Cipla Ltd. & Ors v Glaxo Group Ltd.

Obviousness is assessed objectively by reference to the skilled person, the common general knowledge and each individual item of prior art. Separate documents or uses cannot generally be mosaiced, although the skilled person may consult other information where the prior art naturally directs that course. A technical prejudice may support inventive step only if it is sufficiently general to be attributed to the skilled person. An obvious-to-try route does not invariably require a reasonable expectation of success. No formula may replace the statutory question whether the invention was obvious. An unexpected synergistic effect cannot generally save an obvious combination unless it is described in the specification, possessed by everything within the claim and forms the basis of a properly limited selection.

Four generic pharmaceutical manufacturers sought revocation of a patent relating to an inhaler combining salmeterol, a long-acting β2-agonist, with fluticasone propionate, an inhaled corticosteroid. The principal issue was whether the claimed combination was obvious at the priority date.

The defendant relied on alleged prejudice against regular β2-agonist and inhaled combination therapy, together with the commercial success of the resulting product. The claimants relied principally on the prior use of the Ventide combination inhaler, publications concerning salmeterol and asthma therapy, and common general knowledge.

1. Obviousness. Claim 1 was obvious and invalid. The skilled addressee was a pharmaceutical manufacturing team including clinical pharmacologists and formulation specialists, consulting physicians where appropriate. It was not confined to physicians alone.
2. The skilled person is a legal construct, but objectively identifiable preferences and prejudices of the relevant field may be attributed to that person. A technical prejudice must be general and sufficiently widespread. A view held only by some practitioners cannot establish the necessary prejudice.
3. Each item of prior art had to be considered individually, read in the light of the common general knowledge. Mosaicing was impermissible unless the skilled person would naturally consult another source to supplement the first disclosure. The court adopted the conventional four-stage approach in Windsurfing International v Tabur Marine [1985] RPC 59.
4. The statutory question remained whether the invention was obvious. Evidence that the skilled person would try a course because of a reasonable expectation of a useful result was one possible route to obviousness, but no additional expectation-of-success requirement applied in every case. The assessment remained fact-sensitive.
5. Ventide established the obviousness of combining a β2-agonist and an inhaled steroid to assist compliance. Salmeterol was part of the common general knowledge and was an obvious substitution for salbutamol because of its longer duration. Fluticasone propionate was an obvious up-to-date candidate within the relevant steroid class. The alleged professional controversy amounted to doubts capable of resolution by clinical trials, not a general technical prejudice.
6. The Barnes and Ruffin publications independently supported obviousness. The subsequent success of Seretide could not establish inventiveness because salmeterol was patent-protected and subsequent commercial history could not illuminate the skilled person’s view at the priority date.
7. An unexpected synergistic effect could not save the claim. If relied on, it had to be described in the specification and possessed by everything within the claim. The specification disclosed no relevant effect beyond the natural properties of the components.

The claimants succeeded. The patent invention was held obvious.