Biofer S.p.A. v. Vifor (International) AG

Biofer S.p.A. v. Vifor (International) AG The Federal Circuit affirmed the construction requiring the pH to be maintained between 7.0 and 9.0 throughout the oxidation step, and therefore affirmed non-infringement based on Biofer’s concession under that construction. The court declined to review a separate claim-construction issue not implicated by the stipulated judgment. The decision underscores that repeated specification and prosecution-history statements about maintaining a claimed process condition can turn a numerical range into a throughout-the-step requirement, especially where the stipulated judgment preserves only that issue for appeal. Affirmed. Costs awarded to Vifor. The asserted process claim recited reacting a sugar with bromine “in a solution at a pH between 7.0 and 9.0”; the dispute was whether the pH had to remain in that range throughout the oxidation step. The court held that the claim language, read with the specification’s repeated references to controlling and maintaining pH during activation/oxidation, supported the district court’s construction. The prosecution history reinforced the construction because Biofer relied on inventor testing comparing reactions while “maintaining” pH inside and outside the claimed range to show criticality. Biofer’s appellate “brief excursions” theory was forfeited because it was not presented below, where Biofer had argued that momentary presence in the range could suffice. Because Biofer stipulated it could not prove infringement if the pH had to be maintained throughout the process, the Federal Circuit affirmed non-infringement and declined to reach another claim term not implicated by the judgment. claim construction infringement waiver / forfeiture non-precedential claim construction infringement waiver / forfeiture non-precedential claim construction infringement