Obviousness is a question of law based on underlying questions of fact. Winner Int’l Royalty Corp. v. Wang, 202 F.3d 1340, 1348 (Fed. Cir. 2000). Thus, we review the ultimate determination of obviousness by a district court de novo and the underlying factual inquiries for clear error. Id.

The underlying factual inquiries in an obviousness analysis include: “(1) the scope and content of the prior art; (2) the level of ordinary skill in the prior art; (3) the differences between the claimed invention and the prior art; and (4) objective evidence of nonobviousness.” In re Dembiczak, 175 F.3d 994, 998 (Fed. Cir. 1999). In this case, we begin our analysis with the question of the level of ordinary skill in the prior art.

“Factors that may be considered in determining level of ordinary skill in the art include: (1) the educational level of the inventor; (2) type of problems encountered in the art; (3) prior art solutions to those problems; (4) rapidity with which innovations are made; (5) sophistication of the technology; and (6) educational level of active workers in the field.” Envtl. Designs, Ltd. v. Union Oil Co., 713 F.2d 693, 696 (Fed. Cir. 1983) (citing Orthopedic Equip. Co., Inc. v. All Orthopedic Appliances, Inc., 707 F.3d 1376, 1381-82 (Fed. Cir. 1983)). These factors are not exhaustive but are merely a guide to determining the level of ordinary skill in the art.

The district court aimed low, considering "ordinary skill in the art" to be a someone with a medical degree and knowledge of pharmacology, familiar with the compounds in the claimed invention. The CAFC raised the bar to ear-level.

[T]he 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. [T]he district court clearly erred in finding otherwise.

A prior art reference by Ganz "taught the successful use of ear drops containing ciprofloxacin to treat middle ear infections" without side effects.

The district court dismissed this finding of no side effects, and thus no ototoxicity, because the article reported that use of gyrase inhibitors “should be used only in difficult cases and exclusively by the otologist.” Because an otologist was outside the level of ordinary skill in the art as determined by the district court, the district court found that the reference did not support Apotex’s argument that ofloxacin, a gyrase inhibitor like ciprofloxacin, was effective and safe to treat bacterial ear infections topically. As explained above, the district court’s determination of the level of ordinary skill in the art was incorrect; thus, so, too, was its dismissal of the teaching of the Ganz reference.

Accordingly, the evidence demonstrates that a reasonable jury would have no other choice than to conclude that, in view of the Ganz reference, it would have been obvious to a person engaged in developing pharmaceutical formulations and treatment methods for the ear or to a specialist in ear treatments who also has training in pharmaceutical formulations to use ofloxacin in ear drops to topically treat ear infections.

District court ruling reversed; '741 now a dead issue.