On appeal, the Federal Circuit found the '463 patent, which claimed the timolol/ brimonidine combination, invalid as obvious. See Allergan, Inc. v. Sandoz Inc. ("Combigan® I Appeal"), 726 F.3d 1286, 1294 (Fed. Cir. 2013). However, unlike the '463 patent, claim 4 of the '149 patent contained the additional limitation that the "daily number of doses of brimonidine be reduced from 3 to 2 times a day without loss of efficacy."

Obviousness "is a legal conclusion based on underlying facts," including "the scope and content of the prior art, the differences between the prior art and the claimed invention, the level of ordinary skill in the art, and any relevant secondary considerations." Allergan, Inc. v. Sandoz Inc., 726 F.3d 1286, 1290-91 (Fed. Cir. 2013). In response to Oxbo's motion, H&S points to several different prior art combinations.

"The determination of obviousness under 35 U.S.C. § 103 is a legal conclusion based on underlying facts." Allergan, Inc. v. Sandoz Inc., 726 F.3d 1286, 1290 (Fed. Cir. 2013) cert. denied, 134 S. Ct. 1764. These factual underpinnings include: (1) the scope of content of the prior art; (2) the difference between the prior art and asserted claims; (3) the level of ordinary skill in the relevant art; and (4) the objective evidence of non- obviousness. See Graham v. John Deere Co. of Kan. City, 383 U.S. 1, 17-18 (1966).