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  • Writer's pictureKirk Hartley

Tobacco Patents on a Method to Reduce Carcinogens in Cigarettes

Amazing what’s out there. This blog post by patent lawyer and molecular biologist Kevin E. Noonan describes litigation over a tobacco company patent aimed at reducing carcinogens in tobacco. After decades of industry denial that cigarettes caused cancer, this seems rather surreal. Here’s a key excerpt:

"The Federal Circuit reaffirmed the primacy of the factual disclosures used to establish obviousness, and how deficiencies thereof can defeat an obviousness claim, in reversing an invalidity determination in Star Scientific, Inc. v. R.J. Reynolds Tobacco Co. It also showed how persistently defendants pursue the tarnish of inequitable conduct even under circumstances where the Federal Circuit has held that no inequitable conduct occurred.

The patents-in-suit, U.S. Patent Nos. 6,202,649 and 6,425,401 (filed as a continuation of the ‘649 patent), were directed to methods for curing tobacco in a way that reduced the amount of a carcinogen, tobacco-specific nitrosamines (TSNAs), in the cured product used in cigarettes and other tobacco-containing products. The patents were specifically directed to "indirect" flue curing with gas or propane heaters. Former methods used "direct" flue curing that mixed the exhaust gasses with the tobacco, but this resulted in an oxygen-free environment that fostered the growth of bacteria on the leaves, leading to production by the bacteria of the carcinogenic TSNAs. The patented methods can be used with either direct or indirect curing methods by using "controlled conditions" involving humidity, temperature, rate of temperature exchange, carbon monoxide levels, carbon dioxide levels, oxygen levels, and how the tobacco plants are arranged in the curing shed. The claims specify "controlling conditions" by "determining and selecting" the "appropriate" values for these variables that results in the reduction of TSNA production "at least one"). However, the patents admit that the choice of these conditions are "more art than science," so need to choose the appropriate combination of these variables; however, the important consideration is maintaining an aerobic environment that prevents bacterial growth. (emphasis added)

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