Pfizer Overseas Pharmaceuticals & Ors v Eli Lilly & Co & Ors

In the High Court of Australia, Pfizer Overseas Pharmaceuticals and others (the appellants) appealed against a decision of the Full Federal Court concerning the validity of certain patent claims held by Eli Lilly and Company and others (the respondents). The dispute centred on the respondents' patent for a pharmaceutical compound known as duloxetine, which is the active ingredient in the antidepressant medication Cymbalta. The appellants sought to market generic versions of duloxetine, alleging that the respondents' patent was invalid.

The primary legal issue before the High Court was whether the respondents' patent claims, specifically claims 1 and 2, were valid and infringed by the appellants. This involved a determination of whether the patent sufficiently disclosed the invention, particularly in relation to the compound's therapeutic use, and whether the claims were novel and involved an inventive step. The appellants contended that the patent lacked sufficient disclosure and that the claimed invention was obvious in light of prior art.

The High Court, in a joint judgment delivered by Gleeson CJ and Hayne J, found that the patent claims were valid. Their Honours reasoned that the patent specification adequately disclosed the invention, including the therapeutic use of duloxetine, by providing sufficient information to enable a skilled person to identify and use the compound for its intended purpose. The Court applied the principles of patent law concerning sufficiency of disclosure, novelty, and inventive step, finding that the respondents had met the requirements of the Patents Act 1990 (Cth). The appeal was accordingly dismissed.