Page:Amgen Inc. v. Sanofi.pdf/10

6 the claims to determine whether any block PCSK9 from binding to LDL receptors. See id., at 13–14. The second method is what Amgen calls “conservative substitution.” Id., at 14, 17. This technique requires scientists to: (1) start with an antibody known to perform the described functions; (2) replace select amino acids in the antibody with other amino acids known to have similar properties; and (3) test the resulting antibody to see if it also performs the described functions. See id., at 14–15.

Soon after receiving the ’165 and ’741 patents, Amgen sued Sanofi for infringing them. Sanofi replied that it was not liable to Amgen because the relevant claims were invalid as a matter of law. Invalid, Sanofi said, because Amgen had not enabled a person skilled in the art to make and use all of the antibodies that perform the two functions Amgen described in its claims. See 987 F. 3d, at 1083–1085. While Amgen had identified the amino acid sequences of 26 antibodies that bind to PCSK9 and block it from binding to LDL receptors, Sanofi observed that Amgen’s claims cover potentially millions more undisclosed antibodies that perform these same functions. And, Sanofi argued, neither of the two methods Amgen had outlined for generating additional antibodies with the same functions enable a person skilled in the art to do so reliably. Instead, Sanofi submitted, those methods require scientists to engage in little more than a trial-and-error process of discovery. See id., at 1085.

After lengthy proceedings, the district court granted Sanofi judgment as a matter of law, concluding that the claims at issue “are not enabled.” 2019 WL 4058927, *13 (Del., Aug. 28, 2019). The Federal Circuit affirmed. 987 F. 3d, at 1088. It determined that “no reasonable factfinder could conclude” that Amgen had provided “adequate guidance” to make and use the claimed antibodies “beyond the narrow scope of the [26] working examples” it had identified