CASRIP Newsletter - Autumn 2007, Volume 14, Issue 4
The Federal Circuit Finds Daiichi’s Patent Obvious Through Redefining the “Ordinary Skill in the Art” in Daiichi Sankyo Co. v. Apotex Inc.
By Amanda Carmany-Rampey
In what was originally issued as a nonprecedential opinion, but was reissued on September 12, 2007 as precedential, a three-judge panel of the Federal Circuit invalidated Daiichi’s U.S. Patent No. 5,401,741 (“the ‘741 patent”) as obvious in light of the prior art. The ‘741 patent was directed toward a method for treating ear infections through the topical application of the antibiotic, ofloxacin. The advantage of ofloxacin treatment is that unlike other antibiotics, it does not cause hearing loss.
The Federal Circuit determined that the district court had improperly established the skill level of the “person having ordinary skill in the art” and that the district court’s error “tainted its obviousness analysis.” The Federal Circuit held that since the proper level of skill in the art for the `741 patent was a “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 pharmacological formulations,” a prior art reference regarding the topical use of a related antibiotic to treat ear infections rendered the use of ofloxacin, obvious.
II. PROCEDURAL BACKGROUND
Daiichi filed suit for infringement in New Jersey District Court after the generic drug manufacturer, Apotex, filed an Abbreviated New Drug Application (ANDA) with the Food and Drug Administration for an ofloxacin otic solution. Among its defenses, Apotex raised claims of patent invalidity, anticipation, obviousness, and noninfringment. In its Markman opinion, the district court concluded that a person having ordinary skill in the art “would have a medical degree, experience treating patients with ear infections, and knowledge of the pharmacology and use of antibiotics . . . a pediatrician or general practitioner-those doctors who are often the first line of defense in treating ear infections.”
Also, in interpreting the claims of the ‘741 patent, the court construed the term “effective to treat” as “efficacious and safe,” emphasizing the absence of ototoxicity as a key feature of ofloxacin treatment. In a bench trial, the district court examined a number of prior art references to determine anticipation and obviousness. However, the court found Daiichi’s patent valid and enforceable since it would not be obvious to a person of ordinary skill in the art that ofloxacin applied topically in the ear could treat an ear infection “effectively” and “safely.”
A. Defining the Person Having Ordinary Skill in the Art
Defining the person having ordinary skill in the art is a key step when assessing obviousness under 35 U.S.C. §103, enablement under §112, and in determining the scope of the patent claims. The Federal Circuit has developed a non-exclusive list of six factors that should be considered when assessing the person having ordinary skill in the art: “(1) the education 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) education level of workers in the field.” While the education level of the inventor is probative, Federal Circuit precedent clearly indicates that the person of ordinary skill in the art is not the inventor.
In Daiichi, however, the Federal Circuit focused on the skill level of the inventors, who were “specialists in drug and ear treatments” and others working in the same field as the inventors when rejecting the district court’s determination. Based on this, and the nature of the problem the invention was trying to solve, the Federal Circuit determined that the person having ordinary skill in the art would be “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 pharmacological formulations,” not a pediatrician or general practitioner.
B. Determining Obviousness
In light of the increased skill level of the person having ordinary skill in the art, the Federal Circuit examined a prior art reference, the “Ganz” reference, which taught that topical application of ciprofloxacin, a gyrase inhibitor, was effective in treating ear infections and did not cause ototoxicity. The district court had also examined the Ganz reference and concluded that the reference did not support a finding that a person of ordinary skill in the art would conclude that ofloxacin, another gyrase inhibitor, would be safe for use in treating ear infections. In fact, the district court reasoned that by cautioning ciprofloxacin “should be used only in difficult cases and exclusively by an otologist” the Ganz reference taught away from the use of ofloxacin. However, the Federal Circuit reasoned that when viewed by a highly skilled professional, like an otologist or “a person engaged in developing pharmaceutical formulations and treatment methods for the ear,” the Ganz reference would render the use of ofloxacin to topically treat ear infections obvious. Therefore, the Federal Circuit held Daiichi’s ‘741 patent to be invalid.
In Daiichi, the Federal Circuit focused on the “problem the invention of the patent was trying to solve” as relevant to determining the level of skill in the art. The court reasoned that the animal testing detailed in the written description of the `741 patent would be “outside of the realm of a general practitioner or pediatrician” and developing the invention would require the “specialty training possessed . . . by the `741 patent’s inventors.” Daiichi therefore reaffirms that the inquiry into the person having ordinary skill in the art for determining obviousness should center on the level of skill required to make, not use, the invention.
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