Opinion ID: 625949
Heading Depth: 4
Heading Rank: 1

Heading: The Isolated DNA Enhancer

Text: On appeal, Sanofi argues that the district court erred by defining “isolated DNA enhancer” to require the enhancer to be “separated . . . from the promoter DNA in its original source.” Claim Construction Order, 2010 WL 2525118, at . Sanofi argues that the claimed “isolated DNA enhancer” can include the native HCMV promoter but concedes that it need not, pointing out that the ’522 patent’s specification teaches that the HCMV enhancer can be used with or without the HCMV IE promoter. See ’522 patent col.2 ll.6–10, 43–56. Appellees respond that Sanofi disclaimed enhancer fragments that include the HCMV IE promoter during prosecution and that the 7 SANOFI-AVENTIS v. GENENTECH disclosure excludes the promoter from its discussion of enhancer-active elements. We agree with the district court that the intrinsic evidence does not support Sanofi’s construction. We have held that an otherwise broadly defined term can be narrowed during prosecution through arguments made to distinguish prior art. Phillips v. AWH Corp., 415 F.3d 1303, 1317 (Fed. Cir. 2005) (en banc). In this case, the applicants made such a disclaimer during prosecution of U.S. Patent Application No. 07/170,140—an ancestor of the application that eventually issued as the ’522 patent—to overcome obviousness rejections against thenpending claims that recited an “isolated enhancer.” Specifically, the examiner had cited two references (Thomsen and Jahn) that disclose HCMV-derived DNA sequences encompassing the HCMV IE enhancer and promoter regions. In a response dated March 14, 1988, the applicants distinguished the cited art, as follows: [N]either of these primary references teaches the preparation of an isolated enhancer region as de- fined by the pending claims. . . . Thomsen et al. expressly discusses promoter sequences . . . . [Jahn] isolates and characterizes a variety of clones and illustrates several maps. The refer- ence does not appear to isolate an enhancer se- quence . . . . J.A. 806–07 (emphasis in original). Thus, the applicants distinguished their isolated enhancer from the cited references, and such statements amount to “a clear and unmistakable disavowal of scope during prosecution” of the ’522 patent. Purdue Pharma L.P. v. Endo Pharms. Inc., 438 F.3d 1123, 1136 (Fed. Cir. SANOFI-AVENTIS v. GENENTECH 8 2006); see also Atofina v. Great Lakes Chem. Corp., 441 F.3d 991, 997–98 (Fed. Cir. 2006). Because Thomsen and Jahn disclose the entire HCMV IE regulatory region, including the claimed enhancer sequences, the applicants cast those references as general disclosures that failed to describe or isolate the HCMV enhancer from its native context within the surrounding viral sequences. Moreover, the applicants underscored the presence of HCMV IE promoter sequences in Thomsen to distinguish that reference from the “isolated enhancer” recited in the pending claims. Hence, their claims must be interpreted to refer to the enhancer separated from the promoter, and we agree with the district court that the term “isolated DNA enhancer” requires an enhancer separated from the promoter DNA in its original source.