Inventive Step - Substantially all products falling within a claim should make a technical contribution to the art (2016-11-22)
The recent decision of the Court of Appeal of England and Wales in Idenix Pharmaceuticals Inc. v Gilead Sciences Inc. (and others),  EWCA Civ 1089, supports the principle set out in previous English and EPO case law that all products falling within a claim must achieve a technical contribution to the art.
Claim 1 of the patent under consideration was directed to a class of chemical compounds defined by a generic chemical formula. It was accepted that the formula covered billions of individual chemical compounds.
The description of the patent stated that: “The invention is in the area of pharmaceutical chemistry, and is in particular, a 2'-branched pyrimidine nucleoside or 2'-branched purine nucleoside as defined in the claims. The invention is also a pharmaceutical composition comprising the nucleoside, and the nucleoside for use in a method for the treatment of a Flaviviridae infection, such as a hepatitis C virus infection.”
Gilead contended that the claims in issue were invalid for obviousness because they made no technical contribution to the art. They alleged that It was simply not plausible that substantially all of the compounds falling within the scope of the claims would be effective against Flaviviridae.
Other than suitability for treating Flaviviridae infection, no other technical effect was put forward for the compounds by the patentee.
The Court of Appeal agreed with Gilead stating that: “the scope of the monopoly claimed must correspond to and be justified by the technical contribution or, put another way, everything falling in the scope of the claim must be inventive. In the case of a claim to a new class of chemical compounds, the selection of those compounds must not be arbitrary but justified by a technical effect which distinguishes the claimed compounds from many other compounds. Moreover, this technical effect must be shared by substantially all of the claimed compounds.”
The Court of Appeal then considered to what extent the technical affect must be established and at what point in time the technical effect must be established. The Court held that a patent does not necessarily need to include experimental evidence demonstrating that a technical effect is shared by all products falling within the claims. It is sufficient if the patent sets out a plausible or reasonably credible case that the products covered by the claim make the technical contribution over the art. This could be by way of a reasoned hypothesis or an educated guess but must be more than mere speculation. With regard to when and how the technical effect must be established, the Court held that the: “claimed technical effect must therefore be plausible in light of the teaching of the specification and the common general knowledge. The claimed technical effect cannot be established solely by post-published evidence.”
In view of these findings the Court went on to find various claims as lacking in inventive step.
Idenix attempted to limit the claims to cover a subset of the chemical compounds which, in their view, could plausibly be expected to be suitable for treating Flaviviridae infection. The limiting amendment was not allowed for two reasons. Firstly, it was held that the amendment would be inadmissible because it added subject matter - namely the identity of the chemical compounds in the subgroup claimed to be effective. Secondly, the Court was not convinced that, even for the compounds of the limited subgroup, the teaching of the patent made it plausible that they would all be suitable for treating Flaviviridae infection.
The patent was revoked for lack of inventive step and on other grounds.