The decision rested on two doctrinal pillars. First, the court invoked the disclosure-dedication rule, holding that subject matter disclosed in the patent specification but not claimed was dedicated to the public domain. Second, the court found prosecution history estoppel barred Actelion's attempt to reclaim ground it had surrendered. The panel's reasoning turned on the prosecution record and patent disclosures showing that pH 13 functioned as the threshold for unexpected-results support.
For pharmaceutical patent counsel, this decision reinforces the high cost of claim narrowing during prosecution. Patentees who narrow claims to overcome rejections face significant barriers to recapturing that surrendered scope through equivalents doctrine later. The ruling also clarifies that disclosed-but-unclaimed subject matter cannot serve as a backdoor to broader protection. In Hatch-Waxman litigation, where generic manufacturers routinely challenge patent scope, this decision signals that careful claim drafting and prosecution strategy are essential—and that narrowing moves made years earlier can determine whether a generic launch proceeds unimpeded.