Opinion ID: 4190033
Heading Depth: 3
Heading Rank: 3

Heading: Yong–Rui Zou et al, “Cre-loxP-mediated Gene

Text: Replacement: A Mouse Strain Producing Hu- manized Antibodies,” 4(12) Current Biology 1099 (1994) (“Zou”). Dr. Rajewsky co-authored both the Taki and Zou referREGENERON PHARMACEUTICALS v. MERUS N.V. 9 ences. Further, Dr. Alt, another inventor, co-invented WIPO Patent Publication No. WO 91/00906 entitled “Chimeric and Transgenic Animals Capable of Producing Human Antibodies,” credited to Clive Wood et al. (“Wood”). Collectively, the Brüggemann, Taki, Zou, and Wood references are the “Withheld References.” 3 Given their prior work, Regeneron recruited Drs. Alt and Rajewsky to its scientific advisory board to work on the claimed mouse before Regeneron filed the ’018 patent. During prosecution, these individuals corresponded with Dr. Murphy, an ’018 patent inventor, expressing concerns about his characterizations of the prior art in related publications. Dr. Smeland knew of the third party submission as well as all four Withheld References during prosecution, yet withheld them from the ’018 patent’s examiner. Although Regeneron did not disclose the Withheld References during prosecution of the ’018 patent, once the ’018 patent had been allowed, Regeneron disclosed the Withheld References to the PTO in every related application having the same specification and similar claims. Merus contends that Regeneron’s failure to disclose the Withheld References constituted inequitable conduct. Regeneron responds that Dr. Smeland was under no obligation to disclose these references because they were not but-for material. 3 The district court also found that certain withheld litigation documents filed in European Opposition proceedings in 2013 were also but-for material. Regeneron argues that legal documents prepared for litigation cannot be but-for material. Appellant’s Br. 48–49. Because we do not rely on these litigation documents for our holding, we need not address this issue. 10 REGENERON PHARMACEUTICALS v. MERUS N.V.