"Optional" disclosure in prior art reference overcomes negative claim limitation.

Upsher-Smith Labs. v. Pamlab (Fed. Cir. 2005).

Upsher-Smith asserted to patents against Pamlab.  The patents cover a vitamin supplement consisting of vitamin B12 and other active components.  The claims also provide a negative limitation that the supplement is “essentially free of antioxidants.”

The district court dismissed the suit — finding the patents anticipated and obvious based on prior art that disclosed the identical compounds but that “optionally includes” antioxidants.

On appeal, the CAFC affirmed — finding that the optional inclusion of the antioxidants teach “vitamin supplements that both do and do not contain antioxidants. . . . Consequently, Pamlab presented a prima facie case of anticipation.”