Experiments Stern conducted in Bito’s laboratory showed that topical application of a single dose of prostaglandin reduced eye pressure in rhesus monkeys and cats. The experiments did not prove whether continued usage of prostaglandin would result in reduced effectiveness (tachyphylaxis). As repeated doses of prostaglandin would be necessary to treat glaucoma (intraocular pressure (IOP)) successfully, knowing whether tachyphylaxis occurred was essential.

After Stern's semester with Bito ended, Bito furthered his research, which led him to apply for and get 4,599,353.

When Stern found out about the patent, he sued to be added as a co-inventor. Stern also asserted fraudulent concealment, breach of fiduciary duty, and unjust enrichment.

Stern lost in district court on summary judgment, and so appealed to the CAFC (05-1291).

Because “[c]onception is the touchstone of inventorship,” each joint inventor must generally contribute to the conception of the invention. Burroughs Wellcome Co. v. Barr Labs., Inc., 40 F.3d 1223, 1227-28 (Fed. Cir. 1994). Additionally, courts require corroborating evidence of conception. Id. at 1228. However, contribution to one claim is sufficient to be a co-inventor. Ethicon, Inc. v. U.S. Surgical Corp., 135 F.3d 1456, 1460 (Fed. Cir. 1998). Conception is defined as “the ‘formation in the mind of the inventor, of a definite and permanent idea of the complete and operative invention, as it is hereafter to be applied in practice.’” Hybritech Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1376 (Fed. Cir. 1986) (citation omitted). Conception is complete when “the idea is so clearly defined in the inventor’s mind that only ordinary skill would be necessary to reduce the invention to practice, without extensive research or experimentation.” Burroughs Wellcome, 40 F.3d at 1228.

Stern did not have an understanding of the claimed invention, did not discover that prostaglandins have an effect on IOP, did not discover that repetitive application of prostaglandins to the eyes of primates can maintain reduced IOP, and did not conceive of the idea of the use of prostaglandins to reduce IOP in primates. Furthermore, there was no collaboration between Stern and Bito in developing a glaucoma treatment. Stern simply carried out an experiment previously done by Bito on different animals—animals that Bito had already determined would be good models for prostaglandins research. Stern’s contribution is insufficient to support a claim of co-inventorship.

Stern also squealed about his lab notebooks, which Bito had long ago thrown out.

However, regardless of the contents of the notebooks, unwitnessed laboratory notebooks on their own are insufficient to support his claim of co-inventorship. See Hybritech, 802 F.3d at 1378. Thus, the evidence Stern presented was insufficient to corroborate his claim of co-inventorship.