We read in the decission (here):
"Because AstraZeneca conceded infringement for the limited purpose of its summary judgment motion, and because Teva maintains the allegation of infringement upon which its suit is based, it is undisputed for the purpose of this appeal that AstraZeneca's drug is an embodiment within the scope of the asserted claims. See Evans Cooling Sys., Inc. v. Gen. Motors Corp., 125 F.3d 1448, 1451 (Fed. Cir. 1997) ("Although [defendant] bore the burden of proving that the [asserted prior art/accused product] embodied the patented invention or rendered it obvious for purposes of the summary judgment motion, this burden is met by [plaintiff's] allegation, forming the sole basis for the complaint, that the [asserted prior art/accused product] infringes."). It is undisputed that AstraZeneca conceived and reduced its drug to practice before Teva's first conception of the claimed subject matter."
Teva based the appeal in the fact that AstraZeneca “did not understand that crospovidone acted as a stabilizer in its drug prior to Teva's conception, if at all”. The Court of Appeal states that defendant didn’t have to understand it, arguing that:
"Conception occurs "when the inventor has a specific, settled idea, a particular solution to the problem at hand ...." Creative Compounds, LLC v. Starmark Labs., No. 2010-1445, Slip Op. 13 (Fed. Cir. Jun. 24, 2011) quoting Burroughs Wellcome Co. v. Barr Labs., Inc., 40 F.3d 1223, 1228 (Fed. Cir. 1994). But "[a]n inventor need not understand precisely why his invention works in order to achieve an actual reduction to practice." Parker v. Frilette, 462 F.2d 544, 547 (CCPA 1972). In order to establish reduction to practice, the prior inventor must have (1) constructed an embodiment or performed a process that met all the claim limitations and (2) determined that the invention would work for its intended purpose. Mycogen Plant Sci., 243 F.3d at 1332."