Daiichi Sankyo Co. v. Apotex, Inc. (Fed. Cir. 2007) (reissued as precedential)

    By Robert Dailey —

Much of patent law depends on the attributes of the hypothetical "person having ordinary skill in the art" (PHOSITA).  Particularly, claim construction and obviousness determinations depend on how the court defines PHOSITA for the patent-in-suit.

Nevertheless, Federal Circuit case law provides little guidance.  The 1983 Orthopedic Equipment case articulates six non-exclusive factors that courts may use in determining the characteristics of PHOSITA: (1) education level of the inventor; (2) problems encountered in the art; (3) prior art solutions to the problem; (4) rapidity with which innovations are made; (5) sophistication of the technology; and (6) education level of active workers in the field.  But subsequent case law has added little nuance to this assessment rubric.

An earlier posting on Patent Docs summarizes the holding of the original non-precedential Daiichi Sanko case, issued this July.  Now that the CAFC has reissued the identical opinion as precedential, it’s probably worth considering what the implications might be.

The case involved ofloxacin (at left), a topical antibiotic used for treating ear infections.  Although many antibiotics can cause damage to the ear when applied topically, specialists in the field knew that ciprofloxacin (below) showed no such damage.  Since ofloxacin and ciprofloxacin are antibiotics having similar molecular structures, those aware of ciprofloxacin’s success would have possessed the requisite motivation to use ofloxacin in similar ways.

But the District Court had included pediatricians and general practice physicians within the class of those having ordinary skill in the art.  Since these non-specialist medical practitioners rarely, if ever, use ciprofloxacin to treat ear infections, the court ruled that ofloxacin’s success would not be obvious to PHOSITA.  The Federal Circuit reversed, holding that the District Court should have limited PHOSITA to otologists and persons who develop pharmaceutical formulations.  Since this narrower class of experts would have been aware of ciprofloxacin’s success, the use of ofloxacin to treat the same ailment is obvious.

In this instance, the CAFC probably reached the best result.  After all, PHOSITA’s art field is determined by the nature of the invention.  Non-specialist physicians are not generally in the business of developing and testing new pharmaceutical products.  If we include them within the class of skilled artisans, then almost no pharmaceutical invention would be obvious.  Thus, this case illustrates the dangers of setting the level of ordinary skill too low.

On the other hand, the law bids us look to the person of ordinary skill in the art.  By focusing too much on the skill set of the inventor, we run the risk of defining PHOSITA as a kind of super-skilled artisan.  In fact, PHOSITA is even less bright than the average artisan; otherwise, half of the practitioners in the art field would fall below the standard.  In other words, he’s like the B- student who barely met the minimum qualifications for graduation.

As the CAFC points out, persons included as PHOSITA should at least be capable of carrying out the experiments necessary to create and test the invention.  But if we adorn PHOSITA with too many attributes (i.e., give him the same skills as the inventor), then we create someone for whom everything is obvious.