Otsuka Pharmaceutical Co., Lt v. Thomas Price

SRINIVASAN, Circuit Judge:

The Food, Drug, and Cosmetic Act affords periods of “marketing exclusivity” to pioneering drug products. When a drug earns a period of exclusivity, the Food and Drug Administration must withhold approval of certain competing drugs if various conditions are satisfied. But how does the FDA determine if a new drug bears a sufficiently close relationship to a pioneering drug to fall within the latter’s zone of exclusivity? This case concerns the FDA’s test for making that determination.

The two drugs at issue in this case are antipsychotics primarily used to treat…