Opinion ID: 211469
Heading Depth: 2
Heading Rank: 2

Heading: Identification of Interfering Subject Matter

Text: 38 Having affirmed the district court's determination that an interference-in-fact exists, and that it properly includes those claims directed to specific titanium ratios, this court turns to address Rolabo's procedural argument that the district court erred when it failed to comply with the Board's practice of articulating a precise count of the interference prior to making priority determinations. 39 This court has not yet addressed whether district courts handling interfering patent suits under § 291 must define this interfering subject matter in a way similar to a count. Slip Track Sys., Inc. v. Metal-Lite, Inc., 304 F.3d 1256, 1264 (Fed.Cir.2002). Nevertheless, we have made clear that at least a single description of the interfering subject matter is necessary for a determination of priority. Id. 40 That said, Slip Track does not require a court to refer explicitly to the interfering subject matter as a count, and we believe that in this case the district court was clear about the identity of the interfering subject matter, stating in its opinion all the various claims of the '827 patent are essentially identical to one another and substantially the same as claim 2 of Medichem's patent. Medichem III, 2004 WL 2674632 at . Moreover, to the extent that the district court may not have been clear about whether the tertiary amine limitation was part of the interfering subject matter, we can resolve this issue on appeal. See Slip Track, 304 F.3d at 1264-65 (holding that where the parties . . . dispute only whether one limitation is part of the interfering subject matter, and determination of this issue is dependent upon issues of law alone, we will resolve this issue on appeal.) Accordingly, we hold that the interfering subject matter in this case does not include the limitation of the tertiary amine, and corresponds to claim 17 of Rolabo's '827 patent. See id. 1265 (Since the claims of the '760 patent do not include a wallboard . . . the wallboard cannot be an element of the interfering subject matter in this case, even though it is a limitation in the claims of the '203 patent.). 7