The Obviousness of Preamble Limitations Can Be a Real Headache for Patent Challengers

| Spencer R. CarterHans L. Mayer


Before Lourie, Bryson and O’Malley. Appeal from the Patent Trial and Appeal Board.

Summary: In claims for methods of using apparatuses or compositions, statements of intended purpose in a preamble tend to be limiting.

Lilly filed petitions for IPR against three Teva patents directed to methods for alleviating migraines. The Board concluded that Lilly had failed to show that the challenged claims would have been obvious over the asserted references. While the Board found that Lilly had shown that the prior art disclosed every element of the challenged claims, and a motivation to combine the prior art, Lilly had not shown that a skilled artisan would have had a reasonable expectation of success in combining the references. Lilly appealed.

On appeal, Lilly argued that the Board incorrectly found that Teva’s preambles were limiting because a preamble that contains only a statement of purpose cannot as a matter of law be a claim limitation. The Federal Circuit disagreed, and explained that unlike apparatus and composition claims, claims to methods of using apparatuses or compositions are not directed to what the method “is,” but typically rely entirely on what the method “does.” And what a method does is usually recited in its preamble. Thus, statements of intended purpose in methods of using apparatuses or compositions tends to result in a conclusion that such preamble language is limiting.

Lilly also argued that the Board had imposed a heightened standard – one that required efficacy data - in its analysis of whether the prior art references would have given a skilled artisan a reasonable expectation of success. The Federal Circuit disagreed that the Board imposed such a standard. The Federal Circuit also made clear that a showing of a reasonable expectation of success need not rely on clinical data, nor must it include a demonstration of certainty that the treatment would be successful in every instance.

Editor: Paul Stewart