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Appropriate Level of Ordinary Skill in the Art Pertaining to a Patent for a Method for Treating Ear Infections Is That of a Person with Experience in Pharmaceutical Formulations, Not Just a Pediatrician or General Practitioner

06-1564
September 12, 2007

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Last Month at the Federal Circuit - October 2007

Judges: Michel, Archer (author), Dyk

[Appealed from: D.N.J., Judge Bassler]

In Daiichi Sankyo Co. v. Apotex, Inc., No. 06-1564 (Fed. Cir. Sept. 12, 2007) (precedential opinion), the Federal Circuit reversed the district court’s judgment that U.S. Patent No. 5,401,741 (“the ’741 patent”) was not obvious, finding that the district court clearly erred in its determination of the level of ordinary skill in the art and that the ’741 patent would have been obvious in view of prior art.

Daiichi Sankyo Co., Ltd. (“Daiichi”) is the owner of the ’741 patent, which is directed 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.” Slip op. at 2 (alteration in original).

Apotex, Inc. and Apotex Corp. (collectively “Apotex”) filed an ANDA seeking approval to manufacture a generic ofloxacin ear drop, including a certification that the ’741 patent was invalid and/or not infringed. Following receipt of the ANDA, Daiichi sued Apotex for infringement. The district court construed the claim term “effective to treat” as “efficacious and safe,” and based on that construction and following a bench trial, it concluded that the ’741 patent was not invalid. The district court also found that Daiichi did not intend to deceive the PTO during prosecution of the ’741 patent and that Apotex infringed the ’741 patent. Apotex appealed.

On appeal, the Federal Circuit noted that obviousness is a question of law based on underlying questions of fact. It noted that 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. The Court then turned to the question of the level of ordinary skill in the prior art.

The Court noted that the district court had concluded that the ordinary person skilled in the art pertaining to the ’741 patent “would have a medical degree, experience treating patients with ear infections, and knowledge of the pharmacology and use of antibiotics. This person would be . . . a pediatrician or general practitioner—those doctors who are often the ‘first line of defense’ in treating ear infections and who, by virtue of their medical training, possess basic pharmacological knowledge.” Id. at 3. Apotex argued that the district court clearly erred in its determination of the level of ordinary skill in the art and urged that a person of ordinary skill in the art was instead “a person engaged in developing new pharmaceuticals, formulations and treatment methods, or a specialist in ear treatments such as an otologist, otolaryngologist, or otorhinolaryngologist who also has training in pharmaceutical formulations.” Id. The Federal Circuit agreed and held that the district court clearly erred in finding otherwise.

In so holding, the Federal Circuit explained that factors that may be considered in determining the level of ordinary skill in the art include: (1) the educational level of the inventor; (2) the types 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. It observed that these factors are not exhaustive, but are merely a guide to determining the level of ordinary skill in the art. Applying these factors, the Federal Circuit noted that the inventors of the ’741 patent were specialists in drug and ear treatments, and not general practitioners or pediatricians.

Additionally, noted the Court, others working in the same field as the inventors of the ’741 patent were of the same skill level. Furthermore, in developing the invention, the inventors tested it on guinea pigs, methodology that the Federal Circuit found to be generally outside the realm of a general practitioner or pediatrician. The Court further noted that 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 method without the sort of specialty training that the ’741 patent inventors possessed. Accordingly, the Federal Circuit concluded that the level of ordinary skill in the art applicable to 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.” Id. at 5.

The Court next turned to the question of whether the invention of the ’741 patent would have been obvious to one of ordinary skill in the art at the time of the invention. It noted that the district court’s error in determining the level of ordinary skill in the art of the ’741 patent “tainted its obviousness analysis.” Id. at 6. In view of the correct level of skill in the art and the evidence of record, it concluded that, as a matter of law, the ’741 patent was invalid as obvious. The Court explained that it need not decide whether the claim term “effective to treat” should include not only efficacy but safety because the evidence demonstrated that in view of the correct level of skill in the art, using a topical formulation of ofloxacin to treat ear infections was not only obvious but safe.

Specifically, the Court found the ’741 patent obvious in view of an article published in 1986 by Horst Ganz (“the Ganz reference”). The Court noted that the Ganz reference taught the successful use of ear drops containing ciprofloxacin to treat middle ear infections. It noted that Apotex’s expert testified that ofloxacin was in the same family of antibiotics as ciprofloxacin, and that someone of ordinary skill in the art, e.g., an otologist, would believe it to be highly likely that ofloxacin could also be used safely to treat middle ear infections. It observed that Daiichi failed to dispute Apotex’s expert testimony, relying instead on its own expert, who stated that the Ganz reference would not convey the same teaching to someone of lower skill in the art, such as a general practitioner or pediatrician. It noted that Daiichi’s evidence was, however, based on an incorrect determination of the level of ordinary skill in the art. In view of this evidence, the Federal Circuit held that the invention of the ’741 patent would have been obvious to one having ordinary skill at the time of the invention and reversed the district court’s judgment.