned a patent claiming a specific low dose of the drug tadalafil, known for use in treating male erectile dysfunction. The patentee had argued that it would not have been obvious, prior to the relevant Phase II clinical trials, that the low dose specified in the claims would be safe and effective, given the high dosages which were mentioned in the most relevant prior art. The first instance judge had upheld key claims in the patent on the basis that (a) the results of the clinical studies were not predictable in advance and (b) the expert evidence indicated that although it was "very likely" that the specified dose would have been tested in routine and non-inventive dosing studies, it was not inevitable that such studies would have included the relevant dose.

The Supreme Court, upholding the decision of the Court of Appeal, held that all claims lacked inventive step. In coming to this finding, the Court specifically rejected the submission by Actavis that "the skilled person's repertoire" should embrace all obvious modifications or additions to the state of the art, and that all such subject matter should therefore lack inventive step. It noted that such an approach might preclude any protection for so-called selection patents or improvement patents. The Court also emphasised that it was not establishing any general proposition that the product of well-established or routine enquiries cannot be inventive. However, on the facts of this case, a skilled team seeking to implement the teaching of the prior art would have been "very likely" to test tadalafil at the claimed low dose. At that point, the team would have noted that the drug was safe and effective at that dose and would have arrived at the claimed invention. The claimed invention was therefore obvious. Under these circumstances, any unexpected advantage associated with the new dose (e.g. reduced side effects) simply constitutes a bonus, which does not suffice to establish an inventive step.

The Supreme Court decision appears to be fully consistent with well-established principles for assessing inventive step, and is consistent with the jurisprudence of the European Patent Office on bonus effects (see for example T393/01).