In a much awaited decision, the Federal Court of Australia has invalidated the key claim of Pfizer’s patent to the use of a group of compounds, including VIAGRA®, for the treatment of erectile dysfunction, allowing Eli Lilly to keep its highly successful erectile dysfunction (ED) drug Cialis® on the market in Australia.
Eli Lilly is an Indianapolis-based multinational pharmaceutical company, perhaps best known for its revolutionary anti-depressive medication PROZAC®. Global sales of Pfizer’s erectile dysfunction medication VIAGRA® amount to approximately A$2 billion annually.
In 2002, Eli Lilly & Company brought patent proceedings against Pfizer to revoke a claim in Pfizer’s Australian Patent 676571, which provides Pfizer with a monopoly on the use of Viagra® and more generally phosphodiesterase V (PDEv) inhibitors, for treating ED. Shortly after filing these proceedings, Eli Lilly launched Cialis® on the Australian market. Like VIAGRA®, the active ingredient in Cialis®, tadalafil, is a PDEv inhibitor but bears no chemical relationship to the active ingredient in VIAGRA®. Pfizer counter claimed that Eli Lilly’s sales of CIALIS® constituted an infringement of its patent.
In a complex case, Justice Peter Heerey held that Pfizer’s claim to the use of all PDEv inhibitors for the treatment of ED (rather than a specific chemical compound or group of compounds) was not inventive. This conclusion was based, at least in part, on Justice Heerey’s finding that, before Pfizer filed its patent application, Jacob Rajfer and his colleagues at the University of California, Los Angeles had published an article in the prestigious international journal The New England Journal of Medicine which pointed to the utility of phosphodiesterase inhibition in treatment of erection.
Moreover, Justice Heerey rejected Pfizer’s suggestion that VIAGRA® was developed ‘serendipitously’ from research Pfizer were conducting in the angina field. In this respect, Justice Heerey J clearly found that the change in direction of Pfizer’s angina research to erectile dysfunction was linked directly to the impact of the research published in the New England Journal of Medicine.
Justice Heerey also held that the broad claim to the use of any PDEv inhibitor for the treatment of ED was not fairly based on the description in Pfizer’s patent.
Pfizer have appealed against Justice Heerey’s decision. We advise that Gary Cox and Todd Shand from Wray & Associates will be acting for Eli Lilly in these proceedings.
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