AbbVie's patents claimed a class or genus of fully human IL-12 antibodies that consisted of about 300 members with a range of IL-12-binding affinities; Stelara fell within this genus. Janssen asserted that although the patents tried to claim a large genus of antibodies, the antibodies that were actually described in the patents were limited to a group of closely related, structurally similar antibodies that are all derived from the same lead antibody, and so were not representative of the large genus that was claimed. Because of this asserted discrepancy between what was claimed and what was described in the patents, Janssen said that the patents failed to meet the so-called 'written description' requirement of patent law, which states that a patent must adequately describe the technology that is sought to be patented in order to show that a person really has invented it.
By contrast, AbbVie argued that the described antibodies did reflect the entire genus, largely because these antibodies had a range of binding affinities that matched the range of binding affinities in the entire genus. But the appeals court disagreed, noting that the patents did not give “any example, or even the possibility” of antibodies other than those having VH3-type heavy chains and λ-type light chains, and so were not representative of the claimed genus of antibodies. Moreover, the court noted that Stelara “differs considerably” compared to the antibodies described in the '128 and '485 patents, as Stelara has VH5-type heavy chains and κ-type light chains and only about 50% sequence similarity in the variable regions.
