Level of Skill in the Art of Treating Ear Infections Includes Persons Developing Pharmaceutical Formulations

In Daiichi Sankyo Co., LTD v. Apotex, Inc., et al. (reissued as a precedential opinion on Septmembr 12, 2006), the Federal Circuit looked to the experience of the inventors to hold that prior art publication directed at "a highly, highly subspecialized physician" was with the level of ordinary skill in the art of treating bacterial ear infections by topically administering the antibiotic ofloxacin into the ear:

The ’741 patent is drawn to a method for treating bacterial ear infections by topically administering the antibiotic ofloxacin into the ear. Claim 1 is representative and states "[a] method for treating otopathy which comprises the topical otic administration of an amount of ofloxacin or a salt thereof effective to treat otopathy in a pharmaceutically acceptable carrier to the area affected with otopathy." ’741 Patent, col.6 ll.36-39.

. . . The art involved in the ’741 patent is the creation of a compound to treat ear infections without damaging a patient's hearing. The inventors of the ’741 patent were specialists in drug and ear treatments—not general practitioners or pediatricians. At the time of the invention, Inventor Sato was a university
professor specializing in otorhinolaryngology; Inventor Handa was a clinical
development department manager at Daiichi, where he was involved with new drug
development and clinical trials; and Inventor Kitahara was a research scientist at Daiichi engaged in the research and development of antibiotics. Additionally, others working in the same field as the inventors of the ’741 patent were of the same skill level. See Daiichi Material for [C]onference on Development, at 1 (Nov. 11, 1987) (stating that "there are many voices among medical persons concerned with otorhinolaryngology for demanding development of an otic solution making use of [ofloxacin]").

Further, the problem the invention of the ’741 patent was trying to solve was to create a topical antibiotic compound to treat ear infections (otopathy) that did not have damage to the ear as a side effect. ’741 Patent, col.1 ll.23-34. Indeed, most of the written description details the inventors’ testing ofloxacin on guinea pigs and their findings that ototoxicity did not result from the use of their compound. Such animal testing is traditionally outside the realm of a general practitioner or pediatrician. Finally, while a general practitioner or pediatrician could (and would) prescribe the invention of the ’741 patent to treat ear infections, he would not have the training or knowledge to develop the claimed compound absent some specialty training such as that possessed by the ’741 patent’s inventors. Accordingly, the level of ordinary skill in the art of the ’741 patent is that of a person engaged in developing pharmaceutical formulations and treatment methods for the ear or a specialist in ear treatments such as an otologist, otolaryngologist, or otorhinolaryngologist who also has training in pharmaceutical formulations. Thus, the district court clearly erred in finding otherwise.

. . . Daiichi’s expert opined that the Ganz reference disclosed "nothing at all" relevant. This opinion was based on the fact that the article was directed at "a highly, highly subspecialized physician . . . which would be the otologist or the ear doctor" not a primary care physician or general practitioner. Trial Tr. Vol. 7, 72-73 Nov. 11, 2005. He further explained that the article did not render the invention of the ’741 patent obvious "most importantly because those of ordinary skill are defined as a population . . . of physicians that are completely different than the audience Dr. Ganz [the author] was writing to." Id. at 73-74. Thus, Daiichi’s evidence as to why this reference did not render the invention of the ’741 patent obvious was based on an improper determination of the level of skill in the art.