Page:Amgen Inc. v. Sanofi.pdf/6

2 Amgen’s patents failed to meet this standard because they sought to claim for Amgen’s exclusive use potentially millions more antibodies than the company had taught scientists to make. In the end, both the district court and Federal Circuit sided with Sanofi. The question we face is whether to disturb their judgment.

The immune system produces antibodies as a defense to foreign agents called antigens. When a particular antigen—a virus, for example—enters the body, the immune system generates antibodies to attack it. In a successful attack, the antibodies target and bind to the antigen, stopping it from causing harm to the body. See Brief for Sir Gregory Paul Winter et al. as Amici Curiae 8 (Winter Brief); M. Lemley & J. Sherkow, The Antibody Patent Paradox, 132 Yale L. J. 994, 1001–1002 (2023).

Antibodies are incredibly diverse. Some scientists estimate that there may be as many unique antibodies as there are stars in the galaxy. See id., at 1003; see also B. Briney, A. Inderbitzin, C. Joyce, & D. Burton, Commonality Despite Exceptional Diversity in the Baseline Human Antibody Repertoire, 566 Nature 393, 397 (No. 7744, Feb. 2019) (estimating that the immune system could potentially generate up to a quintillion unique antibodies). This diversity shows up in both structure and function.

Start with structure. “When scientists refer to an antibody’s ‘structure,’ ” they may have in mind “several related concepts,” each of which describes “what an antibody is.” Winter Brief 10. Antibodies are made up of amino acids, and scientists commonly identify a particular antibody according to its specific sequence of amino acids—what they call an antibody’s “ ‘primary structure.’ ” Id., at 9–10. But antibodies are not just linear chains of amino acids. As the